1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>
Interfaces
— SQLAlchemy 0.6.3 Documentation</title>
<link rel="stylesheet" href="../../_static/pygments.css" type="text/css" />
<link rel="stylesheet" href="../../_static/docs.css" type="text/css" />
<script type="text/javascript">
var DOCUMENTATION_OPTIONS = {
URL_ROOT: '../../',
VERSION: '0.6.3',
COLLAPSE_MODINDEX: false,
FILE_SUFFIX: '.html'
};
</script>
<script type="text/javascript" src="../../_static/jquery.js"></script>
<script type="text/javascript" src="../../_static/underscore.js"></script>
<script type="text/javascript" src="../../_static/doctools.js"></script>
<script type="text/javascript" src="../../_static/init.js"></script>
<link rel="index" title="Index" href="../../genindex.html" />
<link rel="search" title="Search" href="../../search.html" />
<link rel="top" title="SQLAlchemy 0.6.3 Documentation" href="../../index.html" />
<link rel="up" title="sqlalchemy.orm" href="index.html" />
<link rel="next" title="Utilities" href="utilities.html" />
<link rel="prev" title="Sessions" href="sessions.html" />
</head>
<body>
<h1>SQLAlchemy 0.6.3 Documentation</h1>
<div id="search">
Search:
<form class="search" action="../../search.html" method="get">
<input type="text" name="q" size="18" /> <input type="submit" value="Search" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
</div>
<div class="versionheader">
Version: <span class="versionnum">0.6.3</span> Last Updated: 07/15/2010 12:35:47
</div>
<div class="clearboth"></div>
<div class="topnav">
<div id="pagecontrol">
<a href="../index.html">API Reference</a>
|
<a href="../../genindex.html">Index</a>
<div class="sourcelink">(<a href="../../_sources/reference/orm/interfaces.txt">view source)</div>
</div>
<div class="navbanner">
<a class="totoc" href="../../index.html">Table of Contents</a>
» <a href="../index.html" title="API Reference">API Reference</a>
» <a href="index.html" title="sqlalchemy.orm">sqlalchemy.orm</a>
»
Interfaces
<div class="prevnext">
Previous:
<a href="sessions.html" title="previous chapter">Sessions</a>
Next:
<a href="utilities.html" title="next chapter">Utilities</a>
</div>
<h2>
Interfaces
</h2>
</div>
<div class="clearboth"></div>
</div>
<div class="document">
<div class="body">
<div class="section" id="module-sqlalchemy.orm.interfaces">
<span id="interfaces"></span><h1>Interfaces<a class="headerlink" href="#module-sqlalchemy.orm.interfaces" title="Permalink to this headline">¶</a></h1>
<p>Semi-private module containing various base classes used throughout the ORM.</p>
<p>Defines the extension classes <a class="reference internal" href="#sqlalchemy.orm.interfaces.MapperExtension" title="sqlalchemy.orm.interfaces.MapperExtension"><tt class="xref py py-class docutils literal"><span class="pre">MapperExtension</span></tt></a>,
<a class="reference internal" href="#sqlalchemy.orm.interfaces.SessionExtension" title="sqlalchemy.orm.interfaces.SessionExtension"><tt class="xref py py-class docutils literal"><span class="pre">SessionExtension</span></tt></a>, and <a class="reference internal" href="#sqlalchemy.orm.interfaces.AttributeExtension" title="sqlalchemy.orm.interfaces.AttributeExtension"><tt class="xref py py-class docutils literal"><span class="pre">AttributeExtension</span></tt></a> as
well as other user-subclassable extension objects.</p>
<dl class="class">
<dt id="sqlalchemy.orm.interfaces.AttributeExtension">
<em class="property">class </em><tt class="descclassname">sqlalchemy.orm.interfaces.</tt><tt class="descname">AttributeExtension</tt><a class="headerlink" href="#sqlalchemy.orm.interfaces.AttributeExtension" title="Permalink to this definition">¶</a></dt>
<dd><p>An event handler for individual attribute change events.</p>
<p>AttributeExtension is assembled within the descriptors associated
with a mapped class.</p>
<dl class="attribute">
<dt id="sqlalchemy.orm.interfaces.AttributeExtension.active_history">
<tt class="descname">active_history</tt><a class="headerlink" href="#sqlalchemy.orm.interfaces.AttributeExtension.active_history" title="Permalink to this definition">¶</a></dt>
<dd><p>indicates that the set() method would like to receive the ‘old’ value,
even if it means firing lazy callables.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.AttributeExtension.append">
<tt class="descname">append</tt><big>(</big><em>state</em>, <em>value</em>, <em>initiator</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.AttributeExtension.append" title="Permalink to this definition">¶</a></dt>
<dd><p>Receive a collection append event.</p>
<p>The returned value will be used as the actual value to be
appended.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.AttributeExtension.remove">
<tt class="descname">remove</tt><big>(</big><em>state</em>, <em>value</em>, <em>initiator</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.AttributeExtension.remove" title="Permalink to this definition">¶</a></dt>
<dd><p>Receive a remove event.</p>
<p>No return value is defined.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.AttributeExtension.set">
<tt class="descname">set</tt><big>(</big><em>state</em>, <em>value</em>, <em>oldvalue</em>, <em>initiator</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.AttributeExtension.set" title="Permalink to this definition">¶</a></dt>
<dd><p>Receive a set event.</p>
<p>The returned value will be used as the actual value to be
set.</p>
</dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager">
<em class="property">class </em><tt class="descclassname">sqlalchemy.orm.interfaces.</tt><tt class="descname">InstrumentationManager</tt><big>(</big><em>class_</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager" title="Permalink to this definition">¶</a></dt>
<dd><p>User-defined class instrumentation extension.</p>
<p>The API for this class should be considered as semi-stable,
and may change slightly with new releases.</p>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.__init__">
<tt class="descname">__init__</tt><big>(</big><em>class_</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.__init__" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.dict_getter">
<tt class="descname">dict_getter</tt><big>(</big><em>class_</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.dict_getter" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.dispose">
<tt class="descname">dispose</tt><big>(</big><em>class_</em>, <em>manager</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.dispose" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.get_instance_dict">
<tt class="descname">get_instance_dict</tt><big>(</big><em>class_</em>, <em>instance</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.get_instance_dict" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.initialize_instance_dict">
<tt class="descname">initialize_instance_dict</tt><big>(</big><em>class_</em>, <em>instance</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.initialize_instance_dict" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.install_descriptor">
<tt class="descname">install_descriptor</tt><big>(</big><em>class_</em>, <em>key</em>, <em>inst</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.install_descriptor" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.install_member">
<tt class="descname">install_member</tt><big>(</big><em>class_</em>, <em>key</em>, <em>implementation</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.install_member" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.install_state">
<tt class="descname">install_state</tt><big>(</big><em>class_</em>, <em>instance</em>, <em>state</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.install_state" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.instrument_attribute">
<tt class="descname">instrument_attribute</tt><big>(</big><em>class_</em>, <em>key</em>, <em>inst</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.instrument_attribute" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.instrument_collection_class">
<tt class="descname">instrument_collection_class</tt><big>(</big><em>class_</em>, <em>key</em>, <em>collection_class</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.instrument_collection_class" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.manage">
<tt class="descname">manage</tt><big>(</big><em>class_</em>, <em>manager</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.manage" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.manager_getter">
<tt class="descname">manager_getter</tt><big>(</big><em>class_</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.manager_getter" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.post_configure_attribute">
<tt class="descname">post_configure_attribute</tt><big>(</big><em>class_</em>, <em>key</em>, <em>inst</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.post_configure_attribute" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.remove_state">
<tt class="descname">remove_state</tt><big>(</big><em>class_</em>, <em>instance</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.remove_state" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.state_getter">
<tt class="descname">state_getter</tt><big>(</big><em>class_</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.state_getter" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.uninstall_descriptor">
<tt class="descname">uninstall_descriptor</tt><big>(</big><em>class_</em>, <em>key</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.uninstall_descriptor" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.InstrumentationManager.uninstall_member">
<tt class="descname">uninstall_member</tt><big>(</big><em>class_</em>, <em>key</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.InstrumentationManager.uninstall_member" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.orm.interfaces.MapperExtension">
<em class="property">class </em><tt class="descclassname">sqlalchemy.orm.interfaces.</tt><tt class="descname">MapperExtension</tt><a class="headerlink" href="#sqlalchemy.orm.interfaces.MapperExtension" title="Permalink to this definition">¶</a></dt>
<dd><p>Base implementation for customizing <tt class="docutils literal"><span class="pre">Mapper</span></tt> behavior.</p>
<p>New extension classes subclass <tt class="docutils literal"><span class="pre">MapperExtension</span></tt> and are specified
using the <tt class="docutils literal"><span class="pre">extension</span></tt> mapper() argument, which is a single
<tt class="docutils literal"><span class="pre">MapperExtension</span></tt> or a list of such. A single mapper
can maintain a chain of <tt class="docutils literal"><span class="pre">MapperExtension</span></tt> objects. When a
particular mapping event occurs, the corresponding method
on each <tt class="docutils literal"><span class="pre">MapperExtension</span></tt> is invoked serially, and each method
has the ability to halt the chain from proceeding further.</p>
<p>Each <tt class="docutils literal"><span class="pre">MapperExtension</span></tt> method returns the symbol
EXT_CONTINUE by default. This symbol generally means “move
to the next <tt class="docutils literal"><span class="pre">MapperExtension</span></tt> for processing”. For methods
that return objects like translated rows or new object
instances, EXT_CONTINUE means the result of the method
should be ignored. In some cases it’s required for a
default mapper activity to be performed, such as adding a
new instance to a result list.</p>
<p>The symbol EXT_STOP has significance within a chain
of <tt class="docutils literal"><span class="pre">MapperExtension</span></tt> objects that the chain will be stopped
when this symbol is returned. Like EXT_CONTINUE, it also
has additional significance in some cases that a default
mapper activity will not be performed.</p>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.MapperExtension.after_delete">
<tt class="descname">after_delete</tt><big>(</big><em>mapper</em>, <em>connection</em>, <em>instance</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.MapperExtension.after_delete" title="Permalink to this definition">¶</a></dt>
<dd><p>Receive an object instance after that instance is deleted.</p>
<p>The return value is only significant within the <tt class="docutils literal"><span class="pre">MapperExtension</span></tt>
chain; the parent mapper’s behavior isn’t modified by this method.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.MapperExtension.after_insert">
<tt class="descname">after_insert</tt><big>(</big><em>mapper</em>, <em>connection</em>, <em>instance</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.MapperExtension.after_insert" title="Permalink to this definition">¶</a></dt>
<dd><p>Receive an object instance after that instance is inserted.</p>
<p>The return value is only significant within the <tt class="docutils literal"><span class="pre">MapperExtension</span></tt>
chain; the parent mapper’s behavior isn’t modified by this method.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.MapperExtension.after_update">
<tt class="descname">after_update</tt><big>(</big><em>mapper</em>, <em>connection</em>, <em>instance</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.MapperExtension.after_update" title="Permalink to this definition">¶</a></dt>
<dd><p>Receive an object instance after that instance is updated.</p>
<p>The return value is only significant within the <tt class="docutils literal"><span class="pre">MapperExtension</span></tt>
chain; the parent mapper’s behavior isn’t modified by this method.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.MapperExtension.append_result">
<tt class="descname">append_result</tt><big>(</big><em>mapper</em>, <em>selectcontext</em>, <em>row</em>, <em>instance</em>, <em>result</em>, <em>**flags</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.MapperExtension.append_result" title="Permalink to this definition">¶</a></dt>
<dd><p>Receive an object instance before that instance is appended
to a result list.</p>
<p>If this method returns EXT_CONTINUE, result appending will proceed
normally. if this method returns any other value or None,
result appending will not proceed for this instance, giving
this extension an opportunity to do the appending itself, if
desired.</p>
<dl class="docutils">
<dt>mapper</dt>
<dd>The mapper doing the operation.</dd>
<dt>selectcontext</dt>
<dd>The QueryContext generated from the Query.</dd>
<dt>row</dt>
<dd>The result row from the database.</dd>
<dt>instance</dt>
<dd>The object instance to be appended to the result.</dd>
<dt>result</dt>
<dd>List to which results are being appended.</dd>
<dt>**flags</dt>
<dd><p class="first">extra information about the row, same as criterion in
<tt class="docutils literal"><span class="pre">create_row_processor()</span></tt> method of</p>
<blockquote class="last">
<a class="reference internal" href="mapping.html#sqlalchemy.orm.interfaces.MapperProperty" title="sqlalchemy.orm.interfaces.MapperProperty"><tt class="xref py py-class docutils literal"><span class="pre">MapperProperty</span></tt></a></blockquote>
</dd>
</dl>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.MapperExtension.before_delete">
<tt class="descname">before_delete</tt><big>(</big><em>mapper</em>, <em>connection</em>, <em>instance</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.MapperExtension.before_delete" title="Permalink to this definition">¶</a></dt>
<dd><p>Receive an object instance before that instance is deleted.</p>
<p>Note that <em>no</em> changes to the overall flush plan can be made
here; and manipulation of the <tt class="docutils literal"><span class="pre">Session</span></tt> will not have the
desired effect. To manipulate the <tt class="docutils literal"><span class="pre">Session</span></tt> within an
extension, use <tt class="docutils literal"><span class="pre">SessionExtension</span></tt>.</p>
<p>The return value is only significant within the <tt class="docutils literal"><span class="pre">MapperExtension</span></tt>
chain; the parent mapper’s behavior isn’t modified by this method.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.MapperExtension.before_insert">
<tt class="descname">before_insert</tt><big>(</big><em>mapper</em>, <em>connection</em>, <em>instance</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.MapperExtension.before_insert" title="Permalink to this definition">¶</a></dt>
<dd><p>Receive an object instance before that instance is inserted
into its table.</p>
<p>This is a good place to set up primary key values and such
that aren’t handled otherwise.</p>
<p>Column-based attributes can be modified within this method
which will result in the new value being inserted. However
<em>no</em> changes to the overall flush plan can be made, and
manipulation of the <tt class="docutils literal"><span class="pre">Session</span></tt> will not have the desired effect.
To manipulate the <tt class="docutils literal"><span class="pre">Session</span></tt> within an extension, use
<tt class="docutils literal"><span class="pre">SessionExtension</span></tt>.</p>
<p>The return value is only significant within the <tt class="docutils literal"><span class="pre">MapperExtension</span></tt>
chain; the parent mapper’s behavior isn’t modified by this method.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.MapperExtension.before_update">
<tt class="descname">before_update</tt><big>(</big><em>mapper</em>, <em>connection</em>, <em>instance</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.MapperExtension.before_update" title="Permalink to this definition">¶</a></dt>
<dd><p>Receive an object instance before that instance is updated.</p>
<p>Note that this method is called for all instances that are marked as
“dirty”, even those which have no net changes to their column-based
attributes. An object is marked as dirty when any of its column-based
attributes have a “set attribute” operation called or when any of its
collections are modified. If, at update time, no column-based
attributes have any net changes, no UPDATE statement will be issued.
This means that an instance being sent to before_update is <em>not</em> a
guarantee that an UPDATE statement will be issued (although you can
affect the outcome here).</p>
<p>To detect if the column-based attributes on the object have net
changes, and will therefore generate an UPDATE statement, use
<tt class="docutils literal"><span class="pre">object_session(instance).is_modified(instance,</span>
<span class="pre">include_collections=False)</span></tt>.</p>
<p>Column-based attributes can be modified within this method
which will result in the new value being updated. However
<em>no</em> changes to the overall flush plan can be made, and
manipulation of the <tt class="docutils literal"><span class="pre">Session</span></tt> will not have the desired effect.
To manipulate the <tt class="docutils literal"><span class="pre">Session</span></tt> within an extension, use
<tt class="docutils literal"><span class="pre">SessionExtension</span></tt>.</p>
<p>The return value is only significant within the <tt class="docutils literal"><span class="pre">MapperExtension</span></tt>
chain; the parent mapper’s behavior isn’t modified by this method.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.MapperExtension.create_instance">
<tt class="descname">create_instance</tt><big>(</big><em>mapper</em>, <em>selectcontext</em>, <em>row</em>, <em>class_</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.MapperExtension.create_instance" title="Permalink to this definition">¶</a></dt>
<dd><p>Receive a row when a new object instance is about to be
created from that row.</p>
<p>The method can choose to create the instance itself, or it can return
EXT_CONTINUE to indicate normal object creation should take place.</p>
<dl class="docutils">
<dt>mapper</dt>
<dd>The mapper doing the operation</dd>
<dt>selectcontext</dt>
<dd>The QueryContext generated from the Query.</dd>
<dt>row</dt>
<dd>The result row from the database</dd>
<dt>class_</dt>
<dd>The class we are mapping.</dd>
<dt>return value</dt>
<dd>A new object instance, or EXT_CONTINUE</dd>
</dl>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.MapperExtension.init_failed">
<tt class="descname">init_failed</tt><big>(</big><em>mapper</em>, <em>class_</em>, <em>oldinit</em>, <em>instance</em>, <em>args</em>, <em>kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.MapperExtension.init_failed" title="Permalink to this definition">¶</a></dt>
<dd><p>Receive an instance when it’s constructor has been called,
and raised an exception.</p>
<p>This method is only called during a userland construction of
an object. It is not called when an object is loaded from the
database.</p>
<p>The return value is only significant within the <tt class="docutils literal"><span class="pre">MapperExtension</span></tt>
chain; the parent mapper’s behavior isn’t modified by this method.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.MapperExtension.init_instance">
<tt class="descname">init_instance</tt><big>(</big><em>mapper</em>, <em>class_</em>, <em>oldinit</em>, <em>instance</em>, <em>args</em>, <em>kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.MapperExtension.init_instance" title="Permalink to this definition">¶</a></dt>
<dd><p>Receive an instance when it’s constructor is called.</p>
<p>This method is only called during a userland construction of
an object. It is not called when an object is loaded from the
database.</p>
<p>The return value is only significant within the <tt class="docutils literal"><span class="pre">MapperExtension</span></tt>
chain; the parent mapper’s behavior isn’t modified by this method.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.MapperExtension.instrument_class">
<tt class="descname">instrument_class</tt><big>(</big><em>mapper</em>, <em>class_</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.MapperExtension.instrument_class" title="Permalink to this definition">¶</a></dt>
<dd><p>Receive a class when the mapper is first constructed, and has
applied instrumentation to the mapped class.</p>
<p>The return value is only significant within the <tt class="docutils literal"><span class="pre">MapperExtension</span></tt>
chain; the parent mapper’s behavior isn’t modified by this method.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.MapperExtension.populate_instance">
<tt class="descname">populate_instance</tt><big>(</big><em>mapper</em>, <em>selectcontext</em>, <em>row</em>, <em>instance</em>, <em>**flags</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.MapperExtension.populate_instance" title="Permalink to this definition">¶</a></dt>
<dd><p>Receive an instance before that instance has
its attributes populated.</p>
<p>This usually corresponds to a newly loaded instance but may
also correspond to an already-loaded instance which has
unloaded attributes to be populated. The method may be called
many times for a single instance, as multiple result rows are
used to populate eagerly loaded collections.</p>
<p>If this method returns EXT_CONTINUE, instance population will
proceed normally. If any other value or None is returned,
instance population will not proceed, giving this extension an
opportunity to populate the instance itself, if desired.</p>
<p>As of 0.5, most usages of this hook are obsolete. For a
generic “object has been newly created from a row” hook, use
<tt class="docutils literal"><span class="pre">reconstruct_instance()</span></tt>, or the <tt class="docutils literal"><span class="pre">@orm.reconstructor</span></tt>
decorator.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.MapperExtension.reconstruct_instance">
<tt class="descname">reconstruct_instance</tt><big>(</big><em>mapper</em>, <em>instance</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.MapperExtension.reconstruct_instance" title="Permalink to this definition">¶</a></dt>
<dd><p>Receive an object instance after it has been created via
<tt class="docutils literal"><span class="pre">__new__</span></tt>, and after initial attribute population has
occurred.</p>
<p>This typically occurs when the instance is created based on
incoming result rows, and is only called once for that
instance’s lifetime.</p>
<p>Note that during a result-row load, this method is called upon
the first row received for this instance. Note that some
attributes and collections may or may not be loaded or even
initialized, depending on what’s present in the result rows.</p>
<p>The return value is only significant within the <tt class="docutils literal"><span class="pre">MapperExtension</span></tt>
chain; the parent mapper’s behavior isn’t modified by this method.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.MapperExtension.translate_row">
<tt class="descname">translate_row</tt><big>(</big><em>mapper</em>, <em>context</em>, <em>row</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.MapperExtension.translate_row" title="Permalink to this definition">¶</a></dt>
<dd><p>Perform pre-processing on the given result row and return a
new row instance.</p>
<p>This is called when the mapper first receives a row, before
the object identity or the instance itself has been derived
from that row. The given row may or may not be a
<tt class="docutils literal"><span class="pre">RowProxy</span></tt> object - it will always be a dictionary-like
object which contains mapped columns as keys. The
returned object should also be a dictionary-like object
which recognizes mapped columns as keys.</p>
<p>If the ultimate return value is EXT_CONTINUE, the row
is not translated.</p>
</dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.orm.interfaces.PropComparator">
<em class="property">class </em><tt class="descclassname">sqlalchemy.orm.interfaces.</tt><tt class="descname">PropComparator</tt><big>(</big><em>prop</em>, <em>mapper</em>, <em>adapter=None</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.PropComparator" title="Permalink to this definition">¶</a></dt>
<dd><p>defines comparison operations for MapperProperty objects.</p>
<p>PropComparator instances should also define an accessor ‘property’
which returns the MapperProperty associated with this
PropComparator.</p>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.PropComparator.__init__">
<tt class="descname">__init__</tt><big>(</big><em>prop</em>, <em>mapper</em>, <em>adapter=None</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.PropComparator.__init__" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.PropComparator.adapted">
<tt class="descname">adapted</tt><big>(</big><em>adapter</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.PropComparator.adapted" title="Permalink to this definition">¶</a></dt>
<dd><p>Return a copy of this PropComparator which will use the given
adaption function on the local side of generated expressions.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.PropComparator.any">
<tt class="descname">any</tt><big>(</big><em>criterion=None</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.PropComparator.any" title="Permalink to this definition">¶</a></dt>
<dd><p>Return true if this collection contains any member that meets the
given criterion.</p>
<dl class="docutils">
<dt>criterion</dt>
<dd>an optional ClauseElement formulated against the member class’ table
or attributes.</dd>
<dt>**kwargs</dt>
<dd>key/value pairs corresponding to member class attribute names which
will be compared via equality to the corresponding values.</dd>
</dl>
</dd></dl>
<dl class="staticmethod">
<dt id="sqlalchemy.orm.interfaces.PropComparator.any_op">
<em class="property">static </em><tt class="descname">any_op</tt><big>(</big><em>a</em>, <em>b</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.PropComparator.any_op" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.PropComparator.has">
<tt class="descname">has</tt><big>(</big><em>criterion=None</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.PropComparator.has" title="Permalink to this definition">¶</a></dt>
<dd><p>Return true if this element references a member which meets the
given criterion.</p>
<dl class="docutils">
<dt>criterion</dt>
<dd>an optional ClauseElement formulated against the member class’ table
or attributes.</dd>
<dt>**kwargs</dt>
<dd>key/value pairs corresponding to member class attribute names which
will be compared via equality to the corresponding values.</dd>
</dl>
</dd></dl>
<dl class="staticmethod">
<dt id="sqlalchemy.orm.interfaces.PropComparator.has_op">
<em class="property">static </em><tt class="descname">has_op</tt><big>(</big><em>a</em>, <em>b</em>, <em>**kwargs</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.PropComparator.has_op" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.PropComparator.of_type">
<tt class="descname">of_type</tt><big>(</big><em>class_</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.PropComparator.of_type" title="Permalink to this definition">¶</a></dt>
<dd><p>Redefine this object in terms of a polymorphic subclass.</p>
<p>Returns a new PropComparator from which further criterion can be
evaluated.</p>
<p>e.g.:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="n">query</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">Company</span><span class="o">.</span><span class="n">employees</span><span class="o">.</span><span class="n">of_type</span><span class="p">(</span><span class="n">Engineer</span><span class="p">))</span><span class="o">.</span>\
<span class="nb">filter</span><span class="p">(</span><span class="n">Engineer</span><span class="o">.</span><span class="n">name</span><span class="o">==</span><span class="s">'foo'</span><span class="p">)</span></pre></div>
</div>
<dl class="docutils">
<dt>class_</dt>
<dd>a class or mapper indicating that criterion will be against
this specific subclass.</dd>
</dl>
</dd></dl>
<dl class="staticmethod">
<dt id="sqlalchemy.orm.interfaces.PropComparator.of_type_op">
<em class="property">static </em><tt class="descname">of_type_op</tt><big>(</big><em>a</em>, <em>class_</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.PropComparator.of_type_op" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
</dd></dl>
<dl class="class">
<dt id="sqlalchemy.orm.interfaces.SessionExtension">
<em class="property">class </em><tt class="descclassname">sqlalchemy.orm.interfaces.</tt><tt class="descname">SessionExtension</tt><a class="headerlink" href="#sqlalchemy.orm.interfaces.SessionExtension" title="Permalink to this definition">¶</a></dt>
<dd><p>An extension hook object for Sessions. Subclasses may be
installed into a Session (or sessionmaker) using the <tt class="docutils literal"><span class="pre">extension</span></tt>
keyword argument.</p>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.SessionExtension.after_attach">
<tt class="descname">after_attach</tt><big>(</big><em>session</em>, <em>instance</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.SessionExtension.after_attach" title="Permalink to this definition">¶</a></dt>
<dd><p>Execute after an instance is attached to a session.</p>
<p>This is called after an add, delete or merge.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.SessionExtension.after_begin">
<tt class="descname">after_begin</tt><big>(</big><em>session</em>, <em>transaction</em>, <em>connection</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.SessionExtension.after_begin" title="Permalink to this definition">¶</a></dt>
<dd><p>Execute after a transaction is begun on a connection</p>
<p><cite>transaction</cite> is the SessionTransaction. This method is called
after an engine level transaction is begun on a connection.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.SessionExtension.after_bulk_delete">
<tt class="descname">after_bulk_delete</tt><big>(</big><em>session</em>, <em>query</em>, <em>query_context</em>, <em>result</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.SessionExtension.after_bulk_delete" title="Permalink to this definition">¶</a></dt>
<dd><p>Execute after a bulk delete operation to the session.</p>
<p>This is called after a session.query(...).delete()</p>
<p><cite>query</cite> is the query object that this delete operation was
called on. <cite>query_context</cite> was the query context object.
<cite>result</cite> is the result object returned from the bulk operation.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.SessionExtension.after_bulk_update">
<tt class="descname">after_bulk_update</tt><big>(</big><em>session</em>, <em>query</em>, <em>query_context</em>, <em>result</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.SessionExtension.after_bulk_update" title="Permalink to this definition">¶</a></dt>
<dd><p>Execute after a bulk update operation to the session.</p>
<p>This is called after a session.query(...).update()</p>
<p><cite>query</cite> is the query object that this update operation was
called on. <cite>query_context</cite> was the query context object.
<cite>result</cite> is the result object returned from the bulk operation.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.SessionExtension.after_commit">
<tt class="descname">after_commit</tt><big>(</big><em>session</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.SessionExtension.after_commit" title="Permalink to this definition">¶</a></dt>
<dd><p>Execute after a commit has occured.</p>
<p>Note that this may not be per-flush if a longer running
transaction is ongoing.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.SessionExtension.after_flush">
<tt class="descname">after_flush</tt><big>(</big><em>session</em>, <em>flush_context</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.SessionExtension.after_flush" title="Permalink to this definition">¶</a></dt>
<dd><p>Execute after flush has completed, but before commit has been
called.</p>
<p>Note that the session’s state is still in pre-flush, i.e. ‘new’,
‘dirty’, and ‘deleted’ lists still show pre-flush state as well
as the history settings on instance attributes.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.SessionExtension.after_flush_postexec">
<tt class="descname">after_flush_postexec</tt><big>(</big><em>session</em>, <em>flush_context</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.SessionExtension.after_flush_postexec" title="Permalink to this definition">¶</a></dt>
<dd><p>Execute after flush has completed, and after the post-exec
state occurs.</p>
<p>This will be when the ‘new’, ‘dirty’, and ‘deleted’ lists are in
their final state. An actual commit() may or may not have
occured, depending on whether or not the flush started its own
transaction or participated in a larger transaction.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.SessionExtension.after_rollback">
<tt class="descname">after_rollback</tt><big>(</big><em>session</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.SessionExtension.after_rollback" title="Permalink to this definition">¶</a></dt>
<dd><p>Execute after a rollback has occured.</p>
<p>Note that this may not be per-flush if a longer running
transaction is ongoing.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.SessionExtension.before_commit">
<tt class="descname">before_commit</tt><big>(</big><em>session</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.SessionExtension.before_commit" title="Permalink to this definition">¶</a></dt>
<dd><p>Execute right before commit is called.</p>
<p>Note that this may not be per-flush if a longer running
transaction is ongoing.</p>
</dd></dl>
<dl class="method">
<dt id="sqlalchemy.orm.interfaces.SessionExtension.before_flush">
<tt class="descname">before_flush</tt><big>(</big><em>session</em>, <em>flush_context</em>, <em>instances</em><big>)</big><a class="headerlink" href="#sqlalchemy.orm.interfaces.SessionExtension.before_flush" title="Permalink to this definition">¶</a></dt>
<dd><p>Execute before flush process has started.</p>
<p><cite>instances</cite> is an optional list of objects which were passed to
the <tt class="docutils literal"><span class="pre">flush()</span></tt> method.</p>
</dd></dl>
</dd></dl>
</div>
</div>
</div>
<div class="bottomnav">
<div class="prevnext">
Previous:
<a href="sessions.html" title="previous chapter">Sessions</a>
Next:
<a href="utilities.html" title="next chapter">Utilities</a>
</div>
<div class="doc_copyright">
© Copyright 2007, 2008, 2009, 2010, the SQLAlchemy authors and contributors.
Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.0b2+.
</div>
</div>
</body>
</html>
|
