This section presents the API reference for the SQL Expression Language. For a full introduction to its usage, see SQL Expression Language Tutorial.
The expression package uses functions to construct SQL expressions. The return value of each function is an object instance which is a subclass of ClauseElement.
Return an Alias object.
An Alias represents any FromClause with an alternate name assigned within SQL, typically using the AS clause when generated, e.g. SELECT * FROM table AS aliasname.
Similar functionality is available via the alias() method available on all FromClause subclasses.
When an Alias is created from a Table object, this has the effect of the table being rendered as tablename AS aliasname in a SELECT statement.
For select() objects, the effect is that of creating a named subquery, i.e. (select ...) AS aliasname.
The name parameter is optional, and provides the name to use in the rendered SQL. If blank, an “anonymous” name will be deterministically generated at compile time. Deterministic means the name is guaranteed to be unique against other constructs used in the same statement, and will also be the same name for each successive compilation of the same statement object.
Parameters: |
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Join a list of clauses together using the AND operator.
The & operator is also overloaded on all ColumnElement subclasses to produce the same result.
Return an ascending ORDER BY clause element.
e.g.:
someselect.order_by(asc(table1.mycol))
produces:
ORDER BY mycol ASC
Return a BETWEEN predicate clause.
Equivalent of SQL clausetest BETWEEN clauseleft AND clauseright.
The between() method on all ColumnElement subclasses provides similar functionality.
Create a bind parameter clause with the given key.
Parameters: |
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Produce a CASE statement.
The expressions used for THEN and ELSE, when specified as strings, will be interpreted as bound values. To specify textual SQL expressions for these, use the literal_column() construct.
The expressions used for the WHEN criterion may only be literal strings when “value” is present, i.e. CASE table.somecol WHEN “x” THEN “y”. Otherwise, literal strings are not accepted in this position, and either the text(<string>) or literal(<string>) constructs must be used to interpret raw string values.
Usage examples:
case([(orderline.c.qty > 100, item.c.specialprice),
(orderline.c.qty > 10, item.c.bulkprice)
], else_=item.c.regularprice)
case(value=emp.c.type, whens={
'engineer': emp.c.salary * 1.1,
'manager': emp.c.salary * 3,
})
Using literal_column(), to allow for databases that do not support bind parameters in the then clause. The type can be specified which determines the type of the case() construct overall:
case([(orderline.c.qty > 100,
literal_column("'greaterthan100'", String)),
(orderline.c.qty > 10, literal_column("'greaterthan10'",
String))
], else_=literal_column("'lethan10'", String))
Return a CAST function.
Equivalent of SQL CAST(clause AS totype).
Use with a TypeEngine subclass, i.e:
cast(table.c.unit_price * table.c.qty, Numeric(10,4))
or:
cast(table.c.timestamp, DATE)
Return a textual column clause, as would be in the columns clause of a SELECT statement.
The object returned is an instance of ColumnClause, which represents the “syntactical” portion of the schema-level Column object. It is often used directly within select() constructs or with lightweight table() constructs.
Note that the column() function is not part of the sqlalchemy namespace. It must be imported from the sql package:
from sqlalchemy.sql import table, column
Parameters: |
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See ColumnClause for further examples.
Return the clause expression COLLATE collation.
e.g.:
collate(mycolumn, 'utf8_bin')
produces:
mycolumn COLLATE utf8_bin
Represent a DELETE statement via the Delete SQL construct.
Similar functionality is available via the delete() method on Table.
Parameters: |
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See also:
Deletes - SQL Expression Tutorial
Return a descending ORDER BY clause element.
e.g.:
someselect.order_by(desc(table1.mycol))
produces:
ORDER BY mycol DESC
Return a DISTINCT clause.
e.g.:
distinct(a)
renders:
DISTINCT a
Return an EXCEPT of multiple selectables.
The returned object is an instance of CompoundSelect.
Return an EXCEPT ALL of multiple selectables.
The returned object is an instance of CompoundSelect.
Return an EXISTS clause as applied to a Select object.
Calling styles are of the following forms:
# use on an existing select()
s = select([table.c.col1]).where(table.c.col2==5)
s = exists(s)
# construct a select() at once
exists(['*'], **select_arguments).where(criterion)
# columns argument is optional, generates "EXISTS (SELECT *)"
# by default.
exists().where(table.c.col2==5)
Return the clause extract(field FROM expr).
Return a False_ object, which compiles to false, or the boolean equivalent for the target dialect.
Generate SQL function expressions.
func is a special object instance which generates SQL functions based on name-based attributes, e.g.:
>>> print func.count(1)
count(:param_1)
The element is a column-oriented SQL element like any other, and is used in that way:
>>> print select([func.count(table.c.id)])
SELECT count(sometable.id) FROM sometable
Any name can be given to func. If the function name is unknown to SQLAlchemy, it will be rendered exactly as is. For common SQL functions which SQLAlchemy is aware of, the name may be interpreted as a generic function which will be compiled appropriately to the target database:
>>> print func.current_timestamp()
CURRENT_TIMESTAMP
To call functions which are present in dot-separated packages, specify them in the same manner:
>>> print func.stats.yield_curve(5, 10)
stats.yield_curve(:yield_curve_1, :yield_curve_2)
SQLAlchemy can be made aware of the return type of functions to enable type-specific lexical and result-based behavior. For example, to ensure that a string-based function returns a Unicode value and is similarly treated as a string in expressions, specify Unicode as the type:
>>> print func.my_string(u'hi', type_=Unicode) + ' ' + \
... func.my_string(u'there', type_=Unicode)
my_string(:my_string_1) || :my_string_2 || my_string(:my_string_3)
The object returned by a func call is usually an instance of Function. This object meets the “column” interface, including comparison and labeling functions. The object can also be passed the execute() method of a Connection or Engine, where it will be wrapped inside of a SELECT statement first:
print connection.execute(func.current_timestamp()).scalar()
In a few exception cases, the func accessor will redirect a name to a built-in expression such as cast() or extract(), as these names have well-known meaning but are not exactly the same as “functions” from a SQLAlchemy perspective.
New in version 0.8: func can return non-function expression constructs for common quasi-functional names like cast() and extract().
Functions which are interpreted as “generic” functions know how to calculate their return type automatically. For a listing of known generic functions, see Generic Functions.
Represent an INSERT statement via the Insert SQL construct.
Similar functionality is available via the insert() method on Table.
Parameters: |
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If both values and compile-time bind parameters are present, the compile-time bind parameters override the information specified within values on a per-key basis.
The keys within values can be either Column objects or their string identifiers. Each key may reference one of:
If a SELECT statement is specified which references this INSERT statement’s table, the statement will be correlated against the INSERT statement.
Return an INTERSECT of multiple selectables.
The returned object is an instance of CompoundSelect.
Return an INTERSECT ALL of multiple selectables.
The returned object is an instance of CompoundSelect.
Return a JOIN clause element (regular inner join).
The returned object is an instance of Join.
Similar functionality is also available via the join() method on any FromClause.
Parameters: |
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To chain joins together, use the FromClause.join() or FromClause.outerjoin() methods on the resulting Join object.
Return a Label object for the given ColumnElement.
A label changes the name of an element in the columns clause of a SELECT statement, typically via the AS SQL keyword.
This functionality is more conveniently available via the label() method on ColumnElement.
Return a literal clause, bound to a bind parameter.
Literal clauses are created automatically when non- ClauseElement objects (such as strings, ints, dates, etc.) are used in a comparison operation with a ColumnElement subclass, such as a Column object. Use this function to force the generation of a literal clause, which will be created as a BindParameter with a bound value.
Parameters: |
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Return a textual column expression, as would be in the columns clause of a SELECT statement.
The object returned supports further expressions in the same way as any other column object, including comparison, math and string operations. The type_ parameter is important to determine proper expression behavior (such as, ‘+’ means string concatenation or numerical addition based on the type).
Parameters: |
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Return a negation of the given clause, i.e. NOT(clause).
The ~ operator is also overloaded on all ColumnElement subclasses to produce the same result.
Return a Null object, which compiles to NULL.
Return a NULLS FIRST ORDER BY clause element.
e.g.:
someselect.order_by(desc(table1.mycol).nullsfirst())
produces:
ORDER BY mycol DESC NULLS FIRST
Return a NULLS LAST ORDER BY clause element.
e.g.:
someselect.order_by(desc(table1.mycol).nullslast())
produces:
ORDER BY mycol DESC NULLS LAST
Join a list of clauses together using the OR operator.
The | operator is also overloaded on all ColumnElement subclasses to produce the same result.
Create an ‘OUT’ parameter for usage in functions (stored procedures), for databases which support them.
The outparam can be used like a regular function parameter. The “output” value will be available from the ResultProxy object via its out_parameters attribute, which returns a dictionary containing the values.
Return an OUTER JOIN clause element.
The returned object is an instance of Join.
Similar functionality is also available via the outerjoin() method on any FromClause.
Parameters: |
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To chain joins together, use the FromClause.join() or FromClause.outerjoin() methods on the resulting Join object.
Produce an OVER clause against a function.
Used against aggregate or so-called “window” functions, for database backends that support window functions.
E.g.:
from sqlalchemy import over
over(func.row_number(), order_by='x')
Would produce “ROW_NUMBER() OVER(ORDER BY x)”.
Parameters: |
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This function is also available from the func construct itself via the FunctionElement.over() method.
New in version 0.7.
Returns a SELECT clause element.
Similar functionality is also available via the select() method on any FromClause.
The returned object is an instance of Select.
All arguments which accept ClauseElement arguments also accept string arguments, which will be converted as appropriate into either text() or literal_column() constructs.
See also:
Selecting - Core Tutorial description of select().
Parameters: |
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Return an Alias object derived from a Select.
*args, **kwargs
all other arguments are delivered to the select() function.
Represent a textual table clause.
The object returned is an instance of TableClause, which represents the “syntactical” portion of the schema-level Table object. It may be used to construct lightweight table constructs.
Note that the table() function is not part of the sqlalchemy namespace. It must be imported from the sql package:
from sqlalchemy.sql import table, column
Parameters: |
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See TableClause for further examples.
Create a SQL construct that is represented by a literal string.
E.g.:
t = text("SELECT * FROM users")
result = connection.execute(t)
The advantages text() provides over a plain string are backend-neutral support for bind parameters, per-statement execution options, as well as bind parameter and result-column typing behavior, allowing SQLAlchemy type constructs to play a role when executing a statement that is specified literally.
Bind parameters are specified by name, using the format :name. E.g.:
t = text("SELECT * FROM users WHERE id=:user_id")
result = connection.execute(t, user_id=12)
To invoke SQLAlchemy typing logic for bind parameters, the bindparams list allows specification of bindparam() constructs which specify the type for a given name:
t = text("SELECT id FROM users WHERE updated_at>:updated",
bindparams=[bindparam('updated', DateTime())]
)
Typing during result row processing is also an important concern. Result column types are specified using the typemap dictionary, where the keys match the names of columns. These names are taken from what the DBAPI returns as cursor.description:
t = text("SELECT id, name FROM users",
typemap={
'id':Integer,
'name':Unicode
}
)
The text() construct is used internally for most cases when a literal string is specified for part of a larger query, such as within select(), update(), insert() or delete(). In those cases, the same bind parameter syntax is applied:
s = select([users.c.id, users.c.name]).where("id=:user_id")
result = connection.execute(s, user_id=12)
Using text() explicitly usually implies the construction of a full, standalone statement. As such, SQLAlchemy refers to it as an Executable object, and it supports the Executable.execution_options() method. For example, a text() construct that should be subject to “autocommit” can be set explicitly so using the autocommit option:
t = text("EXEC my_procedural_thing()").\
execution_options(autocommit=True)
Note that SQLAlchemy’s usual “autocommit” behavior applies to text() constructs - that is, statements which begin with a phrase such as INSERT, UPDATE, DELETE, or a variety of other phrases specific to certain backends, will be eligible for autocommit if no transaction is in progress.
Parameters: |
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Return a True_ object, which compiles to true, or the boolean equivalent for the target dialect.
Return a SQL tuple.
Main usage is to produce a composite IN construct:
tuple_(table.c.col1, table.c.col2).in_(
[(1, 2), (5, 12), (10, 19)]
)
Warning
The composite IN construct is not supported by all backends, and is currently known to work on Postgresql and MySQL, but not SQLite. Unsupported backends will raise a subclass of DBAPIError when such an expression is invoked.
Coerce the given expression into the given type, on the Python side only.
type_coerce() is roughly similar to cast(), except no “CAST” expression is rendered - the given type is only applied towards expression typing and against received result values.
e.g.:
from sqlalchemy.types import TypeDecorator
import uuid
class AsGuid(TypeDecorator):
impl = String
def process_bind_param(self, value, dialect):
if value is not None:
return str(value)
else:
return None
def process_result_value(self, value, dialect):
if value is not None:
return uuid.UUID(value)
else:
return None
conn.execute(
select([type_coerce(mytable.c.ident, AsGuid)]).\
where(
type_coerce(mytable.c.ident, AsGuid) ==
uuid.uuid3(uuid.NAMESPACE_URL, 'bar')
)
)
Return a UNION of multiple selectables.
The returned object is an instance of CompoundSelect.
A similar union() method is available on all FromClause subclasses.
Return a UNION ALL of multiple selectables.
The returned object is an instance of CompoundSelect.
A similar union_all() method is available on all FromClause subclasses.
Represent an UPDATE statement via the Update SQL construct.
E.g.:
from sqlalchemy import update
stmt = update(users).where(users.c.id==5).\
values(name='user #5')
Similar functionality is available via the update() method on Table:
stmt = users.update().\
where(users.c.id==5).\
values(name='user #5')
Parameters: |
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If both values and compile-time bind parameters are present, the compile-time bind parameters override the information specified within values on a per-key basis.
The keys within values can be either Column objects or their string identifiers (specifically the “key” of the Column, normally but not necessarily equivalent to its “name”). Normally, the Column objects used here are expected to be part of the target Table that is the table to be updated. However when using MySQL, a multiple-table UPDATE statement can refer to columns from any of the tables referred to in the WHERE clause.
The values referred to in values are typically:
When combining select() constructs within the values clause of an update() construct, the subquery represented by the select() should be correlated to the parent table, that is, providing criterion which links the table inside the subquery to the outer table being updated:
users.update().values(
name=select([addresses.c.email_address]).\
where(addresses.c.user_id==users.c.id).\
as_scalar()
)
See also:
Inserts and Updates - SQL Expression Language Tutorial
Bases: sqlalchemy.sql.expression.FromClause
Represents an table or selectable alias (AS).
Represents an alias, as typically applied to any table or sub-select within a SQL statement using the AS keyword (or without the keyword on certain databases such as Oracle).
This object is constructed from the alias() module level function as well as the FromClause.alias() method available on all FromClause subclasses.
return an alias of this FromClause.
This is shorthand for calling:
from sqlalchemy import alias
a = alias(self, name=name)
See alias() for details.
An alias for the columns attribute.
A named-based collection of ColumnElement objects maintained by this FromClause.
The columns, or c collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:
select([mytable]).where(mytable.c.somecolumn == 5)
Compare this ClauseElement to the given ClauseElement.
Subclasses should override the default behavior, which is a straight identity comparison.
**kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see ColumnElement)
Compile this SQL expression.
The return value is a Compiled object. Calling str() or unicode() on the returned value will yield a string representation of the result. The Compiled object also can return a dictionary of bind parameter names and values using the params accessor.
Parameters: |
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Return corresponding_column for the given column, or if None search for a match in the given dictionary.
Given a ColumnElement, return the exported ColumnElement object from this Selectable which corresponds to that original Column via a common ancestor column.
Parameters: |
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the given ColumnElement, if the given ColumnElement is actually present within a sub-element of this FromClause. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this FromClause.
return a SELECT COUNT generated against this FromClause.
Return the collection of ForeignKey objects which this FromClause references.
return a join of this FromClause against another FromClause.
return an outer join of this FromClause against another FromClause.
Return a copy with bindparam() elements replaced.
Returns a copy of this ClauseElement with bindparam() elements replaced with values taken from the given dictionary:
>>> clause = column('x') + bindparam('foo')
>>> print clause.compile().params
{'foo':None}
>>> print clause.params({'foo':7}).compile().params
{'foo':7}
Return the collection of Column objects which comprise the primary key of this FromClause.
replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this FromClause.
return a SELECT of this FromClause.
Apply a ‘grouping’ to this ClauseElement.
This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by select() constructs when placed into the FROM clause of another select(). (Note that subqueries should be normally created using the Select.alias() method, as many platforms require nested SELECT statements to be named).
As expressions are composed together, the application of self_group() is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like x OR (y AND z) - AND takes precedence over OR.
The base self_group() method of ClauseElement just returns self.
Return a copy with bindparam() elements replaced.
Same functionality as params(), except adds unique=True to affected bind parameters so that multiple statements can be used.
Bases: sqlalchemy.sql.expression.ColumnElement
Represent an expression that is LEFT <operator> RIGHT.
A BinaryExpression is generated automatically whenever two column expressions are used in a Python binary expresion:
>>> from sqlalchemy.sql import column
>>> column('a') + column('b')
<sqlalchemy.sql.expression.BinaryExpression object at 0x101029dd0>
>>> print column('a') + column('b')
a + b
Implement the == operator.
In a column context, produces the clause a = b. If the target is None, produces a IS NULL.
Implement the <= operator.
In a column context, produces the clause a <= b.
Implement the < operator.
In a column context, produces the clause a < b.
Implement the != operator.
In a column context, produces the clause a != b. If the target is None, produces a IS NOT NULL.
provides a constant ‘anonymous label’ for this ColumnElement.
This is a label() expression which will be named at compile time. The same label() is returned each time anon_label is called so that expressions can reference anon_label multiple times, producing the same label name at compile time.
the compiler uses this function automatically at compile time for expressions that are known to be ‘unnamed’ like binary expressions and function calls.
Produce a asc() clause against the parent object.
Produce a between() clause against the parent object, given the lower and upper range.
Produce a collate() clause against the parent object, given the collation string.
Compare this BinaryExpression against the given BinaryExpression.
Compile this SQL expression.
The return value is a Compiled object. Calling str() or unicode() on the returned value will yield a string representation of the result. The Compiled object also can return a dictionary of bind parameter names and values using the params accessor.
Parameters: |
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Implement the ‘concat’ operator.
In a column context, produces the clause a || b, or uses the concat() operator on MySQL.
Implement the ‘contains’ operator.
In a column context, produces the clause LIKE '%<other>%'
Produce a desc() clause against the parent object.
Produce a distinct() clause against the parent object.
Implement the ‘endswith’ operator.
In a column context, produces the clause LIKE '%<other>'
Return a column expression.
Part of the inspection interface; returns self.
Implement the ilike operator.
In a column context, produces the clause a ILIKE other.
Implement the in operator.
In a column context, produces the clause a IN other. “other” may be a tuple/list of column expressions, or a select() construct.
Implement the IS operator.
Normally, IS is generated automatically when comparing to a value of None, which resolves to NULL. However, explicit usage of IS may be desirable if comparing to boolean values on certain platforms.
New in version 0.7.9.
See also
Implement the IS NOT operator.
Normally, IS NOT is generated automatically when comparing to a value of None, which resolves to NULL. However, explicit usage of IS NOT may be desirable if comparing to boolean values on certain platforms.
New in version 0.7.9.
See also
Produce a column label, i.e. <columnname> AS <name>.
This is a shortcut to the label() function.
if ‘name’ is None, an anonymous label name will be generated.
Implement the like operator.
In a column context, produces the clause a LIKE other.
Implements the ‘match’ operator.
In a column context, this produces a MATCH clause, i.e. MATCH '<other>'. The allowed contents of other are database backend specific.
implement the NOT ILIKE operator.
This is equivalent to using negation with ColumnOperators.ilike(), i.e. ~x.ilike(y).
New in version 0.8.
See also
implement the NOT IN operator.
This is equivalent to using negation with ColumnOperators.in_(), i.e. ~x.in_(y).
New in version 0.8.
See also
implement the NOT LIKE operator.
This is equivalent to using negation with ColumnOperators.like(), i.e. ~x.like(y).
New in version 0.8.
See also
Produce a nullsfirst() clause against the parent object.
Produce a nullslast() clause against the parent object.
produce a generic operator function.
e.g.:
somecolumn.op("*")(5)
produces:
somecolumn * 5
This function can also be used to make bitwise operators explicit. For example:
somecolumn.op('&')(0xff)
is a bitwise AND of the value in somecolumn.
Parameters: |
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Return a copy with bindparam() elements replaced.
Returns a copy of this ClauseElement with bindparam() elements replaced with values taken from the given dictionary:
>>> clause = column('x') + bindparam('foo')
>>> print clause.compile().params
{'foo':None}
>>> print clause.params({'foo':7}).compile().params
{'foo':7}
Return True if the given ColumnElement has a common ancestor to this ColumnElement.
Implement the startwith operator.
In a column context, produces the clause LIKE '<other>%'
Return a copy with bindparam() elements replaced.
Same functionality as params(), except adds unique=True to affected bind parameters so that multiple statements can be used.
Bases: sqlalchemy.sql.expression.ColumnElement
Represent a bind parameter.
Public constructor is the bindparam() function.
Implement the == operator.
In a column context, produces the clause a = b. If the target is None, produces a IS NULL.
Construct a BindParameter.
Parameters: |
|
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Implement the <= operator.
In a column context, produces the clause a <= b.
Implement the < operator.
In a column context, produces the clause a < b.
Implement the != operator.
In a column context, produces the clause a != b. If the target is None, produces a IS NOT NULL.
provides a constant ‘anonymous label’ for this ColumnElement.
This is a label() expression which will be named at compile time. The same label() is returned each time anon_label is called so that expressions can reference anon_label multiple times, producing the same label name at compile time.
the compiler uses this function automatically at compile time for expressions that are known to be ‘unnamed’ like binary expressions and function calls.
Produce a asc() clause against the parent object.
Produce a between() clause against the parent object, given the lower and upper range.
Produce a collate() clause against the parent object, given the collation string.
Compare this BindParameter to the given clause.
Compile this SQL expression.
The return value is a Compiled object. Calling str() or unicode() on the returned value will yield a string representation of the result. The Compiled object also can return a dictionary of bind parameter names and values using the params accessor.
Parameters: |
|
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Implement the ‘concat’ operator.
In a column context, produces the clause a || b, or uses the concat() operator on MySQL.
Implement the ‘contains’ operator.
In a column context, produces the clause LIKE '%<other>%'
Produce a desc() clause against the parent object.
Produce a distinct() clause against the parent object.
Return the value of this bound parameter, taking into account if the callable parameter was set.
The callable value will be evaluated and returned if present, else value.
Implement the ‘endswith’ operator.
In a column context, produces the clause LIKE '%<other>'
Return a column expression.
Part of the inspection interface; returns self.
Return immediate child elements of this ClauseElement.
This is used for visit traversal.
**kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).
Implement the ilike operator.
In a column context, produces the clause a ILIKE other.
Implement the in operator.
In a column context, produces the clause a IN other. “other” may be a tuple/list of column expressions, or a select() construct.
Implement the IS operator.
Normally, IS is generated automatically when comparing to a value of None, which resolves to NULL. However, explicit usage of IS may be desirable if comparing to boolean values on certain platforms.
New in version 0.7.9.
See also
Implement the IS NOT operator.
Normally, IS NOT is generated automatically when comparing to a value of None, which resolves to NULL. However, explicit usage of IS NOT may be desirable if comparing to boolean values on certain platforms.
New in version 0.7.9.
See also
Produce a column label, i.e. <columnname> AS <name>.
This is a shortcut to the label() function.
if ‘name’ is None, an anonymous label name will be generated.
Implement the like operator.
In a column context, produces the clause a LIKE other.
Implements the ‘match’ operator.
In a column context, this produces a MATCH clause, i.e. MATCH '<other>'. The allowed contents of other are database backend specific.
implement the NOT ILIKE operator.
This is equivalent to using negation with ColumnOperators.ilike(), i.e. ~x.ilike(y).
New in version 0.8.
See also
implement the NOT IN operator.
This is equivalent to using negation with ColumnOperators.in_(), i.e. ~x.in_(y).
New in version 0.8.
See also
implement the NOT LIKE operator.
This is equivalent to using negation with ColumnOperators.like(), i.e. ~x.like(y).
New in version 0.8.
See also
Produce a nullsfirst() clause against the parent object.
Produce a nullslast() clause against the parent object.
produce a generic operator function.
e.g.:
somecolumn.op("*")(5)
produces:
somecolumn * 5
This function can also be used to make bitwise operators explicit. For example:
somecolumn.op('&')(0xff)
is a bitwise AND of the value in somecolumn.
Parameters: |
|
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Return a copy with bindparam() elements replaced.
Returns a copy of this ClauseElement with bindparam() elements replaced with values taken from the given dictionary:
>>> clause = column('x') + bindparam('foo')
>>> print clause.compile().params
{'foo':None}
>>> print clause.params({'foo':7}).compile().params
{'foo':7}
Apply a ‘grouping’ to this ClauseElement.
This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by select() constructs when placed into the FROM clause of another select(). (Note that subqueries should be normally created using the Select.alias() method, as many platforms require nested SELECT statements to be named).
As expressions are composed together, the application of self_group() is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like x OR (y AND z) - AND takes precedence over OR.
The base self_group() method of ClauseElement just returns self.
Return True if the given ColumnElement has a common ancestor to this ColumnElement.
Implement the startwith operator.
In a column context, produces the clause LIKE '<other>%'
Return a copy with bindparam() elements replaced.
Same functionality as params(), except adds unique=True to affected bind parameters so that multiple statements can be used.
Bases: sqlalchemy.sql.visitors.Visitable
Base class for elements of a programmatically constructed SQL expression.
Compare this ClauseElement to the given ClauseElement.
Subclasses should override the default behavior, which is a straight identity comparison.
**kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see ColumnElement)
Compile this SQL expression.
The return value is a Compiled object. Calling str() or unicode() on the returned value will yield a string representation of the result. The Compiled object also can return a dictionary of bind parameter names and values using the params accessor.
Parameters: |
|
---|
Return immediate child elements of this ClauseElement.
This is used for visit traversal.
**kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).
Return a copy with bindparam() elements replaced.
Returns a copy of this ClauseElement with bindparam() elements replaced with values taken from the given dictionary:
>>> clause = column('x') + bindparam('foo')
>>> print clause.compile().params
{'foo':None}
>>> print clause.params({'foo':7}).compile().params
{'foo':7}
Apply a ‘grouping’ to this ClauseElement.
This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by select() constructs when placed into the FROM clause of another select(). (Note that subqueries should be normally created using the Select.alias() method, as many platforms require nested SELECT statements to be named).
As expressions are composed together, the application of self_group() is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like x OR (y AND z) - AND takes precedence over OR.
The base self_group() method of ClauseElement just returns self.
Return a copy with bindparam() elements replaced.
Same functionality as params(), except adds unique=True to affected bind parameters so that multiple statements can be used.
Bases: sqlalchemy.sql.expression.ClauseElement
Describe a list of clauses, separated by an operator.
By default, is comma-separated, such as a column listing.
Compare this ClauseList to the given ClauseList, including a comparison of all the clause items.
Bases: sqlalchemy.sql.expression.Immutable, sqlalchemy.sql.expression.ColumnElement
Represents a generic column expression from any textual string.
This includes columns associated with tables, aliases and select statements, but also any arbitrary text. May or may not be bound to an underlying Selectable.
ColumnClause is constructed by itself typically via the column() function. It may be placed directly into constructs such as select() constructs:
from sqlalchemy.sql import column, select
c1, c2 = column("c1"), column("c2")
s = select([c1, c2]).where(c1==5)
There is also a variant on column() known as literal_column() - the difference is that in the latter case, the string value is assumed to be an exact expression, rather than a column name, so that no quoting rules or similar are applied:
from sqlalchemy.sql import literal_column, select
s = select([literal_column("5 + 7")])
ColumnClause can also be used in a table-like fashion by combining the column() function with the table() function, to produce a “lightweight” form of table metadata:
from sqlalchemy.sql import table, column
user = table("user",
column("id"),
column("name"),
column("description"),
)
The above construct can be created in an ad-hoc fashion and is not associated with any schema.MetaData, unlike it’s more full fledged schema.Table counterpart.
Parameters: |
|
---|
Implement the == operator.
In a column context, produces the clause a = b. If the target is None, produces a IS NULL.
Implement the <= operator.
In a column context, produces the clause a <= b.
Implement the < operator.
In a column context, produces the clause a < b.
Implement the != operator.
In a column context, produces the clause a != b. If the target is None, produces a IS NOT NULL.
provides a constant ‘anonymous label’ for this ColumnElement.
This is a label() expression which will be named at compile time. The same label() is returned each time anon_label is called so that expressions can reference anon_label multiple times, producing the same label name at compile time.
the compiler uses this function automatically at compile time for expressions that are known to be ‘unnamed’ like binary expressions and function calls.
Produce a asc() clause against the parent object.
Produce a between() clause against the parent object, given the lower and upper range.
Produce a collate() clause against the parent object, given the collation string.
Compare this ColumnElement to another.
Special arguments understood:
Parameters: |
|
---|
Compile this SQL expression.
The return value is a Compiled object. Calling str() or unicode() on the returned value will yield a string representation of the result. The Compiled object also can return a dictionary of bind parameter names and values using the params accessor.
Parameters: |
|
---|
Implement the ‘concat’ operator.
In a column context, produces the clause a || b, or uses the concat() operator on MySQL.
Implement the ‘contains’ operator.
In a column context, produces the clause LIKE '%<other>%'
Produce a desc() clause against the parent object.
Produce a distinct() clause against the parent object.
Implement the ‘endswith’ operator.
In a column context, produces the clause LIKE '%<other>'
Return a column expression.
Part of the inspection interface; returns self.
Return immediate child elements of this ClauseElement.
This is used for visit traversal.
**kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).
Implement the ilike operator.
In a column context, produces the clause a ILIKE other.
Implement the in operator.
In a column context, produces the clause a IN other. “other” may be a tuple/list of column expressions, or a select() construct.
Implement the IS operator.
Normally, IS is generated automatically when comparing to a value of None, which resolves to NULL. However, explicit usage of IS may be desirable if comparing to boolean values on certain platforms.
New in version 0.7.9.
See also
Implement the IS NOT operator.
Normally, IS NOT is generated automatically when comparing to a value of None, which resolves to NULL. However, explicit usage of IS NOT may be desirable if comparing to boolean values on certain platforms.
New in version 0.7.9.
See also
Produce a column label, i.e. <columnname> AS <name>.
This is a shortcut to the label() function.
if ‘name’ is None, an anonymous label name will be generated.
Implement the like operator.
In a column context, produces the clause a LIKE other.
Implements the ‘match’ operator.
In a column context, this produces a MATCH clause, i.e. MATCH '<other>'. The allowed contents of other are database backend specific.
implement the NOT ILIKE operator.
This is equivalent to using negation with ColumnOperators.ilike(), i.e. ~x.ilike(y).
New in version 0.8.
See also
implement the NOT IN operator.
This is equivalent to using negation with ColumnOperators.in_(), i.e. ~x.in_(y).
New in version 0.8.
See also
implement the NOT LIKE operator.
This is equivalent to using negation with ColumnOperators.like(), i.e. ~x.like(y).
New in version 0.8.
See also
Produce a nullsfirst() clause against the parent object.
Produce a nullslast() clause against the parent object.
produce a generic operator function.
e.g.:
somecolumn.op("*")(5)
produces:
somecolumn * 5
This function can also be used to make bitwise operators explicit. For example:
somecolumn.op('&')(0xff)
is a bitwise AND of the value in somecolumn.
Parameters: |
|
---|
Apply a ‘grouping’ to this ClauseElement.
This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by select() constructs when placed into the FROM clause of another select(). (Note that subqueries should be normally created using the Select.alias() method, as many platforms require nested SELECT statements to be named).
As expressions are composed together, the application of self_group() is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like x OR (y AND z) - AND takes precedence over OR.
The base self_group() method of ClauseElement just returns self.
Return True if the given ColumnElement has a common ancestor to this ColumnElement.
Implement the startwith operator.
In a column context, produces the clause LIKE '<other>%'
Bases: sqlalchemy.util._collections.OrderedProperties
An ordered dictionary that stores a list of ColumnElement instances.
Overrides the __eq__() method to produce SQL clauses between sets of correlated columns.
Add a column to this collection.
The key attribute of the column will be used as the hash key for this dictionary.
add the given column to this collection, removing unaliased versions of this column as well as existing columns with the same key.
e.g.:
t = Table('sometable', metadata, Column('col1', Integer)) t.columns.replace(Column('col1', Integer, key='columnone'))will remove the original ‘col1’ from the collection, and add the new column under the name ‘columnname’.
Used by schema.Column to override columns during table reflection.
Bases: sqlalchemy.sql.expression.ClauseElement, sqlalchemy.sql.operators.ColumnOperators
Represent a column-oriented SQL expression suitable for usage in the “columns” clause, WHERE clause etc. of a statement.
While the most familiar kind of ColumnElement is the Column object, ColumnElement serves as the basis for any unit that may be present in a SQL expression, including the expressions themselves, SQL functions, bound parameters, literal expressions, keywords such as NULL, etc. ColumnElement is the ultimate base class for all such elements.
A ColumnElement provides the ability to generate new ColumnElement objects using Python expressions. This means that Python operators such as ==, != and < are overloaded to mimic SQL operations, and allow the instantiation of further ColumnElement instances which are composed from other, more fundamental ColumnElement objects. For example, two ColumnClause objects can be added together with the addition operator + to produce a BinaryExpression. Both ColumnClause and BinaryExpression are subclasses of ColumnElement:
>>> from sqlalchemy.sql import column
>>> column('a') + column('b')
<sqlalchemy.sql.expression.BinaryExpression object at 0x101029dd0>
>>> print column('a') + column('b')
a + b
ColumnElement supports the ability to be a proxy element, which indicates that the ColumnElement may be associated with a Selectable which was derived from another Selectable. An example of a “derived” Selectable is an Alias of a Table. For the ambitious, an in-depth discussion of this concept can be found at Expression Transformations.
Implement the == operator.
In a column context, produces the clause a = b. If the target is None, produces a IS NULL.
x.__init__(...) initializes x; see help(type(x)) for signature
Implement the <= operator.
In a column context, produces the clause a <= b.
Implement the < operator.
In a column context, produces the clause a < b.
Implement the != operator.
In a column context, produces the clause a != b. If the target is None, produces a IS NOT NULL.
provides a constant ‘anonymous label’ for this ColumnElement.
This is a label() expression which will be named at compile time. The same label() is returned each time anon_label is called so that expressions can reference anon_label multiple times, producing the same label name at compile time.
the compiler uses this function automatically at compile time for expressions that are known to be ‘unnamed’ like binary expressions and function calls.
Produce a asc() clause against the parent object.
Produce a between() clause against the parent object, given the lower and upper range.
Produce a collate() clause against the parent object, given the collation string.
Compare this ColumnElement to another.
Special arguments understood:
Parameters: |
|
---|
Compile this SQL expression.
The return value is a Compiled object. Calling str() or unicode() on the returned value will yield a string representation of the result. The Compiled object also can return a dictionary of bind parameter names and values using the params accessor.
Parameters: |
|
---|
Implement the ‘concat’ operator.
In a column context, produces the clause a || b, or uses the concat() operator on MySQL.
Implement the ‘contains’ operator.
In a column context, produces the clause LIKE '%<other>%'
Produce a desc() clause against the parent object.
Produce a distinct() clause against the parent object.
Implement the ‘endswith’ operator.
In a column context, produces the clause LIKE '%<other>'
Return a column expression.
Part of the inspection interface; returns self.
Return immediate child elements of this ClauseElement.
This is used for visit traversal.
**kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).
Implement the ilike operator.
In a column context, produces the clause a ILIKE other.
Implement the in operator.
In a column context, produces the clause a IN other. “other” may be a tuple/list of column expressions, or a select() construct.
Implement the IS operator.
Normally, IS is generated automatically when comparing to a value of None, which resolves to NULL. However, explicit usage of IS may be desirable if comparing to boolean values on certain platforms.
New in version 0.7.9.
See also
Implement the IS NOT operator.
Normally, IS NOT is generated automatically when comparing to a value of None, which resolves to NULL. However, explicit usage of IS NOT may be desirable if comparing to boolean values on certain platforms.
New in version 0.7.9.
See also
Produce a column label, i.e. <columnname> AS <name>.
This is a shortcut to the label() function.
if ‘name’ is None, an anonymous label name will be generated.
Implement the like operator.
In a column context, produces the clause a LIKE other.
Implements the ‘match’ operator.
In a column context, this produces a MATCH clause, i.e. MATCH '<other>'. The allowed contents of other are database backend specific.
implement the NOT ILIKE operator.
This is equivalent to using negation with ColumnOperators.ilike(), i.e. ~x.ilike(y).
New in version 0.8.
See also
implement the NOT IN operator.
This is equivalent to using negation with ColumnOperators.in_(), i.e. ~x.in_(y).
New in version 0.8.
See also
implement the NOT LIKE operator.
This is equivalent to using negation with ColumnOperators.like(), i.e. ~x.like(y).
New in version 0.8.
See also
Produce a nullsfirst() clause against the parent object.
Produce a nullslast() clause against the parent object.
produce a generic operator function.
e.g.:
somecolumn.op("*")(5)
produces:
somecolumn * 5
This function can also be used to make bitwise operators explicit. For example:
somecolumn.op('&')(0xff)
is a bitwise AND of the value in somecolumn.
Parameters: |
|
---|
Return a copy with bindparam() elements replaced.
Returns a copy of this ClauseElement with bindparam() elements replaced with values taken from the given dictionary:
>>> clause = column('x') + bindparam('foo')
>>> print clause.compile().params
{'foo':None}
>>> print clause.params({'foo':7}).compile().params
{'foo':7}
Apply a ‘grouping’ to this ClauseElement.
This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by select() constructs when placed into the FROM clause of another select(). (Note that subqueries should be normally created using the Select.alias() method, as many platforms require nested SELECT statements to be named).
As expressions are composed together, the application of self_group() is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like x OR (y AND z) - AND takes precedence over OR.
The base self_group() method of ClauseElement just returns self.
Return True if the given ColumnElement has a common ancestor to this ColumnElement.
Implement the startwith operator.
In a column context, produces the clause LIKE '<other>%'
Return a copy with bindparam() elements replaced.
Same functionality as params(), except adds unique=True to affected bind parameters so that multiple statements can be used.
Bases: sqlalchemy.sql.operators.Operators
Defines boolean, comparison, and other operators for ColumnElement expressions.
By default, all methods call down to operate() or reverse_operate(), passing in the appropriate operator function from the Python builtin operator module or a SQLAlchemy-specific operator function from sqlalchemy.expression.operators. For example the __eq__ function:
def __eq__(self, other):
return self.operate(operators.eq, other)
Where operators.eq is essentially:
def eq(a, b):
return a == b
The core column expression unit ColumnElement overrides Operators.operate() and others to return further ColumnElement constructs, so that the == operation above is replaced by a clause construct.
See also:
Redefining and Creating New Operators
Implement the + operator.
In a column context, produces the clause a + b if the parent object has non-string affinity. If the parent object has a string affinity, produces the concatenation operator, a || b - see ColumnOperators.concat().
Implement the & operator.
When used with SQL expressions, results in an AND operation, equivalent to and_(), that is:
a & b
is equivalent to:
from sqlalchemy import and_
and_(a, b)
Care should be taken when using & regarding operator precedence; the & operator has the highest precedence. The operands should be enclosed in parenthesis if they contain further sub expressions:
(a == 2) & (b == 4)
x.__delattr__(‘name’) <==> del x.name
Implement the / operator.
In a column context, produces the clause a / b.
Implement the == operator.
In a column context, produces the clause a = b. If the target is None, produces a IS NULL.
default object formatter
Implement the >= operator.
In a column context, produces the clause a >= b.
x.__getattribute__(‘name’) <==> x.name
Implement the [] operator.
This can be used by some database-specific types such as Postgresql ARRAY and HSTORE.
Implement the > operator.
In a column context, produces the clause a > b.
x.__hash__() <==> hash(x)
x.__init__(...) initializes x; see help(type(x)) for signature
Implement the ~ operator.
When used with SQL expressions, results in a NOT operation, equivalent to not_(), that is:
~a
is equivalent to:
from sqlalchemy import not_
not_(a)
Block calls to list() from calling __getitem__() endlessly.
Implement the <= operator.
In a column context, produces the clause a <= b.
implement the << operator.
Not used by SQLAlchemy core, this is provided for custom operator systems which want to use << as an extension point.
Implement the < operator.
In a column context, produces the clause a < b.
Implement the % operator.
In a column context, produces the clause a % b.
Implement the * operator.
In a column context, produces the clause a * b.
Implement the != operator.
In a column context, produces the clause a != b. If the target is None, produces a IS NOT NULL.
Implement the - operator.
In a column context, produces the clause -a.
Implement the | operator.
When used with SQL expressions, results in an OR operation, equivalent to or_(), that is:
a | b
is equivalent to:
from sqlalchemy import or_
or_(a, b)
Care should be taken when using | regarding operator precedence; the | operator has the highest precedence. The operands should be enclosed in parenthesis if they contain further sub expressions:
(a == 2) | (b == 4)
Implement the + operator in reverse.
Implement the / operator in reverse.
helper for pickle
helper for pickle
x.__repr__() <==> repr(x)
Implement the * operator in reverse.
implement the >> operator.
Not used by SQLAlchemy core, this is provided for custom operator systems which want to use >> as an extension point.
Implement the - operator in reverse.
Implement the // operator in reverse.
x.__setattr__(‘name’, value) <==> x.name = value
size of object in memory, in bytes
x.__str__() <==> str(x)
Implement the - operator.
In a column context, produces the clause a - b.
Abstract classes can override this to customize issubclass().
This is invoked early on by abc.ABCMeta.__subclasscheck__(). It should return True, False or NotImplemented. If it returns NotImplemented, the normal algorithm is used. Otherwise, it overrides the normal algorithm (and the outcome is cached).
Implement the // operator.
In a column context, produces the clause a / b.
list of weak references to the object (if defined)
Produce a between() clause against the parent object, given the lower and upper range.
Produce a collate() clause against the parent object, given the collation string.
Implement the ‘concat’ operator.
In a column context, produces the clause a || b, or uses the concat() operator on MySQL.
Implement the ‘contains’ operator.
In a column context, produces the clause LIKE '%<other>%'
Produce a distinct() clause against the parent object.
Implement the ‘endswith’ operator.
In a column context, produces the clause LIKE '%<other>'
Implement the ilike operator.
In a column context, produces the clause a ILIKE other.
Implement the in operator.
In a column context, produces the clause a IN other. “other” may be a tuple/list of column expressions, or a select() construct.
Implement the IS operator.
Normally, IS is generated automatically when comparing to a value of None, which resolves to NULL. However, explicit usage of IS may be desirable if comparing to boolean values on certain platforms.
New in version 0.7.9.
See also
Implement the IS NOT operator.
Normally, IS NOT is generated automatically when comparing to a value of None, which resolves to NULL. However, explicit usage of IS NOT may be desirable if comparing to boolean values on certain platforms.
New in version 0.7.9.
See also
Implement the like operator.
In a column context, produces the clause a LIKE other.
Implements the ‘match’ operator.
In a column context, this produces a MATCH clause, i.e. MATCH '<other>'. The allowed contents of other are database backend specific.
implement the NOT ILIKE operator.
This is equivalent to using negation with ColumnOperators.ilike(), i.e. ~x.ilike(y).
New in version 0.8.
See also
implement the NOT IN operator.
This is equivalent to using negation with ColumnOperators.in_(), i.e. ~x.in_(y).
New in version 0.8.
See also
implement the NOT LIKE operator.
This is equivalent to using negation with ColumnOperators.like(), i.e. ~x.like(y).
New in version 0.8.
See also
Produce a nullsfirst() clause against the parent object.
Produce a nullslast() clause against the parent object.
produce a generic operator function.
e.g.:
somecolumn.op("*")(5)
produces:
somecolumn * 5
This function can also be used to make bitwise operators explicit. For example:
somecolumn.op('&')(0xff)
is a bitwise AND of the value in somecolumn.
Parameters: |
|
---|
Operate on an argument.
This is the lowest level of operation, raises NotImplementedError by default.
Overriding this on a subclass can allow common behavior to be applied to all operations. For example, overriding ColumnOperators to apply func.lower() to the left and right side:
class MyComparator(ColumnOperators):
def operate(self, op, other):
return op(func.lower(self), func.lower(other))
Parameters: |
|
---|
Reverse operate on an argument.
Usage is the same as operate().
Implement the startwith operator.
In a column context, produces the clause LIKE '<other>%'
Hack, allows datetime objects to be compared on the LHS.
Bases: sqlalchemy.sql.expression.SelectBase
Forms the basis of UNION, UNION ALL, and other SELECT-based set operations.
return an alias of this FromClause.
This is shorthand for calling:
from sqlalchemy import alias
a = alias(self, name=name)
See alias() for details.
Append the given GROUP BY criterion applied to this selectable.
The criterion will be appended to any pre-existing GROUP BY criterion.
Append the given ORDER BY criterion applied to this selectable.
The criterion will be appended to any pre-existing ORDER BY criterion.
return a new selectable with the ‘use_labels’ flag set to True.
This will result in column expressions being generated using labels against their table name, such as “SELECT somecolumn AS tablename_somecolumn”. This allows selectables which contain multiple FROM clauses to produce a unique set of column names regardless of name conflicts among the individual FROM clauses.
return a ‘scalar’ representation of this selectable, which can be used as a column expression.
Typically, a select statement which has only one column in its columns clause is eligible to be used as a scalar expression.
The returned object is an instance of ScalarSelect.
return a new selectable with the ‘autocommit’ flag set to
Deprecated since version 0.6: autocommit() is deprecated. Use Executable.execution_options() with the ‘autocommit’ flag.
True.
An alias for the columns attribute.
A named-based collection of ColumnElement objects maintained by this FromClause.
The columns, or c collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:
select([mytable]).where(mytable.c.somecolumn == 5)
Compare this ClauseElement to the given ClauseElement.
Subclasses should override the default behavior, which is a straight identity comparison.
**kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see ColumnElement)
Compile this SQL expression.
The return value is a Compiled object. Calling str() or unicode() on the returned value will yield a string representation of the result. The Compiled object also can return a dictionary of bind parameter names and values using the params accessor.
Parameters: |
|
---|
Return corresponding_column for the given column, or if None search for a match in the given dictionary.
Given a ColumnElement, return the exported ColumnElement object from this Selectable which corresponds to that original Column via a common ancestor column.
Parameters: |
|
---|
the given ColumnElement, if the given ColumnElement is actually present within a sub-element of this FromClause. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this FromClause.
return a SELECT COUNT generated against this FromClause.
Return a new CTE, or Common Table Expression instance.
Common table expressions are a SQL standard whereby SELECT statements can draw upon secondary statements specified along with the primary statement, using a clause called “WITH”. Special semantics regarding UNION can also be employed to allow “recursive” queries, where a SELECT statement can draw upon the set of rows that have previously been selected.
SQLAlchemy detects CTE objects, which are treated similarly to Alias objects, as special elements to be delivered to the FROM clause of the statement as well as to a WITH clause at the top of the statement.
New in version 0.7.6.
Parameters: |
|
---|
The following examples illustrate two examples from Postgresql’s documentation at http://www.postgresql.org/docs/8.4/static/queries-with.html.
Example 1, non recursive:
from sqlalchemy import Table, Column, String, Integer, MetaData, \
select, func
metadata = MetaData()
orders = Table('orders', metadata,
Column('region', String),
Column('amount', Integer),
Column('product', String),
Column('quantity', Integer)
)
regional_sales = select([
orders.c.region,
func.sum(orders.c.amount).label('total_sales')
]).group_by(orders.c.region).cte("regional_sales")
top_regions = select([regional_sales.c.region]).\
where(
regional_sales.c.total_sales >
select([
func.sum(regional_sales.c.total_sales)/10
])
).cte("top_regions")
statement = select([
orders.c.region,
orders.c.product,
func.sum(orders.c.quantity).label("product_units"),
func.sum(orders.c.amount).label("product_sales")
]).where(orders.c.region.in_(
select([top_regions.c.region])
)).group_by(orders.c.region, orders.c.product)
result = conn.execute(statement).fetchall()
Example 2, WITH RECURSIVE:
from sqlalchemy import Table, Column, String, Integer, MetaData, \
select, func
metadata = MetaData()
parts = Table('parts', metadata,
Column('part', String),
Column('sub_part', String),
Column('quantity', Integer),
)
included_parts = select([
parts.c.sub_part,
parts.c.part,
parts.c.quantity]).\
where(parts.c.part=='our part').\
cte(recursive=True)
incl_alias = included_parts.alias()
parts_alias = parts.alias()
included_parts = included_parts.union_all(
select([
parts_alias.c.part,
parts_alias.c.sub_part,
parts_alias.c.quantity
]).
where(parts_alias.c.part==incl_alias.c.sub_part)
)
statement = select([
included_parts.c.sub_part,
func.sum(included_parts.c.quantity).
label('total_quantity')
]). select_from(included_parts.join(parts,
included_parts.c.part==parts.c.part)).\
group_by(included_parts.c.sub_part)
result = conn.execute(statement).fetchall()
See also:
orm.query.Query.cte() - ORM version of SelectBase.cte().
a brief description of this FromClause.
Used primarily for error message formatting.
Compile and execute this Executable.
Set non-SQL options for the statement which take effect during execution.
Execution options can be set on a per-statement or per Connection basis. Additionally, the Engine and ORM Query objects provide access to execution options which they in turn configure upon connections.
The execution_options() method is generative. A new instance of this statement is returned that contains the options:
statement = select([table.c.x, table.c.y])
statement = statement.execution_options(autocommit=True)
Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See Connection.execution_options() for a full list of possible options.
See also:
Return the collection of ForeignKey objects which this FromClause references.
return a new selectable with the given list of GROUP BY criterion applied.
The criterion will be appended to any pre-existing GROUP BY criterion.
return a join of this FromClause against another FromClause.
return a ‘scalar’ representation of this selectable, embedded as a subquery with a label.
See also as_scalar().
return a new selectable with the given LIMIT criterion applied.
return a new selectable with the given OFFSET criterion applied.
return a new selectable with the given list of ORDER BY criterion applied.
The criterion will be appended to any pre-existing ORDER BY criterion.
return an outer join of this FromClause against another FromClause.
Return a copy with bindparam() elements replaced.
Returns a copy of this ClauseElement with bindparam() elements replaced with values taken from the given dictionary:
>>> clause = column('x') + bindparam('foo')
>>> print clause.compile().params
{'foo':None}
>>> print clause.params({'foo':7}).compile().params
{'foo':7}
Return the collection of Column objects which comprise the primary key of this FromClause.
replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this FromClause.
Compile and execute this Executable, returning the result’s scalar representation.
return a SELECT of this FromClause.
Return a copy with bindparam() elements replaced.
Same functionality as params(), except adds unique=True to affected bind parameters so that multiple statements can be used.
Represent a ‘custom’ operator.
custom_op is normally instantitated when the ColumnOperators.op() method is used to create a custom operator callable. The class can also be used directly when programmatically constructing expressions. E.g. to represent the “factorial” operation:
from sqlalchemy.sql import UnaryExpression
from sqlalchemy.sql import operators
from sqlalchemy import Numeric
unary = UnaryExpression(table.c.somecolumn,
modifier=operators.custom_op("!"),
type_=Numeric)
Bases: sqlalchemy.sql.expression.Alias
Represent a Common Table Expression.
The CTE object is obtained using the SelectBase.cte() method from any selectable. See that method for complete examples.
New in version 0.7.6.
An alias for the columns attribute.
A named-based collection of ColumnElement objects maintained by this FromClause.
The columns, or c collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:
select([mytable]).where(mytable.c.somecolumn == 5)
Compare this ClauseElement to the given ClauseElement.
Subclasses should override the default behavior, which is a straight identity comparison.
**kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see ColumnElement)
Compile this SQL expression.
The return value is a Compiled object. Calling str() or unicode() on the returned value will yield a string representation of the result. The Compiled object also can return a dictionary of bind parameter names and values using the params accessor.
Parameters: |
|
---|
Return corresponding_column for the given column, or if None search for a match in the given dictionary.
Given a ColumnElement, return the exported ColumnElement object from this Selectable which corresponds to that original Column via a common ancestor column.
Parameters: |
|
---|
the given ColumnElement, if the given ColumnElement is actually present within a sub-element of this FromClause. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this FromClause.
return a SELECT COUNT generated against this FromClause.
Return the collection of ForeignKey objects which this FromClause references.
return a join of this FromClause against another FromClause.
return an outer join of this FromClause against another FromClause.
Return a copy with bindparam() elements replaced.
Returns a copy of this ClauseElement with bindparam() elements replaced with values taken from the given dictionary:
>>> clause = column('x') + bindparam('foo')
>>> print clause.compile().params
{'foo':None}
>>> print clause.params({'foo':7}).compile().params
{'foo':7}
Return the collection of Column objects which comprise the primary key of this FromClause.
replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this FromClause.
return a SELECT of this FromClause.
Apply a ‘grouping’ to this ClauseElement.
This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by select() constructs when placed into the FROM clause of another select(). (Note that subqueries should be normally created using the Select.alias() method, as many platforms require nested SELECT statements to be named).
As expressions are composed together, the application of self_group() is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like x OR (y AND z) - AND takes precedence over OR.
The base self_group() method of ClauseElement just returns self.
Return a copy with bindparam() elements replaced.
Same functionality as params(), except adds unique=True to affected bind parameters so that multiple statements can be used.
Bases: sqlalchemy.sql.expression.UpdateBase
Represent a DELETE construct.
The Delete object is created using the delete() function.
Return a ‘bind’ linked to this UpdateBase or a Table associated with it.
Compare this ClauseElement to the given ClauseElement.
Subclasses should override the default behavior, which is a straight identity comparison.
**kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see ColumnElement)
Compile this SQL expression.
The return value is a Compiled object. Calling str() or unicode() on the returned value will yield a string representation of the result. The Compiled object also can return a dictionary of bind parameter names and values using the params accessor.
Parameters: |
|
---|
Compile and execute this Executable.
Set non-SQL options for the statement which take effect during execution.
Execution options can be set on a per-statement or per Connection basis. Additionally, the Engine and ORM Query objects provide access to execution options which they in turn configure upon connections.
The execution_options() method is generative. A new instance of this statement is returned that contains the options:
statement = select([table.c.x, table.c.y])
statement = statement.execution_options(autocommit=True)
Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See Connection.execution_options() for a full list of possible options.
See also:
Set the parameters for the statement.
This method raises NotImplementedError on the base class, and is overridden by ValuesBase to provide the SET/VALUES clause of UPDATE and INSERT.
Add one or more expressions following the statement keyword, i.e. SELECT, INSERT, UPDATE, or DELETE. Generative.
This is used to support backend-specific prefix keywords such as those provided by MySQL.
E.g.:
stmt = table.insert().prefix_with("LOW_PRIORITY", dialect="mysql")
Multiple prefixes can be specified by multiple calls to prefix_with().
Parameters: |
|
---|
Add a RETURNING or equivalent clause to this statement.
The given list of columns represent columns within the table that is the target of the INSERT, UPDATE, or DELETE. Each element can be any column expression. Table objects will be expanded into their individual columns.
Upon compilation, a RETURNING clause, or database equivalent, will be rendered within the statement. For INSERT and UPDATE, the values are the newly inserted/updated values. For DELETE, the values are those of the rows which were deleted.
Upon execution, the values of the columns to be returned are made available via the result set and can be iterated using fetchone() and similar. For DBAPIs which do not natively support returning values (i.e. cx_oracle), SQLAlchemy will approximate this behavior at the result level so that a reasonable amount of behavioral neutrality is provided.
Note that not all databases/DBAPIs support RETURNING. For those backends with no support, an exception is raised upon compilation and/or execution. For those who do support it, the functionality across backends varies greatly, including restrictions on executemany() and other statements which return multiple rows. Please read the documentation notes for the database in use in order to determine the availability of RETURNING.
Compile and execute this Executable, returning the result’s scalar representation.
Apply a ‘grouping’ to this ClauseElement.
This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by select() constructs when placed into the FROM clause of another select(). (Note that subqueries should be normally created using the Select.alias() method, as many platforms require nested SELECT statements to be named).
As expressions are composed together, the application of self_group() is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like x OR (y AND z) - AND takes precedence over OR.
The base self_group() method of ClauseElement just returns self.
Return a copy with bindparam() elements replaced.
Same functionality as params(), except adds unique=True to affected bind parameters so that multiple statements can be used.
Add the given WHERE clause to a newly returned delete construct.
Add a table hint for a single table to this INSERT/UPDATE/DELETE statement.
Note
UpdateBase.with_hint() currently applies only to Microsoft SQL Server. For MySQL INSERT/UPDATE/DELETE hints, use UpdateBase.prefix_with().
The text of the hint is rendered in the appropriate location for the database backend in use, relative to the Table that is the subject of this statement, or optionally to that of the given Table passed as the selectable argument.
The dialect_name option will limit the rendering of a particular hint to a particular backend. Such as, to add a hint that only takes effect for SQL Server:
mytable.insert().with_hint("WITH (PAGLOCK)", dialect_name="mssql")
New in version 0.7.6.
Parameters: |
|
---|
Bases: sqlalchemy.sql.expression.Generative
Mark a ClauseElement as supporting execution.
Executable is a superclass for all “statement” types of objects, including select(), delete(), update(), insert(), text().
Returns the Engine or Connection to which this Executable is bound, or None if none found.
This is a traversal which checks locally, then checks among the “from” clauses of associated objects until a bound engine or connection is found.
Compile and execute this Executable.
Set non-SQL options for the statement which take effect during execution.
Execution options can be set on a per-statement or per Connection basis. Additionally, the Engine and ORM Query objects provide access to execution options which they in turn configure upon connections.
The execution_options() method is generative. A new instance of this statement is returned that contains the options:
statement = select([table.c.x, table.c.y])
statement = statement.execution_options(autocommit=True)
Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See Connection.execution_options() for a full list of possible options.
See also:
Compile and execute this Executable, returning the result’s scalar representation.
Bases: sqlalchemy.sql.expression.Executable, sqlalchemy.sql.expression.ColumnElement, sqlalchemy.sql.expression.FromClause
Base for SQL function-oriented constructs.
See also:
Function - named SQL function.
func - namespace which produces registered or ad-hoc Function instances.
GenericFunction - allows creation of registered function types.
Implement the == operator.
In a column context, produces the clause a = b. If the target is None, produces a IS NULL.
Construct a FunctionElement.
Implement the <= operator.
In a column context, produces the clause a <= b.
Implement the < operator.
In a column context, produces the clause a < b.
Implement the != operator.
In a column context, produces the clause a != b. If the target is None, produces a IS NOT NULL.
return an alias of this FromClause.
This is shorthand for calling:
from sqlalchemy import alias
a = alias(self, name=name)
See alias() for details.
provides a constant ‘anonymous label’ for this ColumnElement.
This is a label() expression which will be named at compile time. The same label() is returned each time anon_label is called so that expressions can reference anon_label multiple times, producing the same label name at compile time.
the compiler uses this function automatically at compile time for expressions that are known to be ‘unnamed’ like binary expressions and function calls.
Produce a asc() clause against the parent object.
Produce a between() clause against the parent object, given the lower and upper range.
Returns the Engine or Connection to which this Executable is bound, or None if none found.
This is a traversal which checks locally, then checks among the “from” clauses of associated objects until a bound engine or connection is found.
An alias for the columns attribute.
Return the underlying ClauseList which contains the arguments for this FunctionElement.
Produce a collate() clause against the parent object, given the collation string.
Fulfill the ‘columns’ contract of ColumnElement.
Returns a single-element list consisting of this object.
Compare this ColumnElement to another.
Special arguments understood:
Parameters: |
|
---|
Compile this SQL expression.
The return value is a Compiled object. Calling str() or unicode() on the returned value will yield a string representation of the result. The Compiled object also can return a dictionary of bind parameter names and values using the params accessor.
Parameters: |
|
---|
Implement the ‘concat’ operator.
In a column context, produces the clause a || b, or uses the concat() operator on MySQL.
Implement the ‘contains’ operator.
In a column context, produces the clause LIKE '%<other>%'
Return corresponding_column for the given column, or if None search for a match in the given dictionary.
Given a ColumnElement, return the exported ColumnElement object from this Selectable which corresponds to that original Column via a common ancestor column.
Parameters: |
|
---|
the given ColumnElement, if the given ColumnElement is actually present within a sub-element of this FromClause. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this FromClause.
return a SELECT COUNT generated against this FromClause.
Produce a desc() clause against the parent object.
a brief description of this FromClause.
Used primarily for error message formatting.
Produce a distinct() clause against the parent object.
Implement the ‘endswith’ operator.
In a column context, produces the clause LIKE '%<other>'
Execute this FunctionElement against an embedded ‘bind’.
This first calls select() to produce a SELECT construct.
Note that FunctionElement can be passed to the Connectable.execute() method of Connection or Engine.
Set non-SQL options for the statement which take effect during execution.
Execution options can be set on a per-statement or per Connection basis. Additionally, the Engine and ORM Query objects provide access to execution options which they in turn configure upon connections.
The execution_options() method is generative. A new instance of this statement is returned that contains the options:
statement = select([table.c.x, table.c.y])
statement = statement.execution_options(autocommit=True)
Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See Connection.execution_options() for a full list of possible options.
See also:
Return a column expression.
Part of the inspection interface; returns self.
Implement the ilike operator.
In a column context, produces the clause a ILIKE other.
Implement the in operator.
In a column context, produces the clause a IN other. “other” may be a tuple/list of column expressions, or a select() construct.
Implement the IS operator.
Normally, IS is generated automatically when comparing to a value of None, which resolves to NULL. However, explicit usage of IS may be desirable if comparing to boolean values on certain platforms.
New in version 0.7.9.
See also
Return True if this FromClause is ‘derived’ from the given FromClause.
An example would be an Alias of a Table is derived from that Table.
Implement the IS NOT operator.
Normally, IS NOT is generated automatically when comparing to a value of None, which resolves to NULL. However, explicit usage of IS NOT may be desirable if comparing to boolean values on certain platforms.
New in version 0.7.9.
See also
return a join of this FromClause against another FromClause.
Produce a column label, i.e. <columnname> AS <name>.
This is a shortcut to the label() function.
if ‘name’ is None, an anonymous label name will be generated.
Implement the like operator.
In a column context, produces the clause a LIKE other.
Implements the ‘match’ operator.
In a column context, this produces a MATCH clause, i.e. MATCH '<other>'. The allowed contents of other are database backend specific.
implement the NOT ILIKE operator.
This is equivalent to using negation with ColumnOperators.ilike(), i.e. ~x.ilike(y).
New in version 0.8.
See also
implement the NOT IN operator.
This is equivalent to using negation with ColumnOperators.in_(), i.e. ~x.in_(y).
New in version 0.8.
See also
implement the NOT LIKE operator.
This is equivalent to using negation with ColumnOperators.like(), i.e. ~x.like(y).
New in version 0.8.
See also
Produce a nullsfirst() clause against the parent object.
Produce a nullslast() clause against the parent object.
produce a generic operator function.
e.g.:
somecolumn.op("*")(5)
produces:
somecolumn * 5
This function can also be used to make bitwise operators explicit. For example:
somecolumn.op('&')(0xff)
is a bitwise AND of the value in somecolumn.
Parameters: |
|
---|
return an outer join of this FromClause against another FromClause.
Produce an OVER clause against this function.
Used against aggregate or so-called “window” functions, for database backends that support window functions.
The expression:
func.row_number().over(order_by='x')
is shorthand for:
from sqlalchemy import over
over(func.row_number(), order_by='x')
See over() for a full description.
New in version 0.7.
Return a copy with bindparam() elements replaced.
Returns a copy of this ClauseElement with bindparam() elements replaced with values taken from the given dictionary:
>>> clause = column('x') + bindparam('foo')
>>> print clause.compile().params
{'foo':None}
>>> print clause.params({'foo':7}).compile().params
{'foo':7}
replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this FromClause.
Execute this FunctionElement against an embedded ‘bind’ and return a scalar value.
This first calls select() to produce a SELECT construct.
Note that FunctionElement can be passed to the Connectable.scalar() method of Connection or Engine.
Produce a select() construct against this FunctionElement.
This is shorthand for:
s = select([function_element])
Apply a ‘grouping’ to this ClauseElement.
This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by select() constructs when placed into the FROM clause of another select(). (Note that subqueries should be normally created using the Select.alias() method, as many platforms require nested SELECT statements to be named).
As expressions are composed together, the application of self_group() is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like x OR (y AND z) - AND takes precedence over OR.
The base self_group() method of ClauseElement just returns self.
Return True if the given ColumnElement has a common ancestor to this ColumnElement.
Implement the startwith operator.
In a column context, produces the clause LIKE '<other>%'
Return a copy with bindparam() elements replaced.
Same functionality as params(), except adds unique=True to affected bind parameters so that multiple statements can be used.
Bases: sqlalchemy.sql.expression.FunctionElement
Describe a named SQL function.
See the superclass FunctionElement for a description of public methods.
See also:
See also:
func - namespace which produces registered or ad-hoc Function instances.
GenericFunction - allows creation of registered function types.
Implement the == operator.
In a column context, produces the clause a = b. If the target is None, produces a IS NULL.
Construct a Function.
The func construct is normally used to construct new Function instances.
Implement the <= operator.
In a column context, produces the clause a <= b.
Implement the < operator.
In a column context, produces the clause a < b.
Implement the != operator.
In a column context, produces the clause a != b. If the target is None, produces a IS NOT NULL.
return an alias of this FromClause.
This is shorthand for calling:
from sqlalchemy import alias
a = alias(self, name=name)
See alias() for details.
provides a constant ‘anonymous label’ for this ColumnElement.
This is a label() expression which will be named at compile time. The same label() is returned each time anon_label is called so that expressions can reference anon_label multiple times, producing the same label name at compile time.
the compiler uses this function automatically at compile time for expressions that are known to be ‘unnamed’ like binary expressions and function calls.
Produce a asc() clause against the parent object.
Produce a between() clause against the parent object, given the lower and upper range.
Returns the Engine or Connection to which this Executable is bound, or None if none found.
This is a traversal which checks locally, then checks among the “from” clauses of associated objects until a bound engine or connection is found.
An alias for the columns attribute.
Return the underlying ClauseList which contains the arguments for this FunctionElement.
Produce a collate() clause against the parent object, given the collation string.
Fulfill the ‘columns’ contract of ColumnElement.
Returns a single-element list consisting of this object.
Compare this ColumnElement to another.
Special arguments understood:
Parameters: |
|
---|
Compile this SQL expression.
The return value is a Compiled object. Calling str() or unicode() on the returned value will yield a string representation of the result. The Compiled object also can return a dictionary of bind parameter names and values using the params accessor.
Parameters: |
|
---|
Implement the ‘concat’ operator.
In a column context, produces the clause a || b, or uses the concat() operator on MySQL.
Implement the ‘contains’ operator.
In a column context, produces the clause LIKE '%<other>%'
Return corresponding_column for the given column, or if None search for a match in the given dictionary.
Given a ColumnElement, return the exported ColumnElement object from this Selectable which corresponds to that original Column via a common ancestor column.
Parameters: |
|
---|
the given ColumnElement, if the given ColumnElement is actually present within a sub-element of this FromClause. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this FromClause.
return a SELECT COUNT generated against this FromClause.
Produce a desc() clause against the parent object.
a brief description of this FromClause.
Used primarily for error message formatting.
Produce a distinct() clause against the parent object.
Implement the ‘endswith’ operator.
In a column context, produces the clause LIKE '%<other>'
Execute this FunctionElement against an embedded ‘bind’.
This first calls select() to produce a SELECT construct.
Note that FunctionElement can be passed to the Connectable.execute() method of Connection or Engine.
Set non-SQL options for the statement which take effect during execution.
Execution options can be set on a per-statement or per Connection basis. Additionally, the Engine and ORM Query objects provide access to execution options which they in turn configure upon connections.
The execution_options() method is generative. A new instance of this statement is returned that contains the options:
statement = select([table.c.x, table.c.y])
statement = statement.execution_options(autocommit=True)
Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See Connection.execution_options() for a full list of possible options.
See also:
Return a column expression.
Part of the inspection interface; returns self.
Implement the ilike operator.
In a column context, produces the clause a ILIKE other.
Implement the in operator.
In a column context, produces the clause a IN other. “other” may be a tuple/list of column expressions, or a select() construct.
Implement the IS operator.
Normally, IS is generated automatically when comparing to a value of None, which resolves to NULL. However, explicit usage of IS may be desirable if comparing to boolean values on certain platforms.
New in version 0.7.9.
See also
Return True if this FromClause is ‘derived’ from the given FromClause.
An example would be an Alias of a Table is derived from that Table.
Implement the IS NOT operator.
Normally, IS NOT is generated automatically when comparing to a value of None, which resolves to NULL. However, explicit usage of IS NOT may be desirable if comparing to boolean values on certain platforms.
New in version 0.7.9.
See also
return a join of this FromClause against another FromClause.
Produce a column label, i.e. <columnname> AS <name>.
This is a shortcut to the label() function.
if ‘name’ is None, an anonymous label name will be generated.
Implement the like operator.
In a column context, produces the clause a LIKE other.
Implements the ‘match’ operator.
In a column context, this produces a MATCH clause, i.e. MATCH '<other>'. The allowed contents of other are database backend specific.
implement the NOT ILIKE operator.
This is equivalent to using negation with ColumnOperators.ilike(), i.e. ~x.ilike(y).
New in version 0.8.
See also
implement the NOT IN operator.
This is equivalent to using negation with ColumnOperators.in_(), i.e. ~x.in_(y).
New in version 0.8.
See also
implement the NOT LIKE operator.
This is equivalent to using negation with ColumnOperators.like(), i.e. ~x.like(y).
New in version 0.8.
See also
Produce a nullsfirst() clause against the parent object.
Produce a nullslast() clause against the parent object.
produce a generic operator function.
e.g.:
somecolumn.op("*")(5)
produces:
somecolumn * 5
This function can also be used to make bitwise operators explicit. For example:
somecolumn.op('&')(0xff)
is a bitwise AND of the value in somecolumn.
Parameters: |
|
---|
return an outer join of this FromClause against another FromClause.
Produce an OVER clause against this function.
Used against aggregate or so-called “window” functions, for database backends that support window functions.
The expression:
func.row_number().over(order_by='x')
is shorthand for:
from sqlalchemy import over
over(func.row_number(), order_by='x')
See over() for a full description.
New in version 0.7.
Return a copy with bindparam() elements replaced.
Returns a copy of this ClauseElement with bindparam() elements replaced with values taken from the given dictionary:
>>> clause = column('x') + bindparam('foo')
>>> print clause.compile().params
{'foo':None}
>>> print clause.params({'foo':7}).compile().params
{'foo':7}
replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this FromClause.
Execute this FunctionElement against an embedded ‘bind’ and return a scalar value.
This first calls select() to produce a SELECT construct.
Note that FunctionElement can be passed to the Connectable.scalar() method of Connection or Engine.
Produce a select() construct against this FunctionElement.
This is shorthand for:
s = select([function_element])
Apply a ‘grouping’ to this ClauseElement.
This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by select() constructs when placed into the FROM clause of another select(). (Note that subqueries should be normally created using the Select.alias() method, as many platforms require nested SELECT statements to be named).
As expressions are composed together, the application of self_group() is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like x OR (y AND z) - AND takes precedence over OR.
The base self_group() method of ClauseElement just returns self.
Return True if the given ColumnElement has a common ancestor to this ColumnElement.
Implement the startwith operator.
In a column context, produces the clause LIKE '<other>%'
Return a copy with bindparam() elements replaced.
Same functionality as params(), except adds unique=True to affected bind parameters so that multiple statements can be used.
Bases: sqlalchemy.sql.expression.Selectable
Represent an element that can be used within the FROM clause of a SELECT statement.
The most common forms of FromClause are the Table and the select() constructs. Key features common to all FromClause objects include:
return an alias of this FromClause.
This is shorthand for calling:
from sqlalchemy import alias
a = alias(self, name=name)
See alias() for details.
A named-based collection of ColumnElement objects maintained by this FromClause.
The columns, or c collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:
select([mytable]).where(mytable.c.somecolumn == 5)
Return corresponding_column for the given column, or if None search for a match in the given dictionary.
Given a ColumnElement, return the exported ColumnElement object from this Selectable which corresponds to that original Column via a common ancestor column.
Parameters: |
|
---|
the given ColumnElement, if the given ColumnElement is actually present within a sub-element of this FromClause. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this FromClause.
return a SELECT COUNT generated against this FromClause.
a brief description of this FromClause.
Used primarily for error message formatting.
Return the collection of ForeignKey objects which this FromClause references.
Return True if this FromClause is ‘derived’ from the given FromClause.
An example would be an Alias of a Table is derived from that Table.
return a join of this FromClause against another FromClause.
return an outer join of this FromClause against another FromClause.
Return the collection of Column objects which comprise the primary key of this FromClause.
replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this FromClause.
return a SELECT of this FromClause.
Bases: sqlalchemy.sql.expression.ValuesBase
Represent an INSERT construct.
The Insert object is created using the insert() function.
See also:
Return a ‘bind’ linked to this UpdateBase or a Table associated with it.
Compare this ClauseElement to the given ClauseElement.
Subclasses should override the default behavior, which is a straight identity comparison.
**kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see ColumnElement)
Compile this SQL expression.
The return value is a Compiled object. Calling str() or unicode() on the returned value will yield a string representation of the result. The Compiled object also can return a dictionary of bind parameter names and values using the params accessor.
Parameters: |
|
---|
Compile and execute this Executable.
Set non-SQL options for the statement which take effect during execution.
Execution options can be set on a per-statement or per Connection basis. Additionally, the Engine and ORM Query objects provide access to execution options which they in turn configure upon connections.
The execution_options() method is generative. A new instance of this statement is returned that contains the options:
statement = select([table.c.x, table.c.y])
statement = statement.execution_options(autocommit=True)
Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See Connection.execution_options() for a full list of possible options.
See also:
Set the parameters for the statement.
This method raises NotImplementedError on the base class, and is overridden by ValuesBase to provide the SET/VALUES clause of UPDATE and INSERT.
Add one or more expressions following the statement keyword, i.e. SELECT, INSERT, UPDATE, or DELETE. Generative.
This is used to support backend-specific prefix keywords such as those provided by MySQL.
E.g.:
stmt = table.insert().prefix_with("LOW_PRIORITY", dialect="mysql")
Multiple prefixes can be specified by multiple calls to prefix_with().
Parameters: |
|
---|
Add a RETURNING or equivalent clause to this statement.
The given list of columns represent columns within the table that is the target of the INSERT, UPDATE, or DELETE. Each element can be any column expression. Table objects will be expanded into their individual columns.
Upon compilation, a RETURNING clause, or database equivalent, will be rendered within the statement. For INSERT and UPDATE, the values are the newly inserted/updated values. For DELETE, the values are those of the rows which were deleted.
Upon execution, the values of the columns to be returned are made available via the result set and can be iterated using fetchone() and similar. For DBAPIs which do not natively support returning values (i.e. cx_oracle), SQLAlchemy will approximate this behavior at the result level so that a reasonable amount of behavioral neutrality is provided.
Note that not all databases/DBAPIs support RETURNING. For those backends with no support, an exception is raised upon compilation and/or execution. For those who do support it, the functionality across backends varies greatly, including restrictions on executemany() and other statements which return multiple rows. Please read the documentation notes for the database in use in order to determine the availability of RETURNING.
Compile and execute this Executable, returning the result’s scalar representation.
Apply a ‘grouping’ to this ClauseElement.
This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by select() constructs when placed into the FROM clause of another select(). (Note that subqueries should be normally created using the Select.alias() method, as many platforms require nested SELECT statements to be named).
As expressions are composed together, the application of self_group() is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like x OR (y AND z) - AND takes precedence over OR.
The base self_group() method of ClauseElement just returns self.
Return a copy with bindparam() elements replaced.
Same functionality as params(), except adds unique=True to affected bind parameters so that multiple statements can be used.
specify a fixed VALUES clause for an INSERT statement, or the SET clause for an UPDATE.
Note that the Insert and Update constructs support per-execution time formatting of the VALUES and/or SET clauses, based on the arguments passed to Connection.execute(). However, the ValuesBase.values() method can be used to “fix” a particular set of parameters into the statement.
Multiple calls to ValuesBase.values() will produce a new construct, each one with the parameter list modified to include the new parameters sent. In the typical case of a single dictionary of parameters, the newly passed keys will replace the same keys in the previous construct. In the case of a list-based “multiple values” construct, each new list of values is extended onto the existing list of values.
Parameters: |
|
---|
See also
Inserts and Updates - SQL Expression Language Tutorial
insert() - produce an INSERT statement
update() - produce an UPDATE statement
Add a table hint for a single table to this INSERT/UPDATE/DELETE statement.
Note
UpdateBase.with_hint() currently applies only to Microsoft SQL Server. For MySQL INSERT/UPDATE/DELETE hints, use UpdateBase.prefix_with().
The text of the hint is rendered in the appropriate location for the database backend in use, relative to the Table that is the subject of this statement, or optionally to that of the given Table passed as the selectable argument.
The dialect_name option will limit the rendering of a particular hint to a particular backend. Such as, to add a hint that only takes effect for SQL Server:
mytable.insert().with_hint("WITH (PAGLOCK)", dialect_name="mssql")
New in version 0.7.6.
Parameters: |
|
---|
Bases: sqlalchemy.sql.expression.FromClause
represent a JOIN construct between two FromClause elements.
The public constructor function for Join is the module-level join() function, as well as the join() method available off all FromClause subclasses.
Construct a new Join.
The usual entrypoint here is the join() function or the FromClause.join() method of any FromClause object.
return an alias of this Join.
Used against a Join object, alias() calls the select() method first so that a subquery against a select() construct is generated. the select() construct also has the correlate flag set to False and will not auto-correlate inside an enclosing select() construct.
The equivalent long-hand form, given a Join object j, is:
from sqlalchemy import select, alias
j = alias(
select([j.left, j.right]).\
select_from(j).\
with_labels(True).\
correlate(False),
name=name
)
See alias() for further details on aliases.
An alias for the columns attribute.
A named-based collection of ColumnElement objects maintained by this FromClause.
The columns, or c collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:
select([mytable]).where(mytable.c.somecolumn == 5)
Compare this ClauseElement to the given ClauseElement.
Subclasses should override the default behavior, which is a straight identity comparison.
**kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see ColumnElement)
Compile this SQL expression.
The return value is a Compiled object. Calling str() or unicode() on the returned value will yield a string representation of the result. The Compiled object also can return a dictionary of bind parameter names and values using the params accessor.
Parameters: |
|
---|
Return corresponding_column for the given column, or if None search for a match in the given dictionary.
Given a ColumnElement, return the exported ColumnElement object from this Selectable which corresponds to that original Column via a common ancestor column.
Parameters: |
|
---|
the given ColumnElement, if the given ColumnElement is actually present within a sub-element of this FromClause. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this FromClause.
return a SELECT COUNT generated against this FromClause.
Return the collection of ForeignKey objects which this FromClause references.
return a join of this FromClause against another FromClause.
return an outer join of this FromClause against another FromClause.
Return a copy with bindparam() elements replaced.
Returns a copy of this ClauseElement with bindparam() elements replaced with values taken from the given dictionary:
>>> clause = column('x') + bindparam('foo')
>>> print clause.compile().params
{'foo':None}
>>> print clause.params({'foo':7}).compile().params
{'foo':7}
Return the collection of Column objects which comprise the primary key of this FromClause.
replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this FromClause.
Create a Select from this Join.
The equivalent long-hand form, given a Join object j, is:
from sqlalchemy import select
j = select([j.left, j.right], **kw).\
where(whereclause).\
select_from(j)
Parameters: |
---|
Return a copy with bindparam() elements replaced.
Same functionality as params(), except adds unique=True to affected bind parameters so that multiple statements can be used.
Base of comparison and logical operators.
Implements base methods operate() and reverse_operate(), as well as __and__(), __or__(), __invert__().
Usually is used via its most common subclass ColumnOperators.
Implement the & operator.
When used with SQL expressions, results in an AND operation, equivalent to and_(), that is:
a & b
is equivalent to:
from sqlalchemy import and_
and_(a, b)
Care should be taken when using & regarding operator precedence; the & operator has the highest precedence. The operands should be enclosed in parenthesis if they contain further sub expressions:
(a == 2) & (b == 4)
Implement the ~ operator.
When used with SQL expressions, results in a NOT operation, equivalent to not_(), that is:
~a
is equivalent to:
from sqlalchemy import not_
not_(a)
Implement the | operator.
When used with SQL expressions, results in an OR operation, equivalent to or_(), that is:
a | b
is equivalent to:
from sqlalchemy import or_
or_(a, b)
Care should be taken when using | regarding operator precedence; the | operator has the highest precedence. The operands should be enclosed in parenthesis if they contain further sub expressions:
(a == 2) | (b == 4)
list of weak references to the object (if defined)
produce a generic operator function.
e.g.:
somecolumn.op("*")(5)
produces:
somecolumn * 5
This function can also be used to make bitwise operators explicit. For example:
somecolumn.op('&')(0xff)
is a bitwise AND of the value in somecolumn.
Parameters: |
|
---|
Operate on an argument.
This is the lowest level of operation, raises NotImplementedError by default.
Overriding this on a subclass can allow common behavior to be applied to all operations. For example, overriding ColumnOperators to apply func.lower() to the left and right side:
class MyComparator(ColumnOperators):
def operate(self, op, other):
return op(func.lower(self), func.lower(other))
Parameters: |
|
---|
Reverse operate on an argument.
Usage is the same as operate().
Bases: sqlalchemy.sql.expression.HasPrefixes, sqlalchemy.sql.expression.SelectBase
Represents a SELECT statement.
See also:
Construct a Select object.
The public constructor for Select is the select() function; see that function for argument descriptions.
Additional generative and mutator methods are available on the SelectBase superclass.
return an alias of this FromClause.
This is shorthand for calling:
from sqlalchemy import alias
a = alias(self, name=name)
See alias() for details.
append the given column expression to the columns clause of this select() construct.
append the given correlation expression to this select() construct.
append the given FromClause expression to this select() construct’s FROM clause.
Append the given GROUP BY criterion applied to this selectable.
The criterion will be appended to any pre-existing GROUP BY criterion.
append the given expression to this select() construct’s HAVING criterion.
The expression will be joined to existing HAVING criterion via AND.
Append the given ORDER BY criterion applied to this selectable.
The criterion will be appended to any pre-existing ORDER BY criterion.
append the given columns clause prefix expression to this select() construct.
append the given expression to this select() construct’s WHERE criterion.
The expression will be joined to existing WHERE criterion via AND.
return a new selectable with the ‘use_labels’ flag set to True.
This will result in column expressions being generated using labels against their table name, such as “SELECT somecolumn AS tablename_somecolumn”. This allows selectables which contain multiple FROM clauses to produce a unique set of column names regardless of name conflicts among the individual FROM clauses.
return a ‘scalar’ representation of this selectable, which can be used as a column expression.
Typically, a select statement which has only one column in its columns clause is eligible to be used as a scalar expression.
The returned object is an instance of ScalarSelect.
return a new selectable with the ‘autocommit’ flag set to
Deprecated since version 0.6: autocommit() is deprecated. Use Executable.execution_options() with the ‘autocommit’ flag.
True.
An alias for the columns attribute.
return a new select() construct with the given column expression added to its columns clause.
A named-based collection of ColumnElement objects maintained by this FromClause.
The columns, or c collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:
select([mytable]).where(mytable.c.somecolumn == 5)
Compare this ClauseElement to the given ClauseElement.
Subclasses should override the default behavior, which is a straight identity comparison.
**kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see ColumnElement)
Compile this SQL expression.
The return value is a Compiled object. Calling str() or unicode() on the returned value will yield a string representation of the result. The Compiled object also can return a dictionary of bind parameter names and values using the params accessor.
Parameters: |
|
---|
return a new select() construct which will correlate the given FROM clauses to that of an enclosing select(), if a match is found.
By “match”, the given fromclause must be present in this select’s list of FROM objects and also present in an enclosing select’s list of FROM objects.
Calling this method turns off the select’s default behavior of “auto-correlation”. Normally, select() auto-correlates all of its FROM clauses to those of an embedded select when compiled.
If the fromclause is None, correlation is disabled for the returned select().
“Return a new select() construct which will auto-correlate on FROM clauses of enclosing selectables, except for those FROM clauses specified here.
Return corresponding_column for the given column, or if None search for a match in the given dictionary.
Given a ColumnElement, return the exported ColumnElement object from this Selectable which corresponds to that original Column via a common ancestor column.
Parameters: |
|
---|
the given ColumnElement, if the given ColumnElement is actually present within a sub-element of this FromClause. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this FromClause.
return a SELECT COUNT generated against this FromClause.
Return a new CTE, or Common Table Expression instance.
Common table expressions are a SQL standard whereby SELECT statements can draw upon secondary statements specified along with the primary statement, using a clause called “WITH”. Special semantics regarding UNION can also be employed to allow “recursive” queries, where a SELECT statement can draw upon the set of rows that have previously been selected.
SQLAlchemy detects CTE objects, which are treated similarly to Alias objects, as special elements to be delivered to the FROM clause of the statement as well as to a WITH clause at the top of the statement.
New in version 0.7.6.
Parameters: |
|
---|
The following examples illustrate two examples from Postgresql’s documentation at http://www.postgresql.org/docs/8.4/static/queries-with.html.
Example 1, non recursive:
from sqlalchemy import Table, Column, String, Integer, MetaData, \
select, func
metadata = MetaData()
orders = Table('orders', metadata,
Column('region', String),
Column('amount', Integer),
Column('product', String),
Column('quantity', Integer)
)
regional_sales = select([
orders.c.region,
func.sum(orders.c.amount).label('total_sales')
]).group_by(orders.c.region).cte("regional_sales")
top_regions = select([regional_sales.c.region]).\
where(
regional_sales.c.total_sales >
select([
func.sum(regional_sales.c.total_sales)/10
])
).cte("top_regions")
statement = select([
orders.c.region,
orders.c.product,
func.sum(orders.c.quantity).label("product_units"),
func.sum(orders.c.amount).label("product_sales")
]).where(orders.c.region.in_(
select([top_regions.c.region])
)).group_by(orders.c.region, orders.c.product)
result = conn.execute(statement).fetchall()
Example 2, WITH RECURSIVE:
from sqlalchemy import Table, Column, String, Integer, MetaData, \
select, func
metadata = MetaData()
parts = Table('parts', metadata,
Column('part', String),
Column('sub_part', String),
Column('quantity', Integer),
)
included_parts = select([
parts.c.sub_part,
parts.c.part,
parts.c.quantity]).\
where(parts.c.part=='our part').\
cte(recursive=True)
incl_alias = included_parts.alias()
parts_alias = parts.alias()
included_parts = included_parts.union_all(
select([
parts_alias.c.part,
parts_alias.c.sub_part,
parts_alias.c.quantity
]).
where(parts_alias.c.part==incl_alias.c.sub_part)
)
statement = select([
included_parts.c.sub_part,
func.sum(included_parts.c.quantity).
label('total_quantity')
]). select_from(included_parts.join(parts,
included_parts.c.part==parts.c.part)).\
group_by(included_parts.c.sub_part)
result = conn.execute(statement).fetchall()
See also:
orm.query.Query.cte() - ORM version of SelectBase.cte().
a brief description of this FromClause.
Used primarily for error message formatting.
Return a new select() construct which will apply DISTINCT to its columns clause.
Parameters: | *expr – optional column expressions. When present, the Postgresql dialect will render a DISTINCT ON (<expressions>>) construct. |
---|
return a SQL EXCEPT of this select() construct against the given selectable.
return a SQL EXCEPT ALL of this select() construct against the given selectable.
Compile and execute this Executable.
Set non-SQL options for the statement which take effect during execution.
Execution options can be set on a per-statement or per Connection basis. Additionally, the Engine and ORM Query objects provide access to execution options which they in turn configure upon connections.
The execution_options() method is generative. A new instance of this statement is returned that contains the options:
statement = select([table.c.x, table.c.y])
statement = statement.execution_options(autocommit=True)
Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See Connection.execution_options() for a full list of possible options.
See also:
Return the collection of ForeignKey objects which this FromClause references.
Return the displayed list of FromClause elements.
return child elements as per the ClauseElement specification.
return a new selectable with the given list of GROUP BY criterion applied.
The criterion will be appended to any pre-existing GROUP BY criterion.
return a new select() construct with the given expression added to its HAVING clause, joined to the existing clause via AND, if any.
an iterator of all ColumnElement expressions which would be rendered into the columns clause of the resulting SELECT statement.
return a SQL INTERSECT of this select() construct against the given selectable.
return a SQL INTERSECT ALL of this select() construct against the given selectable.
return a join of this FromClause against another FromClause.
return a ‘scalar’ representation of this selectable, embedded as a subquery with a label.
See also as_scalar().
return a new selectable with the given LIMIT criterion applied.
return a Set of all FromClause elements referenced by this Select.
This set is a superset of that returned by the froms property, which is specifically for those FromClause elements that would actually be rendered.
return a new selectable with the given OFFSET criterion applied.
return a new selectable with the given list of ORDER BY criterion applied.
The criterion will be appended to any pre-existing ORDER BY criterion.
return an outer join of this FromClause against another FromClause.
Return a copy with bindparam() elements replaced.
Returns a copy of this ClauseElement with bindparam() elements replaced with values taken from the given dictionary:
>>> clause = column('x') + bindparam('foo')
>>> print clause.compile().params
{'foo':None}
>>> print clause.params({'foo':7}).compile().params
{'foo':7}
Add one or more expressions following the statement keyword, i.e. SELECT, INSERT, UPDATE, or DELETE. Generative.
This is used to support backend-specific prefix keywords such as those provided by MySQL.
E.g.:
stmt = table.insert().prefix_with("LOW_PRIORITY", dialect="mysql")
Multiple prefixes can be specified by multiple calls to prefix_with().
Parameters: |
|
---|
Return the collection of Column objects which comprise the primary key of this FromClause.
Return a new :func`.select` construct with redundantly named, equivalently-valued columns removed from the columns clause.
“Redundant” here means two columns where one refers to the other either based on foreign key, or via a simple equality comparison in the WHERE clause of the statement. The primary purpose of this method is to automatically construct a select statement with all uniquely-named columns, without the need to use table-qualified labels as apply_labels() does.
When columns are omitted based on foreign key, the referred-to column is the one that’s kept. When columns are omitted based on WHERE eqivalence, the first column in the columns clause is the one that’s kept.
Parameters: | only_synonyms – when True, limit the removal of columns to those which have the same name as the equivalent. Otherwise, all columns that are equivalent to another are removed. |
---|
New in version 0.8.
replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this FromClause.
Compile and execute this Executable, returning the result’s scalar representation.
return a SELECT of this FromClause.
return a new select() construct with the given FROM expression merged into its list of FROM objects.
E.g.:
table1 = table('t1', column('a'))
table2 = table('t2', column('b'))
s = select([table1.c.a]).\
select_from(
table1.join(table2, table1.c.a==table2.c.b)
)
The “from” list is a unique set on the identity of each element, so adding an already present Table or other selectable will have no effect. Passing a Join that refers to an already present Table or other selectable will have the effect of concealing the presence of that selectable as an individual element in the rendered FROM list, instead rendering it into a JOIN clause.
While the typical purpose of Select.select_from() is to replace the default, derived FROM clause with a join, it can also be called with individual table elements, multiple times if desired, in the case that the FROM clause cannot be fully derived from the columns clause:
select([func.count('*')]).select_from(table1)
return a ‘grouping’ construct as per the ClauseElement specification.
This produces an element that can be embedded in an expression. Note that this method is called automatically as needed when constructing expressions and should not require explicit use.
return a SQL UNION of this select() construct against the given selectable.
return a SQL UNION ALL of this select() construct against the given selectable.
Return a copy with bindparam() elements replaced.
Same functionality as params(), except adds unique=True to affected bind parameters so that multiple statements can be used.
return a new select() construct with the given expression added to its WHERE clause, joined to the existing clause via AND, if any.
Add an indexing hint for the given selectable to this Select.
The text of the hint is rendered in the appropriate location for the database backend in use, relative to the given Table or Alias passed as the selectable argument. The dialect implementation typically uses Python string substitution syntax with the token %(name)s to render the name of the table or alias. E.g. when using Oracle, the following:
select([mytable]).\
with_hint(mytable, "+ index(%(name)s ix_mytable)")
Would render SQL as:
select /*+ index(mytable ix_mytable) */ ... from mytable
The dialect_name option will limit the rendering of a particular hint to a particular backend. Such as, to add hints for both Oracle and Sybase simultaneously:
select([mytable]).\
with_hint(mytable, "+ index(%(name)s ix_mytable)", 'oracle').\
with_hint(mytable, "WITH INDEX ix_mytable", 'sybase')
Return a new select() construct with its columns clause replaced with the given columns.
Changed in version 0.7.3: Due to a bug fix, this method has a slight behavioral change as of version 0.7.3. Prior to version 0.7.3, the FROM clause of a select() was calculated upfront and as new columns were added; in 0.7.3 and later it’s calculated at compile time, fixing an issue regarding late binding of columns to parent tables. This changes the behavior of Select.with_only_columns() in that FROM clauses no longer represented in the new list are dropped, but this behavior is more consistent in that the FROM clauses are consistently derived from the current columns clause. The original intent of this method is to allow trimming of the existing columns list to be fewer columns than originally present; the use case of replacing the columns list with an entirely different one hadn’t been anticipated until 0.7.3 was released; the usage guidelines below illustrate how this should be done.
This method is exactly equivalent to as if the original select() had been called with the given columns clause. I.e. a statement:
s = select([table1.c.a, table1.c.b])
s = s.with_only_columns([table1.c.b])
should be exactly equivalent to:
s = select([table1.c.b])
This means that FROM clauses which are only derived from the column list will be discarded if the new column list no longer contains that FROM:
>>> table1 = table('t1', column('a'), column('b'))
>>> table2 = table('t2', column('a'), column('b'))
>>> s1 = select([table1.c.a, table2.c.b])
>>> print s1
SELECT t1.a, t2.b FROM t1, t2
>>> s2 = s1.with_only_columns([table2.c.b])
>>> print s2
SELECT t2.b FROM t1
The preferred way to maintain a specific FROM clause in the construct, assuming it won’t be represented anywhere else (i.e. not in the WHERE clause, etc.) is to set it using Select.select_from():
>>> s1 = select([table1.c.a, table2.c.b]).\
... select_from(table1.join(table2,
... table1.c.a==table2.c.a))
>>> s2 = s1.with_only_columns([table2.c.b])
>>> print s2
SELECT t2.b FROM t1 JOIN t2 ON t1.a=t2.a
Care should also be taken to use the correct set of column objects passed to Select.with_only_columns(). Since the method is essentially equivalent to calling the select() construct in the first place with the given columns, the columns passed to Select.with_only_columns() should usually be a subset of those which were passed to the select() construct, not those which are available from the .c collection of that select(). That is:
s = select([table1.c.a, table1.c.b]).select_from(table1)
s = s.with_only_columns([table1.c.b])
and not:
# usually incorrect
s = s.with_only_columns([s.c.b])
The latter would produce the SQL:
SELECT b
FROM (SELECT t1.a AS a, t1.b AS b
FROM t1), t1
Since the select() construct is essentially being asked to select both from table1 as well as itself.
Bases: sqlalchemy.sql.expression.ClauseElement
mark a class as being selectable
Bases: sqlalchemy.sql.expression.Executable, sqlalchemy.sql.expression.FromClause
Base class for Select and CompoundSelects.
Append the given GROUP BY criterion applied to this selectable.
The criterion will be appended to any pre-existing GROUP BY criterion.
Append the given ORDER BY criterion applied to this selectable.
The criterion will be appended to any pre-existing ORDER BY criterion.
return a new selectable with the ‘use_labels’ flag set to True.
This will result in column expressions being generated using labels against their table name, such as “SELECT somecolumn AS tablename_somecolumn”. This allows selectables which contain multiple FROM clauses to produce a unique set of column names regardless of name conflicts among the individual FROM clauses.
return a ‘scalar’ representation of this selectable, which can be used as a column expression.
Typically, a select statement which has only one column in its columns clause is eligible to be used as a scalar expression.
The returned object is an instance of ScalarSelect.
return a new selectable with the ‘autocommit’ flag set to
Deprecated since version 0.6: autocommit() is deprecated. Use Executable.execution_options() with the ‘autocommit’ flag.
True.
Return a new CTE, or Common Table Expression instance.
Common table expressions are a SQL standard whereby SELECT statements can draw upon secondary statements specified along with the primary statement, using a clause called “WITH”. Special semantics regarding UNION can also be employed to allow “recursive” queries, where a SELECT statement can draw upon the set of rows that have previously been selected.
SQLAlchemy detects CTE objects, which are treated similarly to Alias objects, as special elements to be delivered to the FROM clause of the statement as well as to a WITH clause at the top of the statement.
New in version 0.7.6.
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The following examples illustrate two examples from Postgresql’s documentation at http://www.postgresql.org/docs/8.4/static/queries-with.html.
Example 1, non recursive:
from sqlalchemy import Table, Column, String, Integer, MetaData, \
select, func
metadata = MetaData()
orders = Table('orders', metadata,
Column('region', String),
Column('amount', Integer),
Column('product', String),
Column('quantity', Integer)
)
regional_sales = select([
orders.c.region,
func.sum(orders.c.amount).label('total_sales')
]).group_by(orders.c.region).cte("regional_sales")
top_regions = select([regional_sales.c.region]).\
where(
regional_sales.c.total_sales >
select([
func.sum(regional_sales.c.total_sales)/10
])
).cte("top_regions")
statement = select([
orders.c.region,
orders.c.product,
func.sum(orders.c.quantity).label("product_units"),
func.sum(orders.c.amount).label("product_sales")
]).where(orders.c.region.in_(
select([top_regions.c.region])
)).group_by(orders.c.region, orders.c.product)
result = conn.execute(statement).fetchall()
Example 2, WITH RECURSIVE:
from sqlalchemy import Table, Column, String, Integer, MetaData, \
select, func
metadata = MetaData()
parts = Table('parts', metadata,
Column('part', String),
Column('sub_part', String),
Column('quantity', Integer),
)
included_parts = select([
parts.c.sub_part,
parts.c.part,
parts.c.quantity]).\
where(parts.c.part=='our part').\
cte(recursive=True)
incl_alias = included_parts.alias()
parts_alias = parts.alias()
included_parts = included_parts.union_all(
select([
parts_alias.c.part,
parts_alias.c.sub_part,
parts_alias.c.quantity
]).
where(parts_alias.c.part==incl_alias.c.sub_part)
)
statement = select([
included_parts.c.sub_part,
func.sum(included_parts.c.quantity).
label('total_quantity')
]). select_from(included_parts.join(parts,
included_parts.c.part==parts.c.part)).\
group_by(included_parts.c.sub_part)
result = conn.execute(statement).fetchall()
See also:
orm.query.Query.cte() - ORM version of SelectBase.cte().
return a new selectable with the given list of GROUP BY criterion applied.
The criterion will be appended to any pre-existing GROUP BY criterion.
return a ‘scalar’ representation of this selectable, embedded as a subquery with a label.
See also as_scalar().
return a new selectable with the given LIMIT criterion applied.
return a new selectable with the given OFFSET criterion applied.
return a new selectable with the given list of ORDER BY criterion applied.
The criterion will be appended to any pre-existing ORDER BY criterion.
Bases: sqlalchemy.sql.expression.Immutable, sqlalchemy.sql.expression.FromClause
Represents a minimal “table” construct.
The constructor for TableClause is the table() function. This produces a lightweight table object that has only a name and a collection of columns, which are typically produced by the column() function:
from sqlalchemy.sql import table, column
user = table("user",
column("id"),
column("name"),
column("description"),
)
The TableClause construct serves as the base for the more commonly used Table object, providing the usual set of FromClause services including the .c. collection and statement generation methods.
It does not provide all the additional schema-level services of Table, including constraints, references to other tables, or support for MetaData-level services. It’s useful on its own as an ad-hoc construct used to generate quick SQL statements when a more fully fledged Table is not on hand.
return an alias of this FromClause.
This is shorthand for calling:
from sqlalchemy import alias
a = alias(self, name=name)
See alias() for details.
An alias for the columns attribute.
A named-based collection of ColumnElement objects maintained by this FromClause.
The columns, or c collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:
select([mytable]).where(mytable.c.somecolumn == 5)
Compare this ClauseElement to the given ClauseElement.
Subclasses should override the default behavior, which is a straight identity comparison.
**kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see ColumnElement)
Compile this SQL expression.
The return value is a Compiled object. Calling str() or unicode() on the returned value will yield a string representation of the result. The Compiled object also can return a dictionary of bind parameter names and values using the params accessor.
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Return corresponding_column for the given column, or if None search for a match in the given dictionary.
Given a ColumnElement, return the exported ColumnElement object from this Selectable which corresponds to that original Column via a common ancestor column.
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the given ColumnElement, if the given ColumnElement is actually present within a sub-element of this FromClause. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this FromClause.
return a SELECT COUNT generated against this TableClause.
Generate a delete() construct against this TableClause.
E.g.:
table.delete().where(table.c.id==7)
See delete() for argument and usage information.
Return the collection of ForeignKey objects which this FromClause references.
TableClause doesn’t support having a primary key or column -level defaults, so implicit returning doesn’t apply.
Generate an insert() construct against this TableClause.
E.g.:
table.insert().values(name='foo')
See insert() for argument and usage information.
Return True if this FromClause is ‘derived’ from the given FromClause.
An example would be an Alias of a Table is derived from that Table.
return a join of this FromClause against another FromClause.
return an outer join of this FromClause against another FromClause.
Return the collection of Column objects which comprise the primary key of this FromClause.
replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this FromClause.
return a SELECT of this FromClause.
Apply a ‘grouping’ to this ClauseElement.
This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by select() constructs when placed into the FROM clause of another select(). (Note that subqueries should be normally created using the Select.alias() method, as many platforms require nested SELECT statements to be named).
As expressions are composed together, the application of self_group() is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like x OR (y AND z) - AND takes precedence over OR.
The base self_group() method of ClauseElement just returns self.
Generate an update() construct against this TableClause.
E.g.:
table.update().where(table.c.id==7).values(name='foo')
See update() for argument and usage information.
Bases: sqlalchemy.sql.expression.ColumnElement
Define a ‘unary’ expression.
A unary expression has a single column expression and an operator. The operator can be placed on the left (where it is called the ‘operator’) or right (where it is called the ‘modifier’) of the column expression.
Compare this UnaryExpression against the given ClauseElement.
Bases: sqlalchemy.sql.expression.ValuesBase
Represent an Update construct.
The Update object is created using the update() function.
Return a ‘bind’ linked to this UpdateBase or a Table associated with it.
Compare this ClauseElement to the given ClauseElement.
Subclasses should override the default behavior, which is a straight identity comparison.
**kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see ColumnElement)
Compile this SQL expression.
The return value is a Compiled object. Calling str() or unicode() on the returned value will yield a string representation of the result. The Compiled object also can return a dictionary of bind parameter names and values using the params accessor.
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Compile and execute this Executable.
Set non-SQL options for the statement which take effect during execution.
Execution options can be set on a per-statement or per Connection basis. Additionally, the Engine and ORM Query objects provide access to execution options which they in turn configure upon connections.
The execution_options() method is generative. A new instance of this statement is returned that contains the options:
statement = select([table.c.x, table.c.y])
statement = statement.execution_options(autocommit=True)
Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See Connection.execution_options() for a full list of possible options.
See also:
Set the parameters for the statement.
This method raises NotImplementedError on the base class, and is overridden by ValuesBase to provide the SET/VALUES clause of UPDATE and INSERT.
Add one or more expressions following the statement keyword, i.e. SELECT, INSERT, UPDATE, or DELETE. Generative.
This is used to support backend-specific prefix keywords such as those provided by MySQL.
E.g.:
stmt = table.insert().prefix_with("LOW_PRIORITY", dialect="mysql")
Multiple prefixes can be specified by multiple calls to prefix_with().
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Add a RETURNING or equivalent clause to this statement.
The given list of columns represent columns within the table that is the target of the INSERT, UPDATE, or DELETE. Each element can be any column expression. Table objects will be expanded into their individual columns.
Upon compilation, a RETURNING clause, or database equivalent, will be rendered within the statement. For INSERT and UPDATE, the values are the newly inserted/updated values. For DELETE, the values are those of the rows which were deleted.
Upon execution, the values of the columns to be returned are made available via the result set and can be iterated using fetchone() and similar. For DBAPIs which do not natively support returning values (i.e. cx_oracle), SQLAlchemy will approximate this behavior at the result level so that a reasonable amount of behavioral neutrality is provided.
Note that not all databases/DBAPIs support RETURNING. For those backends with no support, an exception is raised upon compilation and/or execution. For those who do support it, the functionality across backends varies greatly, including restrictions on executemany() and other statements which return multiple rows. Please read the documentation notes for the database in use in order to determine the availability of RETURNING.
Compile and execute this Executable, returning the result’s scalar representation.
Apply a ‘grouping’ to this ClauseElement.
This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by select() constructs when placed into the FROM clause of another select(). (Note that subqueries should be normally created using the Select.alias() method, as many platforms require nested SELECT statements to be named).
As expressions are composed together, the application of self_group() is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like x OR (y AND z) - AND takes precedence over OR.
The base self_group() method of ClauseElement just returns self.
Return a copy with bindparam() elements replaced.
Same functionality as params(), except adds unique=True to affected bind parameters so that multiple statements can be used.
specify a fixed VALUES clause for an INSERT statement, or the SET clause for an UPDATE.
Note that the Insert and Update constructs support per-execution time formatting of the VALUES and/or SET clauses, based on the arguments passed to Connection.execute(). However, the ValuesBase.values() method can be used to “fix” a particular set of parameters into the statement.
Multiple calls to ValuesBase.values() will produce a new construct, each one with the parameter list modified to include the new parameters sent. In the typical case of a single dictionary of parameters, the newly passed keys will replace the same keys in the previous construct. In the case of a list-based “multiple values” construct, each new list of values is extended onto the existing list of values.
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See also
Inserts and Updates - SQL Expression Language Tutorial
insert() - produce an INSERT statement
update() - produce an UPDATE statement
return a new update() construct with the given expression added to its WHERE clause, joined to the existing clause via AND, if any.
Add a table hint for a single table to this INSERT/UPDATE/DELETE statement.
Note
UpdateBase.with_hint() currently applies only to Microsoft SQL Server. For MySQL INSERT/UPDATE/DELETE hints, use UpdateBase.prefix_with().
The text of the hint is rendered in the appropriate location for the database backend in use, relative to the Table that is the subject of this statement, or optionally to that of the given Table passed as the selectable argument.
The dialect_name option will limit the rendering of a particular hint to a particular backend. Such as, to add a hint that only takes effect for SQL Server:
mytable.insert().with_hint("WITH (PAGLOCK)", dialect_name="mssql")
New in version 0.7.6.
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Bases: sqlalchemy.sql.expression.HasPrefixes, sqlalchemy.sql.expression.Executable, sqlalchemy.sql.expression.ClauseElement
Form the base for INSERT, UPDATE, and DELETE statements.
Return a ‘bind’ linked to this UpdateBase or a Table associated with it.
Set the parameters for the statement.
This method raises NotImplementedError on the base class, and is overridden by ValuesBase to provide the SET/VALUES clause of UPDATE and INSERT.
Add a RETURNING or equivalent clause to this statement.
The given list of columns represent columns within the table that is the target of the INSERT, UPDATE, or DELETE. Each element can be any column expression. Table objects will be expanded into their individual columns.
Upon compilation, a RETURNING clause, or database equivalent, will be rendered within the statement. For INSERT and UPDATE, the values are the newly inserted/updated values. For DELETE, the values are those of the rows which were deleted.
Upon execution, the values of the columns to be returned are made available via the result set and can be iterated using fetchone() and similar. For DBAPIs which do not natively support returning values (i.e. cx_oracle), SQLAlchemy will approximate this behavior at the result level so that a reasonable amount of behavioral neutrality is provided.
Note that not all databases/DBAPIs support RETURNING. For those backends with no support, an exception is raised upon compilation and/or execution. For those who do support it, the functionality across backends varies greatly, including restrictions on executemany() and other statements which return multiple rows. Please read the documentation notes for the database in use in order to determine the availability of RETURNING.
Add a table hint for a single table to this INSERT/UPDATE/DELETE statement.
Note
UpdateBase.with_hint() currently applies only to Microsoft SQL Server. For MySQL INSERT/UPDATE/DELETE hints, use UpdateBase.prefix_with().
The text of the hint is rendered in the appropriate location for the database backend in use, relative to the Table that is the subject of this statement, or optionally to that of the given Table passed as the selectable argument.
The dialect_name option will limit the rendering of a particular hint to a particular backend. Such as, to add a hint that only takes effect for SQL Server:
mytable.insert().with_hint("WITH (PAGLOCK)", dialect_name="mssql")
New in version 0.7.6.
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Bases: sqlalchemy.sql.expression.UpdateBase
Supplies support for ValuesBase.values() to INSERT and UPDATE constructs.
specify a fixed VALUES clause for an INSERT statement, or the SET clause for an UPDATE.
Note that the Insert and Update constructs support per-execution time formatting of the VALUES and/or SET clauses, based on the arguments passed to Connection.execute(). However, the ValuesBase.values() method can be used to “fix” a particular set of parameters into the statement.
Multiple calls to ValuesBase.values() will produce a new construct, each one with the parameter list modified to include the new parameters sent. In the typical case of a single dictionary of parameters, the newly passed keys will replace the same keys in the previous construct. In the case of a list-based “multiple values” construct, each new list of values is extended onto the existing list of values.
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See also
Inserts and Updates - SQL Expression Language Tutorial
insert() - produce an INSERT statement
update() - produce an UPDATE statement
SQL functions which are known to SQLAlchemy with regards to database-specific rendering, return types and argument behavior. Generic functions are invoked like all SQL functions, using the func attribute:
select([func.count()]).select_from(sometable)
Note that any name not known to func generates the function name as is - there is no restriction on what SQL functions can be called, known or unknown to SQLAlchemy, built-in or user defined. The section here only describes those functions where SQLAlchemy already knows what argument and return types are in use.
Bases: sqlalchemy.sql.functions.GenericFunction
Bases: sqlalchemy.sql.expression.Function
Define a ‘generic’ function.
A generic function is a pre-established Function class that is instantiated automatically when called by name from the func attribute. Note that calling any name from func has the effect that a new Function instance is created automatically, given that name. The primary use case for defining a GenericFunction class is so that a function of a particular name may be given a fixed return type. It can also include custom argument parsing schemes as well as additional methods.
Subclasses of GenericFunction are automatically registered under the name of the class. For example, a user-defined function as_utc() would be available immediately:
from sqlalchemy.sql.functions import GenericFunction
from sqlalchemy.types import DateTime
class as_utc(GenericFunction):
type = DateTime
print select([func.as_utc()])
User-defined generic functions can be organized into packages by specifying the “package” attribute when defining GenericFunction. Third party libraries containing many functions may want to use this in order to avoid name conflicts with other systems. For example, if our as_utc() function were part of a package “time”:
class as_utc(GenericFunction):
type = DateTime
package = "time"
The above function would be available from func using the package name time:
print select([func.time.as_utc()])
A final option is to allow the function to be accessed from one name in func but to render as a different name. The identifier attribute will override the name used to access the function as loaded from func, but will retain the usage of name as the rendered name:
class GeoBuffer(GenericFunction):
type = Geometry
package = "geo"
name = "ST_Buffer"
identifier = "buffer"
The above function will render as follows:
>>> print func.geo.buffer()
ST_Buffer()
New in version 0.8: GenericFunction now supports automatic registration of new functions as well as package and custom naming support.
Changed in version 0.8: The attribute name type is used to specify the function’s return type at the class level. Previously, the name __return_type__ was used. This name is still recognized for backwards-compatibility.
Bases: sqlalchemy.sql.functions.GenericFunction
Define a function whose return type is the same as its arguments.
Bases: sqlalchemy.sql.functions.GenericFunction
alias of Integer
Bases: sqlalchemy.sql.functions.ReturnTypeFromArgs
Bases: sqlalchemy.sql.functions.GenericFunction
alias of String
Bases: sqlalchemy.sql.functions.GenericFunction
The ANSI COUNT aggregate function. With no arguments, emits COUNT *.
alias of Integer
Bases: sqlalchemy.sql.functions.AnsiFunction
alias of Date
Bases: sqlalchemy.sql.functions.AnsiFunction
alias of Time
Bases: sqlalchemy.sql.functions.AnsiFunction
alias of DateTime
Bases: sqlalchemy.sql.functions.AnsiFunction
alias of String
Bases: sqlalchemy.sql.functions.AnsiFunction
alias of DateTime
Bases: sqlalchemy.sql.functions.AnsiFunction
alias of DateTime
Bases: sqlalchemy.sql.functions.ReturnTypeFromArgs
Bases: sqlalchemy.sql.functions.ReturnTypeFromArgs
Bases: sqlalchemy.sql.functions.GenericFunction
Represent the ‘next value’, given a Sequence as it’s single argument.
Compiles into the appropriate function on each backend, or will raise NotImplementedError if used on a backend that does not provide support for sequences.
Bases: sqlalchemy.sql.functions.GenericFunction
alias of DateTime
Bases: sqlalchemy.sql.functions.GenericFunction
Associate a callable with a particular func. name.
This is normally called by _GenericMeta, but is also available by itself so that a non-Function construct can be associated with the func accessor (i.e. CAST, EXTRACT).
Bases: sqlalchemy.sql.functions.AnsiFunction
alias of String
Bases: sqlalchemy.sql.functions.ReturnTypeFromArgs
Bases: sqlalchemy.sql.functions.AnsiFunction
alias of DateTime
Bases: sqlalchemy.sql.functions.AnsiFunction
alias of String