Package Gnumed :: Package pycommon :: Module gmBusinessDBObject
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Source Code for Module Gnumed.pycommon.gmBusinessDBObject

  1  __doc__ = """GNUmed database object business class. 
  2   
  3  Overview 
  4  -------- 
  5  This class wraps a source relation (table, view) which 
  6  represents an entity that makes immediate business sense 
  7  such as a vaccination or a medical document. In many if 
  8  not most cases this source relation is a denormalizing 
  9  view. The data in that view will in most cases, however, 
 10  originate from several normalized tables. One instance 
 11  of this class represents one row of said source relation. 
 12   
 13  Note, however, that this class does not *always* simply 
 14  wrap a single table or view. It can also encompass several 
 15  relations (views, tables, sequences etc) that taken together 
 16  form an object meaningful to *business* logic. 
 17   
 18  Initialization 
 19  -------------- 
 20  There are two ways to initialize an instance with values. 
 21  One way is to pass a "primary key equivalent" object into 
 22  __init__(). Refetch_payload() will then pull the data from 
 23  the backend. Another way would be to fetch the data outside 
 24  the instance and pass it in via the <row> argument. In that 
 25  case the instance will not initially connect to the databse 
 26  which may offer a great boost to performance. 
 27   
 28  Values API 
 29  ---------- 
 30  Field values are cached for later access. They can be accessed 
 31  by a dictionary API, eg: 
 32   
 33          old_value = object['field'] 
 34          object['field'] = new_value 
 35   
 36  The field names correspond to the respective column names 
 37  in the "main" source relation. Accessing non-existant field 
 38  names will raise an error, so does trying to set fields not 
 39  listed in self.__class__._updatable_fields. To actually 
 40  store updated values in the database one must explicitly 
 41  call save_payload(). 
 42   
 43  The class will in many cases be enhanced by accessors to 
 44  related data that is not directly part of the business 
 45  object itself but are closely related, such as codes 
 46  linked to a clinical narrative entry (eg a diagnosis). Such 
 47  accessors in most cases start with get_*. Related setters 
 48  start with set_*. The values can be accessed via the 
 49  object['field'] syntax, too, but they will be cached 
 50  independantly. 
 51   
 52  Concurrency handling 
 53  -------------------- 
 54  GNUmed connections always run transactions in isolation level 
 55  "serializable". This prevents transactions happening at the 
 56  *very same time* to overwrite each other's data. All but one 
 57  of them will abort with a concurrency error (eg if a 
 58  transaction runs a select-for-update later than another one 
 59  it will hang until the first transaction ends. Then it will 
 60  succeed or fail depending on what the first transaction 
 61  did). This is standard transactional behaviour. 
 62   
 63  However, another transaction may have updated our row 
 64  between the time we first fetched the data and the time we 
 65  start the update transaction. This is noticed by getting the 
 66  XMIN system column for the row when initially fetching the 
 67  data and using that value as a where condition value when 
 68  updating the row later. If the row had been updated (xmin 
 69  changed) or deleted (primary key disappeared) in the 
 70  meantime the update will touch zero rows (as no row with 
 71  both PK and XMIN matching is found) even if the query itself 
 72  syntactically succeeds. 
 73   
 74  When detecting a change in a row due to XMIN being different 
 75  one needs to be careful how to represent that to the user. 
 76  The row may simply have changed but it also might have been 
 77  deleted and a completely new and unrelated row which happens 
 78  to have the same primary key might have been created ! This 
 79  row might relate to a totally different context (eg. patient, 
 80  episode, encounter). 
 81   
 82  One can offer all the data to the user: 
 83   
 84  self.payload_most_recently_fetched 
 85  - contains the data at the last successful refetch 
 86   
 87  self.payload_most_recently_attempted_to_store 
 88  - contains the modified payload just before the last 
 89    failure of save_payload() - IOW what is currently 
 90    in the database 
 91   
 92  self._payload 
 93  - contains the currently active payload which may or 
 94    may not contain changes 
 95   
 96  For discussion on this see the thread starting at: 
 97   
 98          http://archives.postgresql.org/pgsql-general/2004-10/msg01352.php 
 99   
100  and here 
101   
102          http://groups.google.com/group/pgsql.general/browse_thread/thread/e3566ba76173d0bf/6cf3c243a86d9233 
103          (google for "XMIN semantic at peril") 
104   
105  Problem cases with XMIN: 
106   
107  1) not unlikely 
108  - a very old row is read with XMIN 
109  - vacuum comes along and sets XMIN to FrozenTransactionId 
110    - now XMIN changed but the row actually didn't ! 
111  - an update with "... where xmin = old_xmin ..." fails 
112    although there is no need to fail 
113   
114  2) quite unlikely 
115  - a row is read with XMIN 
116  - a long time passes 
117  - the original XMIN gets frozen to FrozenTransactionId 
118  - another writer comes along and changes the row 
119  - incidentally the exact same old row gets the old XMIN *again* 
120    - now XMIN is (again) the same but the data changed ! 
121  - a later update fails to detect the concurrent change !! 
122   
123  TODO: 
124  The solution is to use our own column for optimistic locking 
125  which gets updated by an AFTER UPDATE trigger. 
126  """ 
127  #============================================================ 
128  __author__ = "K.Hilbert <Karsten.Hilbert@gmx.net>" 
129  __license__ = "GPL v2 or later" 
130   
131   
132  import sys 
133  import inspect 
134  import logging 
135  import datetime 
136   
137   
138  if __name__ == '__main__': 
139          sys.path.insert(0, '../../') 
140  from Gnumed.pycommon import gmExceptions 
141  from Gnumed.pycommon import gmPG2 
142  from Gnumed.pycommon.gmDateTime import pydt_strftime 
143  from Gnumed.pycommon.gmTools import tex_escape_string 
144  from Gnumed.pycommon.gmTools import xetex_escape_string 
145  from Gnumed.pycommon.gmTools import compare_dict_likes 
146  from Gnumed.pycommon.gmTools import format_dict_like 
147  from Gnumed.pycommon.gmTools import dicts2table 
148  from Gnumed.pycommon.gmTools import u_left_arrow 
149   
150   
151  _log = logging.getLogger('gm.db') 
152   
153  #============================================================ 
154 -class cBusinessDBObject(object):
155 """Represents business objects in the database. 156 157 Rules: 158 - instances ARE ASSUMED TO EXIST in the database 159 - PK construction (aPK_obj): DOES verify its existence on instantiation 160 (fetching data fails) 161 - Row construction (row): allowed by using a dict of pairs 162 field name: field value (PERFORMANCE improvement) 163 - does NOT verify FK target existence 164 - does NOT create new entries in the database 165 - does NOT lazy-fetch fields on access 166 167 Class scope SQL commands and variables: 168 169 <_cmd_fetch_payload> 170 - must return exactly one row 171 - WHERE clause argument values are expected in 172 self.pk_obj (taken from __init__(aPK_obj)) 173 - must return xmin of all rows that _cmds_store_payload 174 will be updating, so views must support the xmin columns 175 of their underlying tables 176 177 <_cmds_store_payload> 178 - one or multiple "update ... set ... where xmin_* = ... and pk* = ..." 179 statements which actually update the database from the data in self._payload, 180 - the last query must refetch at least the XMIN values needed to detect 181 concurrent updates, their field names had better be the same as 182 in _cmd_fetch_payload, 183 - the last query CAN return other fields which is particularly 184 useful when those other fields are computed in the backend 185 and may thus change upon save but will not have been set by 186 the client code explicitely - this is only really of concern 187 if the saved subclass is to be reused after saving rather 188 than re-instantiated 189 - when subclasses tend to live a while after save_payload() was 190 called and they support computed fields (say, _(some_column) 191 you need to return *all* columns (see cEncounter) 192 193 <_updatable_fields> 194 - a list of fields available for update via object['field'] 195 196 197 A template for new child classes: 198 199 *********** start of template *********** 200 201 #------------------------------------------------------------ 202 from Gnumed.pycommon import gmBusinessDBObject 203 from Gnumed.pycommon import gmPG2 204 205 #============================================================ 206 # short description 207 #------------------------------------------------------------ 208 # search/replace "" " -> 3 "s 209 # 210 # search-replace get_XXX, use plural form 211 _SQL_get_XXX = u"" " 212 SELECT *, (xmin AS xmin_XXX) 213 FROM XXX.v_XXX 214 WHERE %s 215 "" " 216 217 class cXxxXxx(gmBusinessDBObject.cBusinessDBObject): 218 "" "Represents ..."" " 219 220 _cmd_fetch_payload = _SQL_get_XXX % u"pk_XXX = %s" 221 _cmds_store_payload = [ 222 u"" " 223 -- typically the underlying table name 224 UPDATE xxx.xxx SET 225 -- typically "table_col = %(view_col)s" 226 xxx = %(xxx)s, 227 xxx = gm.nullify_empty_string(%(xxx)s) 228 WHERE 229 pk = %(pk_XXX)s 230 AND 231 xmin = %(xmin_XXX)s 232 RETURNING 233 xmin AS xmin_XXX 234 -- also return columns which are calculated in the view used by 235 -- the initial SELECT such that they will further on contain their 236 -- updated value: 237 --, ... 238 --, ... 239 "" " 240 ] 241 # view columns that can be updated: 242 _updatable_fields = [ 243 u'xxx', 244 u'xxx' 245 ] 246 #-------------------------------------------------------- 247 # def format(self): 248 # return u'%s' % self 249 250 #------------------------------------------------------------ 251 def get_XXX(order_by=None): 252 if order_by is None: 253 order_by = u'true' 254 else: 255 order_by = u'true ORDER BY %s' % order_by 256 257 cmd = _SQL_get_XXX % order_by 258 rows, idx = gmPG2.run_ro_queries(queries = [{'cmd': cmd}], get_col_idx = True) 259 return [ cXxxXxx(row = {'data': r, 'idx': idx, 'pk_field': 'pk_XXX'}) for r in rows ] 260 #------------------------------------------------------------ 261 def create_xxx(xxx=None, xxx=None): 262 263 args = { 264 u'xxx': xxx, 265 u'xxx': xxx 266 } 267 cmd = u"" " 268 INSERT INTO xxx.xxx ( 269 xxx, 270 xxx, 271 xxx 272 ) VALUES ( 273 %(xxx)s, 274 %(xxx)s, 275 gm.nullify_empty_string(%(xxx)s) 276 ) 277 RETURNING pk 278 --RETURNING * 279 "" " 280 rows, idx = gmPG2.run_rw_queries(queries = [{'cmd': cmd, 'args': args}], return_data = True, get_col_idx = False) 281 #rows, idx = gmPG2.run_rw_queries(queries = [{'cmd': cmd, 'args': args}], return_data = True, get_col_idx = True) 282 283 return cXxxXxx(aPK_obj = rows[0]['pk']) 284 #return cXxxXxx(row = {'data': r, 'idx': idx, 'pk_field': 'pk_XXX'}) 285 286 #------------------------------------------------------------ 287 def delete_xxx(pk_XXX=None): 288 args = {'pk': pk_XXX} 289 cmd = u"DELETE FROM xxx.xxx WHERE pk = %(pk)s" 290 gmPG2.run_rw_queries(queries = [{'cmd': cmd, 'args': args}]) 291 return True 292 #------------------------------------------------------------ 293 294 #------------------------------------------------------------ 295 # widget code 296 #------------------------------------------------------------ 297 def edit_xxx(parent=None, xxx=None, single_entry=False, presets=None): 298 299 #------------------------------------------------------------ 300 def delete_xxx() 301 302 #------------------------------------------------------------ 303 def manage_xxx() 304 305 #------------------------------------------------------------ 306 # remember to add in clinical item generic workflows 307 308 309 *********** end of template *********** 310 311 """ 312 #--------------------------------------------------------
313 - def __init__(self, aPK_obj=None, row=None, link_obj=None):
314 """Init business object. 315 316 Call from child classes: 317 318 super(cChildClass, self).__init__(aPK_obj = aPK_obj, row = row, link_obj = link_obj) 319 """ 320 # initialize those "too early" because checking descendants might 321 # fail which will then call __str__ in stack trace logging if --debug 322 # was given which in turn needs those instance variables 323 self.pk_obj = '<uninitialized>' 324 self._idx = {} 325 self._payload = [] # the cache for backend object values (mainly table fields) 326 self._ext_cache = {} # the cache for extended method's results 327 self._is_modified = False 328 329 # check descendants 330 self.__class__._cmd_fetch_payload 331 self.__class__._cmds_store_payload 332 self.__class__._updatable_fields 333 334 if aPK_obj is not None: 335 self.__init_from_pk(aPK_obj = aPK_obj, link_obj = link_obj) 336 else: 337 self._init_from_row_data(row = row) 338 339 self._is_modified = False
340 341 #--------------------------------------------------------
342 - def __init_from_pk(self, aPK_obj=None, link_obj=None):
343 """Creates a new clinical item instance by its PK. 344 345 aPK_obj can be: 346 - a simple value 347 * the primary key WHERE condition must be 348 a simple column 349 - a dictionary of values 350 * the primary key where condition must be a 351 subselect consuming the dict and producing 352 the single-value primary key 353 """ 354 self.pk_obj = aPK_obj 355 result = self.refetch_payload(link_obj = link_obj) 356 if result is True: 357 self.payload_most_recently_fetched = {} 358 for field in self._idx.keys(): 359 self.payload_most_recently_fetched[field] = self._payload[self._idx[field]] 360 return True 361 362 if result is False: 363 raise gmExceptions.ConstructorError("[%s:%s]: error loading instance" % (self.__class__.__name__, self.pk_obj))
364 365 #--------------------------------------------------------
366 - def _init_from_row_data(self, row=None):
367 """Creates a new clinical item instance given its fields. 368 369 row must be a dict with the fields: 370 - idx: a dict mapping field names to position 371 - data: the field values in a list (as returned by 372 cursor.fetchone() in the DB-API) 373 - pk_field: the name of the primary key field 374 OR 375 - pk_obj: a dictionary suitable for passed to cursor.execute 376 and holding the primary key values, used for composite PKs 377 378 row = { 379 'data': rows[0], 380 'idx': idx, 381 'pk_field': 'pk_XXX (the PK column name)', 382 'pk_obj': {'pk_col1': pk_col1_val, 'pk_col2': pk_col2_val} 383 } 384 rows, idx = gmPG2.run_ro_queries(queries = [{'cmd': cmd, 'args': args}], get_col_idx = True) 385 objects = [ cChildClass(row = {'data': r, 'idx': idx, 'pk_field': 'the PK column name'}) for r in rows ] 386 """ 387 assert ('data' in row), "[%s:??]: 'data' missing from <row> argument: %s" % (self.__class__.__name__, row) 388 assert ('idx' in row), "[%s:??]: 'idx' missing from <row> argument: %s" % (self.__class__.__name__, row) 389 assert (len(row['idx']) == len(row['data'])), "[%s:??]: 'idx'<->'data' field count mismatch: %s" % (self.__class__.__name__, row) 390 faulty_pk = (('pk_field' not in row) and ('pk_obj' not in row)) 391 assert not faulty_pk, "[%s:??]: either 'pk_field' or 'pk_obj' must exist in <row> argument: %s" % (self.__class__.__name__, row) 392 393 self._idx = row['idx'] 394 self._payload = row['data'] 395 if 'pk_field' in row: 396 self.pk_obj = row['data'][row['idx'][row['pk_field']]] 397 else: 398 self.pk_obj = row['pk_obj'] 399 400 self.payload_most_recently_fetched = {} 401 for field in self._idx.keys(): 402 self.payload_most_recently_fetched[field] = self._payload[self._idx[field]]
403 404 #--------------------------------------------------------
405 - def __del__(self):
406 if '_is_modified' in self.__dict__: 407 if self._is_modified: 408 _log.critical('[%s:%s]: loosing payload changes' % (self.__class__.__name__, self.pk_obj)) 409 _log.debug('most recently fetched: %s' % self.payload_most_recently_fetched) 410 _log.debug('modified: %s' % self._payload)
411 412 #--------------------------------------------------------
413 - def __str__(self):
414 lines = [] 415 try: 416 for attr in self._idx.keys(): 417 if self._payload[self._idx[attr]] is None: 418 lines.append('%s: NULL' % attr) 419 else: 420 lines.append('%s: %s [%s]' % ( 421 attr, 422 self._payload[self._idx[attr]], 423 type(self._payload[self._idx[attr]]) 424 )) 425 return '[%s:%s]:\n%s' % (self.__class__.__name__, self.pk_obj, '\n'.join(lines)) 426 except: 427 return 'likely nascent [%s @ %s], cannot show payload and primary key' %(self.__class__.__name__, id(self))
428 429 #--------------------------------------------------------
430 - def __getitem__(self, attribute):
431 # use try: except: as it is faster and we want this as fast as possible 432 433 # 1) backend payload cache 434 try: 435 return self._payload[self._idx[attribute]] 436 except KeyError: 437 pass 438 439 # 2) extension method results ... 440 getter = getattr(self, 'get_%s' % attribute, None) 441 if not callable(getter): 442 _log.warning('[%s]: no attribute [%s]' % (self.__class__.__name__, attribute)) 443 _log.warning('[%s]: valid attributes: %s' % (self.__class__.__name__, str(self._idx.keys()))) 444 _log.warning('[%s]: no getter method [get_%s]' % (self.__class__.__name__, attribute)) 445 methods = [ m for m in inspect.getmembers(self, inspect.ismethod) if m[0].startswith('get_') ] 446 _log.warning('[%s]: valid getter methods: %s' % (self.__class__.__name__, str(methods))) 447 raise KeyError('[%s]: cannot read from key [%s]' % (self.__class__.__name__, attribute)) 448 449 self._ext_cache[attribute] = getter() 450 return self._ext_cache[attribute]
451 #--------------------------------------------------------
452 - def __setitem__(self, attribute, value):
453 454 # 1) backend payload cache 455 if attribute in self.__class__._updatable_fields: 456 try: 457 if self._payload[self._idx[attribute]] != value: 458 self._payload[self._idx[attribute]] = value 459 self._is_modified = True 460 return 461 except KeyError: 462 _log.warning('[%s]: cannot set attribute <%s> despite marked settable' % (self.__class__.__name__, attribute)) 463 _log.warning('[%s]: supposedly settable attributes: %s' % (self.__class__.__name__, str(self.__class__._updatable_fields))) 464 raise KeyError('[%s]: cannot write to key [%s]' % (self.__class__.__name__, attribute)) 465 466 # 2) setters providing extensions 467 if hasattr(self, 'set_%s' % attribute): 468 setter = getattr(self, "set_%s" % attribute) 469 if not callable(setter): 470 raise AttributeError('[%s] setter [set_%s] not callable' % (self.__class__.__name__, attribute)) 471 try: 472 del self._ext_cache[attribute] 473 except KeyError: 474 pass 475 if type(value) == tuple: 476 if setter(*value): 477 self._is_modified = True 478 return 479 raise AttributeError('[%s]: setter [%s] failed for [%s]' % (self.__class__.__name__, setter, value)) 480 if setter(value): 481 self._is_modified = True 482 return 483 484 # 3) don't know what to do with <attribute> 485 _log.error('[%s]: cannot find attribute <%s> or setter method [set_%s]' % (self.__class__.__name__, attribute, attribute)) 486 _log.warning('[%s]: settable attributes: %s' % (self.__class__.__name__, str(self.__class__._updatable_fields))) 487 methods = [ m for m in inspect.getmembers(self, inspect.ismethod) if m[0].startswith('set_') ] 488 _log.warning('[%s]: valid setter methods: %s' % (self.__class__.__name__, str(methods))) 489 raise AttributeError('[%s]: cannot set [%s]' % (self.__class__.__name__, attribute))
490 491 #-------------------------------------------------------- 492 # external API 493 #--------------------------------------------------------
494 - def same_payload(self, another_object=None):
495 raise NotImplementedError('comparison between [%s] and [%s] not implemented' % (self, another_object))
496 497 #--------------------------------------------------------
498 - def is_modified(self):
499 return self._is_modified
500 501 #--------------------------------------------------------
502 - def get_fields(self):
503 try: 504 return self._idx.keys() 505 except AttributeError: 506 return 'nascent [%s @ %s], cannot return keys' %(self.__class__.__name__, id(self))
507 508 #--------------------------------------------------------
509 - def get_updatable_fields(self):
510 return self.__class__._updatable_fields
511 512 #--------------------------------------------------------
513 - def fields_as_dict(self, date_format='%Y %b %d %H:%M', none_string='', escape_style=None, bool_strings=None):
514 if bool_strings is None: 515 bools = {True: 'True', False: 'False'} 516 else: 517 bools = {True: bool_strings[0], False: bool_strings[1]} 518 data = {} 519 for field in self._idx.keys(): 520 # FIXME: harden against BYTEA fields 521 #if type(self._payload[self._idx[field]]) == ... 522 # data[field] = _('<%s bytes of binary data>') % len(self._payload[self._idx[field]]) 523 # continue 524 val = self._payload[self._idx[field]] 525 if val is None: 526 data[field] = none_string 527 continue 528 if isinstance(val, bool): 529 data[field] = bools[val] 530 continue 531 532 if isinstance(val, datetime.datetime): 533 if date_format is None: 534 data[field] = val 535 continue 536 data[field] = pydt_strftime(val, format = date_format) 537 if escape_style in ['latex', 'tex']: 538 data[field] = tex_escape_string(data[field]) 539 elif escape_style in ['xetex', 'xelatex']: 540 data[field] = xetex_escape_string(data[field]) 541 continue 542 543 try: 544 data[field] = str(val, encoding = 'utf8', errors = 'replace') 545 except TypeError: 546 try: 547 data[field] = str(val) 548 except (UnicodeDecodeError, TypeError): 549 val = '%s' % str(val) 550 data[field] = val.decode('utf8', 'replace') 551 if escape_style in ['latex', 'tex']: 552 data[field] = tex_escape_string(data[field]) 553 elif escape_style in ['xetex', 'xelatex']: 554 data[field] = xetex_escape_string(data[field]) 555 556 return data
557 558 #--------------------------------------------------------
559 - def get_patient(self):
560 _log.error('[%s:%s]: forgot to override get_patient()' % (self.__class__.__name__, self.pk_obj)) 561 return None
562 563 #--------------------------------------------------------
564 - def _get_patient_pk(self):
565 try: 566 return self._payload[self._idx['pk_patient']] 567 except KeyError: 568 pass 569 try: 570 return self._payload[self._idx['pk_identity']] 571 except KeyError: 572 return None
573 574 patient_pk = property(_get_patient_pk) 575 576 #--------------------------------------------------------
577 - def _get_staff_id(self):
578 try: 579 return self._payload[self._idx['pk_staff']] 580 except KeyError: 581 _log.debug('[%s]: .pk_staff should be added to the view', self.__class__.__name__) 582 try: 583 return self._payload[self._idx['pk_provider']] 584 except KeyError: 585 pass 586 mod_by = None 587 try: 588 mod_by = self._payload[self._idx['modified_by_raw']] 589 except KeyError: 590 _log.debug('[%s]: .modified_by_raw should be added to the view', self.__class__.__name__) 591 if mod_by is not None: 592 # find by DB account 593 args = {'db_u': mod_by} 594 cmd = "SELECT pk FROM dem.staff WHERE db_user = %(db_u)s" 595 rows, idx = gmPG2.run_ro_queries(queries = [{'cmd': cmd, 'args': args}], get_col_idx = False) 596 if len(rows) > 0: 597 # logically, they are all the same provider, because they share the DB account 598 return rows[0][0] 599 600 mod_by = self._payload[self._idx['modified_by']] 601 # is .modified_by a "<DB-account>" ? 602 if mod_by.startswith('<') and mod_by.endswith('>'): 603 # find by DB account 604 args = {'db_u': mod_by.lstrip('<').rstrip('>')} 605 cmd = "SELECT pk FROM dem.staff WHERE db_user = %(db_u)s" 606 rows, idx = gmPG2.run_ro_queries(queries = [{'cmd': cmd, 'args': args}], get_col_idx = False) 607 if len(rows) > 0: 608 # logically, they are all the same provider, because they share the DB account 609 return rows[0][0] 610 611 # .modified_by is probably dem.staff.short_alias 612 args = {'alias': mod_by} 613 cmd = "SELECT pk FROM dem.staff WHERE short_alias = %(alias)s" 614 rows, idx = gmPG2.run_ro_queries(queries = [{'cmd': cmd, 'args': args}], get_col_idx = False) 615 if len(rows) > 0: 616 # logically, they are all the same provider, because they share the DB account 617 return rows[0][0] 618 619 _log.error('[%s]: cannot retrieve staff ID for [%s]', self.__class__.__name__, mod_by) 620 return None
621 622 staff_id = property(_get_staff_id) 623 624 #--------------------------------------------------------
625 - def format(self, *args, **kwargs):
626 return format_dict_like ( 627 self.fields_as_dict(none_string = '<?>'), 628 tabular = True, 629 value_delimiters = None 630 ).split('\n')
631 632 #--------------------------------------------------------
633 - def _get_revision_history(self, query, args, title):
634 rows, idx = gmPG2.run_ro_queries(queries = [{'cmd': query, 'args': args}], get_col_idx = True) 635 636 lines = [] 637 if rows == 0: 638 lines.append('%s (no versions)' % title) 639 else: 640 lines.append('%s (%s versions)' % (title, rows[0]['row_version'] + 1)) 641 headers = [ 'rev %s (%s)' % (r['row_version'], pydt_strftime(r['audit__action_when'], format = '%Y %b %d %H:%M', none_str = 'live row')) for r in rows ] 642 lines.extend (dicts2table ( 643 rows, 644 left_margin = 1, 645 eol = None, 646 keys2ignore = ['audit__action_when', 'row_version', 'pk_audit'], 647 show_only_changes = True, 648 headers = headers, 649 date_format = '%Y %b %d %H:%M', 650 equality_value = u_left_arrow 651 )) 652 return lines
653 654 #--------------------------------------------------------
655 - def refetch_payload(self, ignore_changes=False, link_obj=None):
656 """Fetch field values from backend.""" 657 if self._is_modified: 658 compare_dict_likes(self.original_payload, self.fields_as_dict(date_format = None, none_string = None), 'original payload', 'modified payload') 659 if ignore_changes: 660 _log.critical('[%s:%s]: loosing payload changes' % (self.__class__.__name__, self.pk_obj)) 661 #_log.debug('most recently fetched: %s' % self.payload_most_recently_fetched) 662 #_log.debug('modified: %s' % self._payload) 663 else: 664 _log.critical('[%s:%s]: cannot reload, payload changed' % (self.__class__.__name__, self.pk_obj)) 665 return False 666 667 if isinstance(self.pk_obj, dict): 668 args = self.pk_obj 669 else: 670 args = [self.pk_obj] 671 rows, self._idx = gmPG2.run_ro_queries ( 672 link_obj = link_obj, 673 queries = [{'cmd': self.__class__._cmd_fetch_payload, 'args': args}], 674 get_col_idx = True 675 ) 676 if len(rows) == 0: 677 _log.error('[%s:%s]: no such instance' % (self.__class__.__name__, self.pk_obj)) 678 return False 679 if len(rows) > 1: 680 raise AssertionError('[%s:%s]: %s instances !' % (self.__class__.__name__, self.pk_obj, len(rows))) 681 self._payload = rows[0] 682 return True
683 684 #--------------------------------------------------------
685 - def __noop(self):
686 pass
687 688 #--------------------------------------------------------
689 - def save(self, conn=None):
690 return self.save_payload(conn = conn)
691 692 #--------------------------------------------------------
693 - def save_payload(self, conn=None):
694 """Store updated values (if any) in database. 695 696 Optionally accepts a pre-existing connection 697 - returns a tuple (<True|False>, <data>) 698 - True: success 699 - False: an error occurred 700 * data is (error, message) 701 * for error meanings see gmPG2.run_rw_queries() 702 """ 703 if not self._is_modified: 704 return (True, None) 705 706 args = {} 707 for field in self._idx.keys(): 708 args[field] = self._payload[self._idx[field]] 709 self.payload_most_recently_attempted_to_store = args 710 711 close_conn = self.__noop 712 if conn is None: 713 conn = gmPG2.get_connection(readonly=False) 714 close_conn = conn.close 715 716 queries = [] 717 for query in self.__class__._cmds_store_payload: 718 queries.append({'cmd': query, 'args': args}) 719 rows, idx = gmPG2.run_rw_queries ( 720 link_obj = conn, 721 queries = queries, 722 return_data = True, 723 get_col_idx = True 724 ) 725 726 # success ? 727 if len(rows) == 0: 728 # nothing updated - this can happen if: 729 # - someone else updated the row so XMIN does not match anymore 730 # - the PK went away (rows were deleted from under us) 731 # - another WHERE condition of the UPDATE did not produce any rows to update 732 # - savepoints are used since subtransactions may relevantly change the xmin/xmax ... 733 return (False, ('cannot update row', _('[%s:%s]: row not updated (nothing returned), row in use ?') % (self.__class__.__name__, self.pk_obj))) 734 735 # update cached values from should-be-first-and-only 736 # result row of last query, 737 # update all fields returned such that computed 738 # columns see their new values (given they are 739 # returned by the query) 740 row = rows[0] 741 for key in idx: 742 try: 743 self._payload[self._idx[key]] = row[idx[key]] 744 except KeyError: 745 conn.rollback() 746 close_conn() 747 _log.error('[%s:%s]: cannot update instance, XMIN refetch key mismatch on [%s]' % (self.__class__.__name__, self.pk_obj, key)) 748 _log.error('payload keys: %s' % str(self._idx)) 749 _log.error('XMIN refetch keys: %s' % str(idx)) 750 _log.error(args) 751 raise 752 753 # only at conn.commit() time will data actually 754 # get committed (and thusly trigger based notifications 755 # be sent out), so reset the local modification flag 756 # right before that 757 self._is_modified = False 758 conn.commit() 759 close_conn() 760 761 # update to new "original" payload 762 self.payload_most_recently_fetched = {} 763 for field in self._idx.keys(): 764 self.payload_most_recently_fetched[field] = self._payload[self._idx[field]] 765 766 return (True, None)
767 768 #============================================================ 769 if __name__ == '__main__': 770 771 if len(sys.argv) < 2: 772 sys.exit() 773 774 if sys.argv[1] != 'test': 775 sys.exit() 776 777 #--------------------------------------------------------
778 - class cTestObj(cBusinessDBObject):
779 _cmd_fetch_payload = None 780 _cmds_store_payload = None 781 _updatable_fields = [] 782 #----------------------------------------------------
783 - def get_something(self):
784 pass
785 #----------------------------------------------------
786 - def set_something(self):
787 pass
788 #-------------------------------------------------------- 789 from Gnumed.pycommon import gmI18N 790 gmI18N.activate_locale() 791 gmI18N.install_domain() 792 793 data = { 794 'pk_field': 'bogus_pk', 795 'idx': {'bogus_pk': 0, 'bogus_field': 1, 'bogus_date': 2}, 796 'data': [-1, 'bogus_data', datetime.datetime.now()] 797 #'data': {'bogus_pk': -1, 'bogus_field': 'bogus_data', 'bogus_date': datetime.datetime.now()} 798 } 799 obj = cTestObj(row=data) 800 print(obj.format()) 801 #print(obj['wrong_field']) 802 #obj['wrong_field'] = 1 803 print(obj.fields_as_dict()) 804 805 #============================================================ 806