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
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
|
<!DOCTYPE html>
<html class="writer-html5" lang="en" data-content_root="./">
<head>
<meta charset="utf-8" /><meta name="viewport" content="width=device-width, initial-scale=1" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Virtual Tables — APSW 3.46.0.1 documentation</title>
<link rel="stylesheet" type="text/css" href="_static/pygments.css?v=72bcf2f2" />
<link rel="stylesheet" type="text/css" href="_static/css/theme.css?v=19f00094" />
<link rel="stylesheet" type="text/css" href="_static/apsw.css?v=3c7e2631" />
<link rel="shortcut icon" href="_static/favicon.ico"/>
<!--[if lt IE 9]>
<script src="_static/js/html5shiv.min.js"></script>
<![endif]-->
<script src="_static/jquery.js?v=5d32c60e"></script>
<script src="_static/_sphinx_javascript_frameworks_compat.js?v=2cd50e6c"></script>
<script src="_static/documentation_options.js?v=d98f5d2b"></script>
<script src="_static/doctools.js?v=9a2dae69"></script>
<script src="_static/sphinx_highlight.js?v=dc90522c"></script>
<script src="_static/js/theme.js"></script>
<link rel="author" title="About these documents" href="about.html" />
<link rel="index" title="Index" href="genindex.html" />
<link rel="search" title="Search" href="search.html" />
<link rel="copyright" title="Copyright" href="copyright.html" />
<link rel="next" title="Virtual File System (VFS)" href="vfs.html" />
<link rel="prev" title="Backup" href="backup.html" />
</head>
<body class="wy-body-for-nav">
<div class="wy-grid-for-nav">
<nav data-toggle="wy-nav-shift" class="wy-nav-side">
<div class="wy-side-scroll">
<div class="wy-side-nav-search" >
<a href="index.html" class="icon icon-home">
APSW
<img src="_static/apswlogo.png" class="logo" alt="Logo"/>
</a>
<div class="version">
3.46.0.1
</div>
<div role="search">
<form id="rtd-search-form" class="wy-form" action="search.html" method="get">
<input type="text" name="q" placeholder="Search docs" aria-label="Search docs" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
</div>
</div><div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="Navigation menu">
<ul class="current">
<li class="toctree-l1"><a class="reference internal" href="about.html">About</a></li>
<li class="toctree-l1"><a class="reference internal" href="tips.html">Tips</a></li>
<li class="toctree-l1"><a class="reference internal" href="example.html">Example/Tour</a></li>
<li class="toctree-l1"><a class="reference internal" href="install.html">Installation and customization</a></li>
<li class="toctree-l1"><a class="reference internal" href="extensions.html">Extensions</a></li>
<li class="toctree-l1"><a class="reference internal" href="apsw.html">APSW Module</a></li>
<li class="toctree-l1"><a class="reference internal" href="connection.html">Connections to a database</a></li>
<li class="toctree-l1"><a class="reference internal" href="cursor.html">Cursors (executing SQL)</a></li>
<li class="toctree-l1"><a class="reference internal" href="blob.html">Blob Input/Output</a></li>
<li class="toctree-l1"><a class="reference internal" href="backup.html">Backup</a></li>
<li class="toctree-l1 current"><a class="current reference internal" href="#">Virtual Tables</a><ul>
<li class="toctree-l2"><a class="reference internal" href="#indexinfo-class">IndexInfo class</a><ul>
<li class="toctree-l3"><a class="reference internal" href="#apsw.IndexInfo"><code class="docutils literal notranslate"><span class="pre">IndexInfo</span></code></a><ul>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.colUsed"><code class="docutils literal notranslate"><span class="pre">IndexInfo.colUsed</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.distinct"><code class="docutils literal notranslate"><span class="pre">IndexInfo.distinct</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.estimatedCost"><code class="docutils literal notranslate"><span class="pre">IndexInfo.estimatedCost</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.estimatedRows"><code class="docutils literal notranslate"><span class="pre">IndexInfo.estimatedRows</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.get_aConstraintUsage_argvIndex"><code class="docutils literal notranslate"><span class="pre">IndexInfo.get_aConstraintUsage_argvIndex()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.get_aConstraintUsage_in"><code class="docutils literal notranslate"><span class="pre">IndexInfo.get_aConstraintUsage_in()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.get_aConstraintUsage_omit"><code class="docutils literal notranslate"><span class="pre">IndexInfo.get_aConstraintUsage_omit()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.get_aConstraint_collation"><code class="docutils literal notranslate"><span class="pre">IndexInfo.get_aConstraint_collation()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.get_aConstraint_iColumn"><code class="docutils literal notranslate"><span class="pre">IndexInfo.get_aConstraint_iColumn()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.get_aConstraint_op"><code class="docutils literal notranslate"><span class="pre">IndexInfo.get_aConstraint_op()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.get_aConstraint_rhs"><code class="docutils literal notranslate"><span class="pre">IndexInfo.get_aConstraint_rhs()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.get_aConstraint_usable"><code class="docutils literal notranslate"><span class="pre">IndexInfo.get_aConstraint_usable()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.get_aOrderBy_desc"><code class="docutils literal notranslate"><span class="pre">IndexInfo.get_aOrderBy_desc()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.get_aOrderBy_iColumn"><code class="docutils literal notranslate"><span class="pre">IndexInfo.get_aOrderBy_iColumn()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.idxFlags"><code class="docutils literal notranslate"><span class="pre">IndexInfo.idxFlags</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.idxNum"><code class="docutils literal notranslate"><span class="pre">IndexInfo.idxNum</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.idxStr"><code class="docutils literal notranslate"><span class="pre">IndexInfo.idxStr</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.nConstraint"><code class="docutils literal notranslate"><span class="pre">IndexInfo.nConstraint</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.nOrderBy"><code class="docutils literal notranslate"><span class="pre">IndexInfo.nOrderBy</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.orderByConsumed"><code class="docutils literal notranslate"><span class="pre">IndexInfo.orderByConsumed</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.set_aConstraintUsage_argvIndex"><code class="docutils literal notranslate"><span class="pre">IndexInfo.set_aConstraintUsage_argvIndex()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.set_aConstraintUsage_in"><code class="docutils literal notranslate"><span class="pre">IndexInfo.set_aConstraintUsage_in()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.IndexInfo.set_aConstraintUsage_omit"><code class="docutils literal notranslate"><span class="pre">IndexInfo.set_aConstraintUsage_omit()</span></code></a></li>
</ul>
</li>
</ul>
</li>
<li class="toctree-l2"><a class="reference internal" href="#vtmodule-class">VTModule class</a><ul>
<li class="toctree-l3"><a class="reference internal" href="#apsw.VTModule"><code class="docutils literal notranslate"><span class="pre">VTModule</span></code></a><ul>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTModule.Connect"><code class="docutils literal notranslate"><span class="pre">VTModule.Connect()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTModule.Create"><code class="docutils literal notranslate"><span class="pre">VTModule.Create()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTModule.ShadowName"><code class="docutils literal notranslate"><span class="pre">VTModule.ShadowName()</span></code></a></li>
</ul>
</li>
</ul>
</li>
<li class="toctree-l2"><a class="reference internal" href="#vttable-class">VTTable class</a><ul>
<li class="toctree-l3"><a class="reference internal" href="#apsw.VTTable"><code class="docutils literal notranslate"><span class="pre">VTTable</span></code></a><ul>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.Begin"><code class="docutils literal notranslate"><span class="pre">VTTable.Begin()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.BestIndex"><code class="docutils literal notranslate"><span class="pre">VTTable.BestIndex()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.BestIndexObject"><code class="docutils literal notranslate"><span class="pre">VTTable.BestIndexObject()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.Commit"><code class="docutils literal notranslate"><span class="pre">VTTable.Commit()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.Destroy"><code class="docutils literal notranslate"><span class="pre">VTTable.Destroy()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.Disconnect"><code class="docutils literal notranslate"><span class="pre">VTTable.Disconnect()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.FindFunction"><code class="docutils literal notranslate"><span class="pre">VTTable.FindFunction()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.Integrity"><code class="docutils literal notranslate"><span class="pre">VTTable.Integrity()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.Open"><code class="docutils literal notranslate"><span class="pre">VTTable.Open()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.Release"><code class="docutils literal notranslate"><span class="pre">VTTable.Release()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.Rename"><code class="docutils literal notranslate"><span class="pre">VTTable.Rename()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.Rollback"><code class="docutils literal notranslate"><span class="pre">VTTable.Rollback()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.Savepoint"><code class="docutils literal notranslate"><span class="pre">VTTable.Savepoint()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.Sync"><code class="docutils literal notranslate"><span class="pre">VTTable.Sync()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.UpdateChangeRow"><code class="docutils literal notranslate"><span class="pre">VTTable.UpdateChangeRow()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.UpdateDeleteRow"><code class="docutils literal notranslate"><span class="pre">VTTable.UpdateDeleteRow()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTTable.UpdateInsertRow"><code class="docutils literal notranslate"><span class="pre">VTTable.UpdateInsertRow()</span></code></a></li>
</ul>
</li>
</ul>
</li>
<li class="toctree-l2"><a class="reference internal" href="#vtcursor-class">VTCursor class</a><ul>
<li class="toctree-l3"><a class="reference internal" href="#apsw.VTCursor"><code class="docutils literal notranslate"><span class="pre">VTCursor</span></code></a><ul>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTCursor.Close"><code class="docutils literal notranslate"><span class="pre">VTCursor.Close()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTCursor.Column"><code class="docutils literal notranslate"><span class="pre">VTCursor.Column()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTCursor.ColumnNoChange"><code class="docutils literal notranslate"><span class="pre">VTCursor.ColumnNoChange()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTCursor.Eof"><code class="docutils literal notranslate"><span class="pre">VTCursor.Eof()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTCursor.Filter"><code class="docutils literal notranslate"><span class="pre">VTCursor.Filter()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTCursor.Next"><code class="docutils literal notranslate"><span class="pre">VTCursor.Next()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#apsw.VTCursor.Rowid"><code class="docutils literal notranslate"><span class="pre">VTCursor.Rowid()</span></code></a></li>
</ul>
</li>
</ul>
</li>
</ul>
</li>
<li class="toctree-l1"><a class="reference internal" href="vfs.html">Virtual File System (VFS)</a></li>
<li class="toctree-l1"><a class="reference internal" href="shell.html">Shell</a></li>
<li class="toctree-l1"><a class="reference internal" href="bestpractice.html">Best Practice</a></li>
<li class="toctree-l1"><a class="reference internal" href="ext.html">Various interesting and useful bits of functionality</a></li>
<li class="toctree-l1"><a class="reference internal" href="exceptions.html">Exceptions and Errors</a></li>
<li class="toctree-l1"><a class="reference internal" href="execution.html">Execution and tracing</a></li>
<li class="toctree-l1"><a class="reference internal" href="dbapi.html">DBAPI notes</a></li>
<li class="toctree-l1"><a class="reference internal" href="pysqlite.html">sqlite3 module differences</a></li>
<li class="toctree-l1"><a class="reference internal" href="benchmarking.html">Benchmarking</a></li>
<li class="toctree-l1"><a class="reference internal" href="copyright.html">Copyright and License</a></li>
<li class="toctree-l1"><a class="reference internal" href="changes.html">Change History</a></li>
<li class="toctree-l1"><a class="reference internal" href="py-modindex.html">Module Index</a></li>
<li class="toctree-l1"><a class="reference internal" href="genindex.html">Index</a></li>
</ul>
</div>
</div>
</nav>
<section data-toggle="wy-nav-shift" class="wy-nav-content-wrap"><nav class="wy-nav-top" aria-label="Mobile navigation menu" >
<i data-toggle="wy-nav-top" class="fa fa-bars"></i>
<a href="index.html">APSW</a>
</nav>
<div class="wy-nav-content">
<div class="rst-content style-external-links">
<div role="navigation" aria-label="Page navigation">
<ul class="wy-breadcrumbs">
<li><a href="index.html" class="icon icon-home" aria-label="Home"></a></li>
<li class="breadcrumb-item active">Virtual Tables</li>
<li class="wy-breadcrumbs-aside">
<a href="_sources/vtable.rst.txt" rel="nofollow"> View page source</a>
</li>
</ul><div class="rst-breadcrumbs-buttons" role="navigation" aria-label="Sequential page navigation">
<a href="backup.html" class="btn btn-neutral float-left" title="Backup" accesskey="p"><span class="fa fa-arrow-circle-left" aria-hidden="true"></span> Previous</a>
<a href="vfs.html" class="btn btn-neutral float-right" title="Virtual File System (VFS)" accesskey="n">Next <span class="fa fa-arrow-circle-right" aria-hidden="true"></span></a>
</div>
<hr/>
</div>
<div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
<div itemprop="articleBody">
<section id="virtual-tables">
<span id="virtualtables"></span><h1>Virtual Tables<a class="headerlink" href="#virtual-tables" title="Link to this heading"></a></h1>
<p><a class="reference external" href="https://sqlite.org/vtab.html">Virtual Tables</a> let a developer
provide an underlying table implementations, while still presenting
a normal SQL interface to the user. The person writing SQL doesn’t
need to know or care that some of the tables come from elsewhere.</p>
<p>Some examples of how you might use this:</p>
<ul class="simple">
<li><p>Translating to/from information stored in other formats</p></li>
<li><p>Accessing the data remotely (eg you could make a table that backends into the cloud)</p></li>
<li><p>Dynamic information (eg currently running processes, files and directories, objects in your program)</p></li>
<li><p>There are other examples on the <a class="reference external" href="https://sqlite.org/vtab.html">SQLite page</a></p></li>
</ul>
<div class="admonition tip">
<p class="admonition-title">Tip</p>
<p>You’ll find initial development a lot quicker by using
<a class="reference internal" href="ext.html#apsw.ext.make_virtual_module" title="apsw.ext.make_virtual_module"><code class="xref py py-meth docutils literal notranslate"><span class="pre">apsw.ext.make_virtual_module()</span></code></a> which lets you
export a Python function as a virtual table, being
able to provide positional and keyword arguments as
part of your query.</p>
<p>See <a class="reference internal" href="example.html#example-virtual-tables"><span class="std std-ref">the example</span></a>.</p>
</div>
<p>To write a virtual table, you need to have 3 types of object. A
<a class="reference internal" href="#apsw.VTModule" title="apsw.VTModule"><code class="xref py py-class docutils literal notranslate"><span class="pre">module</span></code></a> providing the module, a <a class="reference internal" href="#apsw.VTTable" title="apsw.VTTable"><code class="xref py py-class docutils literal notranslate"><span class="pre">virtual</span> <span class="pre">table</span></code></a>,
and a <a class="reference internal" href="#apsw.VTCursor" title="apsw.VTCursor"><code class="xref py py-class docutils literal notranslate"><span class="pre">cursor</span></code></a> that moves through a table.</p>
<section id="indexinfo-class">
<h2>IndexInfo class<a class="headerlink" href="#indexinfo-class" title="Link to this heading"></a></h2>
<dl class="py class">
<dt class="sig sig-object py" id="apsw.IndexInfo">
<em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">apsw.</span></span><span class="sig-name descname"><span class="pre">IndexInfo</span></span><a class="headerlink" href="#apsw.IndexInfo" title="Link to this definition"></a></dt>
<dd><p>IndexInfo represents the <a class="reference external" href="https://www.sqlite.org/c3ref/index_info.html">sqlite3_index_info</a> and associated
methods used in the <a class="reference internal" href="#apsw.VTTable.BestIndexObject" title="apsw.VTTable.BestIndexObject"><code class="xref py py-meth docutils literal notranslate"><span class="pre">VTTable.BestIndexObject()</span></code></a> method.</p>
<p>Naming is identical to the C structure rather than Pythonic. You can
access members directly while needing to use get/set methods for array
members.</p>
<p>You will get <a class="reference external" href="https://docs.python.org/3/library/exceptions.html#ValueError" title="(in Python v3.12)"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> if you use the object outside of an
BestIndex method.</p>
<p><a class="reference internal" href="ext.html#apsw.ext.index_info_to_dict" title="apsw.ext.index_info_to_dict"><code class="xref py py-meth docutils literal notranslate"><span class="pre">apsw.ext.index_info_to_dict()</span></code></a> provides a convenient
representation of this object as a <a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#dict" title="(in Python v3.12)"><code class="xref py py-class docutils literal notranslate"><span class="pre">dict</span></code></a>.</p>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="apsw.IndexInfo.colUsed">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">colUsed</span></span><em class="property"><span class="p"><span class="pre">:</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#set" title="(in Python v3.12)"><span class="pre">set</span></a><span class="p"><span class="pre">[</span></span><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a><span class="p"><span class="pre">]</span></span></em><a class="headerlink" href="#apsw.IndexInfo.colUsed" title="Link to this definition"></a></dt>
<dd><p>(Read-only) Columns used by the statement. Note that a set is returned, not
the underlying integer.</p>
</dd></dl>
<dl class="py attribute" id="index-0">
<dt class="sig sig-object py" id="apsw.IndexInfo.distinct">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">distinct</span></span><em class="property"><span class="p"><span class="pre">:</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></em><a class="headerlink" href="#apsw.IndexInfo.distinct" title="Link to this definition"></a></dt>
<dd><p>(Read-only) How the query planner would like output ordered
if the query is using group by or distinct.</p>
<p>Calls: <a class="reference external" href="https://sqlite.org/c3ref/vtab_distinct.html">sqlite3_vtab_distinct</a></p>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="apsw.IndexInfo.estimatedCost">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">estimatedCost</span></span><em class="property"><span class="p"><span class="pre">:</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/functions.html#float" title="(in Python v3.12)"><span class="pre">float</span></a></em><a class="headerlink" href="#apsw.IndexInfo.estimatedCost" title="Link to this definition"></a></dt>
<dd><p>Estimated cost of using this index</p>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="apsw.IndexInfo.estimatedRows">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">estimatedRows</span></span><em class="property"><span class="p"><span class="pre">:</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></em><a class="headerlink" href="#apsw.IndexInfo.estimatedRows" title="Link to this definition"></a></dt>
<dd><p>Estimated number of rows returned</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.IndexInfo.get_aConstraintUsage_argvIndex">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">get_aConstraintUsage_argvIndex</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">which</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></span><a class="headerlink" href="#apsw.IndexInfo.get_aConstraintUsage_argvIndex" title="Link to this definition"></a></dt>
<dd><p>Returns <em>argvIndex</em> for <em>aConstraintUsage[which]</em></p>
</dd></dl>
<dl class="py method" id="index-1">
<dt class="sig sig-object py" id="apsw.IndexInfo.get_aConstraintUsage_in">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">get_aConstraintUsage_in</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">which</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/functions.html#bool" title="(in Python v3.12)"><span class="pre">bool</span></a></span></span><a class="headerlink" href="#apsw.IndexInfo.get_aConstraintUsage_in" title="Link to this definition"></a></dt>
<dd><p>Returns True if the constraint is <em>in</em> - eg column in (3, 7, 9)</p>
<p>Calls: <a class="reference external" href="https://sqlite.org/c3ref/vtab_in.html">sqlite3_vtab_in</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.IndexInfo.get_aConstraintUsage_omit">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">get_aConstraintUsage_omit</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">which</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/functions.html#bool" title="(in Python v3.12)"><span class="pre">bool</span></a></span></span><a class="headerlink" href="#apsw.IndexInfo.get_aConstraintUsage_omit" title="Link to this definition"></a></dt>
<dd><p>Returns <em>omit</em> for <em>aConstraintUsage[which]</em></p>
</dd></dl>
<dl class="py method" id="index-2">
<dt class="sig sig-object py" id="apsw.IndexInfo.get_aConstraint_collation">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">get_aConstraint_collation</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">which</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a></span></span><a class="headerlink" href="#apsw.IndexInfo.get_aConstraint_collation" title="Link to this definition"></a></dt>
<dd><p>Returns collation name for <em>aConstraint[which]</em></p>
<p>Calls: <a class="reference external" href="https://sqlite.org/c3ref/vtab_collation.html">sqlite3_vtab_collation</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.IndexInfo.get_aConstraint_iColumn">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">get_aConstraint_iColumn</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">which</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></span><a class="headerlink" href="#apsw.IndexInfo.get_aConstraint_iColumn" title="Link to this definition"></a></dt>
<dd><p>Returns <em>iColumn</em> for <em>aConstraint[which]</em></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.IndexInfo.get_aConstraint_op">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">get_aConstraint_op</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">which</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></span><a class="headerlink" href="#apsw.IndexInfo.get_aConstraint_op" title="Link to this definition"></a></dt>
<dd><p>Returns <em>op</em> for <em>aConstraint[which]</em></p>
</dd></dl>
<dl class="py method" id="index-3">
<dt class="sig sig-object py" id="apsw.IndexInfo.get_aConstraint_rhs">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">get_aConstraint_rhs</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">which</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference internal" href="apsw.html#apsw.SQLiteValue" title="apsw.SQLiteValue"><span class="pre">SQLiteValue</span></a></span></span><a class="headerlink" href="#apsw.IndexInfo.get_aConstraint_rhs" title="Link to this definition"></a></dt>
<dd><p>Returns right hand side value if known, else None.</p>
<p>Calls: <a class="reference external" href="https://sqlite.org/c3ref/vtab_rhs_value.html">sqlite3_vtab_rhs_value</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.IndexInfo.get_aConstraint_usable">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">get_aConstraint_usable</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">which</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/functions.html#bool" title="(in Python v3.12)"><span class="pre">bool</span></a></span></span><a class="headerlink" href="#apsw.IndexInfo.get_aConstraint_usable" title="Link to this definition"></a></dt>
<dd><p>Returns <em>usable</em> for <em>aConstraint[which]</em></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.IndexInfo.get_aOrderBy_desc">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">get_aOrderBy_desc</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">which</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/functions.html#bool" title="(in Python v3.12)"><span class="pre">bool</span></a></span></span><a class="headerlink" href="#apsw.IndexInfo.get_aOrderBy_desc" title="Link to this definition"></a></dt>
<dd><p>Returns <em>desc</em> for <em>aOrderBy[which]</em></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.IndexInfo.get_aOrderBy_iColumn">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">get_aOrderBy_iColumn</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">which</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></span><a class="headerlink" href="#apsw.IndexInfo.get_aOrderBy_iColumn" title="Link to this definition"></a></dt>
<dd><p>Returns <em>iColumn</em> for <em>aOrderBy[which]</em></p>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="apsw.IndexInfo.idxFlags">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">idxFlags</span></span><em class="property"><span class="p"><span class="pre">:</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></em><a class="headerlink" href="#apsw.IndexInfo.idxFlags" title="Link to this definition"></a></dt>
<dd><p>Mask of <a class="reference internal" href="apsw.html#apsw.mapping_virtual_table_scan_flags" title="apsw.mapping_virtual_table_scan_flags"><code class="xref py py-attr docutils literal notranslate"><span class="pre">SQLITE_INDEX_SCAN</span> <span class="pre">flags</span></code></a></p>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="apsw.IndexInfo.idxNum">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">idxNum</span></span><em class="property"><span class="p"><span class="pre">:</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></em><a class="headerlink" href="#apsw.IndexInfo.idxNum" title="Link to this definition"></a></dt>
<dd><p>Number used to identify the index</p>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="apsw.IndexInfo.idxStr">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">idxStr</span></span><em class="property"><span class="p"><span class="pre">:</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a><span class="w"> </span><span class="p"><span class="pre">|</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></em><a class="headerlink" href="#apsw.IndexInfo.idxStr" title="Link to this definition"></a></dt>
<dd><p>Name used to identify the index</p>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="apsw.IndexInfo.nConstraint">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">nConstraint</span></span><em class="property"><span class="p"><span class="pre">:</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></em><a class="headerlink" href="#apsw.IndexInfo.nConstraint" title="Link to this definition"></a></dt>
<dd><p>(Read-only) Number of constraint entries</p>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="apsw.IndexInfo.nOrderBy">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">nOrderBy</span></span><em class="property"><span class="p"><span class="pre">:</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></em><a class="headerlink" href="#apsw.IndexInfo.nOrderBy" title="Link to this definition"></a></dt>
<dd><p>(Read-only) Number of order by entries</p>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="apsw.IndexInfo.orderByConsumed">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">orderByConsumed</span></span><em class="property"><span class="p"><span class="pre">:</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/functions.html#bool" title="(in Python v3.12)"><span class="pre">bool</span></a></em><a class="headerlink" href="#apsw.IndexInfo.orderByConsumed" title="Link to this definition"></a></dt>
<dd><p>True if index output is already ordered</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.IndexInfo.set_aConstraintUsage_argvIndex">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">set_aConstraintUsage_argvIndex</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">which</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">argvIndex</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.IndexInfo.set_aConstraintUsage_argvIndex" title="Link to this definition"></a></dt>
<dd><p>Sets <em>argvIndex</em> for <em>aConstraintUsage[which]</em></p>
</dd></dl>
<dl class="py method" id="index-4">
<dt class="sig sig-object py" id="apsw.IndexInfo.set_aConstraintUsage_in">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">set_aConstraintUsage_in</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">which</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">filter_all</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#bool" title="(in Python v3.12)"><span class="pre">bool</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.IndexInfo.set_aConstraintUsage_in" title="Link to this definition"></a></dt>
<dd><p>If <em>which</em> is an <em>in</em> constraint, and <em>filter_all</em> is True then your <a class="reference internal" href="#apsw.VTCursor.Filter" title="apsw.VTCursor.Filter"><code class="xref py py-meth docutils literal notranslate"><span class="pre">VTCursor.Filter()</span></code></a>
method will have all of the values at once.</p>
<p>Calls: <a class="reference external" href="https://sqlite.org/c3ref/vtab_in.html">sqlite3_vtab_in</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.IndexInfo.set_aConstraintUsage_omit">
<span class="sig-prename descclassname"><span class="pre">IndexInfo.</span></span><span class="sig-name descname"><span class="pre">set_aConstraintUsage_omit</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">which</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">omit</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#bool" title="(in Python v3.12)"><span class="pre">bool</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.IndexInfo.set_aConstraintUsage_omit" title="Link to this definition"></a></dt>
<dd><p>Sets <em>omit</em> for <em>aConstraintUsage[which]</em></p>
</dd></dl>
</section>
<section id="vtmodule-class">
<h2>VTModule class<a class="headerlink" href="#vtmodule-class" title="Link to this heading"></a></h2>
<dl class="py class">
<dt class="sig sig-object py" id="apsw.VTModule">
<em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">apsw.</span></span><span class="sig-name descname"><span class="pre">VTModule</span></span><a class="headerlink" href="#apsw.VTModule" title="Link to this definition"></a></dt>
<dd></dd></dl>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>There is no actual <em>VTModule</em> class - it is shown this way for
documentation convenience and is present as a <a class="reference external" href="https://docs.python.org/3/library/typing.html#typing.Protocol">typing protocol</a>.</p>
</div>
<p>A module instance is used to create the virtual tables. Once you have
a module object, you register it with a connection by calling
<a class="reference internal" href="connection.html#apsw.Connection.create_module" title="apsw.Connection.create_module"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Connection.create_module()</span></code></a>:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="c1"># make an instance</span>
<span class="n">mymod</span><span class="o">=</span><span class="n">MyModuleClass</span><span class="p">()</span>
<span class="c1"># register the vtable on connection con</span>
<span class="n">con</span><span class="o">.</span><span class="n">create_module</span><span class="p">(</span><span class="s2">"modulename"</span><span class="p">,</span> <span class="n">mymod</span><span class="p">)</span>
<span class="c1"># tell SQLite about the table</span>
<span class="n">con</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s2">"create VIRTUAL table tablename USING modulename('arg1', 2)"</span><span class="p">)</span>
</pre></div>
</div>
<p>The create step is to tell SQLite about the existence of the table.
Any number of tables referring to the same module can be made this
way.</p>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTModule.Connect">
<span class="sig-prename descclassname"><span class="pre">VTModule.</span></span><span class="sig-name descname"><span class="pre">Connect</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">connection</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="connection.html#apsw.Connection" title="apsw.Connection"><span class="pre">Connection</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">modulename</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">databasename</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">tablename</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a></span></em>, <em class="sig-param"><span class="o"><span class="pre">*</span></span><span class="n"><span class="pre">args</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#tuple" title="(in Python v3.12)"><span class="pre">tuple</span></a><span class="p"><span class="pre">[</span></span><a class="reference internal" href="apsw.html#apsw.SQLiteValue" title="apsw.SQLiteValue"><span class="pre">SQLiteValue</span></a><span class="p"><span class="pre">,</span></span><span class="w"> </span><span class="p"><span class="pre">...</span></span><span class="p"><span class="pre">]</span></span></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#tuple" title="(in Python v3.12)"><span class="pre">tuple</span></a><span class="p"><span class="pre">[</span></span><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a><span class="p"><span class="pre">,</span></span><span class="w"> </span><a class="reference internal" href="#apsw.VTTable" title="apsw.VTTable"><span class="pre">VTTable</span></a><span class="p"><span class="pre">]</span></span></span></span><a class="headerlink" href="#apsw.VTModule.Connect" title="Link to this definition"></a></dt>
<dd><p>The parameters and return are identical to
<a class="reference internal" href="#apsw.VTModule.Create" title="apsw.VTModule.Create"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Create()</span></code></a>. This method is called
when there are additional references to the table. <a class="reference internal" href="#apsw.VTModule.Create" title="apsw.VTModule.Create"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Create()</span></code></a> will be called the first time and
<a class="reference internal" href="#apsw.VTModule.Connect" title="apsw.VTModule.Connect"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Connect()</span></code></a> after that.</p>
<p>The advise is to create caches, generated data and other
heavyweight processing on <a class="reference internal" href="#apsw.VTModule.Create" title="apsw.VTModule.Create"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Create()</span></code></a> calls and then
find and reuse that on the subsequent <a class="reference internal" href="#apsw.VTModule.Connect" title="apsw.VTModule.Connect"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Connect()</span></code></a>
calls.</p>
<p>The corresponding call is <a class="reference internal" href="#apsw.VTTable.Disconnect" title="apsw.VTTable.Disconnect"><code class="xref py py-meth docutils literal notranslate"><span class="pre">VTTable.Disconnect()</span></code></a>. If you have a simple virtual table implementation, then just
set <a class="reference internal" href="#apsw.VTModule.Connect" title="apsw.VTModule.Connect"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Connect()</span></code></a> to be the same as <a class="reference internal" href="#apsw.VTModule.Create" title="apsw.VTModule.Create"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Create()</span></code></a>:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">MyModule</span><span class="p">:</span>
<span class="k">def</span> <span class="nf">Create</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">connection</span><span class="p">,</span> <span class="n">modulename</span><span class="p">,</span> <span class="n">databasename</span><span class="p">,</span> <span class="n">tablename</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">):</span>
<span class="c1"># do lots of hard work</span>
<span class="n">Connect</span><span class="o">=</span><span class="n">Create</span>
</pre></div>
</div>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xconnect_method">SQLite xConnect reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTModule.Create">
<span class="sig-prename descclassname"><span class="pre">VTModule.</span></span><span class="sig-name descname"><span class="pre">Create</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">connection</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="connection.html#apsw.Connection" title="apsw.Connection"><span class="pre">Connection</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">modulename</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">databasename</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">tablename</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a></span></em>, <em class="sig-param"><span class="o"><span class="pre">*</span></span><span class="n"><span class="pre">args</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#tuple" title="(in Python v3.12)"><span class="pre">tuple</span></a><span class="p"><span class="pre">[</span></span><a class="reference internal" href="apsw.html#apsw.SQLiteValue" title="apsw.SQLiteValue"><span class="pre">SQLiteValue</span></a><span class="p"><span class="pre">,</span></span><span class="w"> </span><span class="p"><span class="pre">...</span></span><span class="p"><span class="pre">]</span></span></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#tuple" title="(in Python v3.12)"><span class="pre">tuple</span></a><span class="p"><span class="pre">[</span></span><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a><span class="p"><span class="pre">,</span></span><span class="w"> </span><a class="reference internal" href="#apsw.VTTable" title="apsw.VTTable"><span class="pre">VTTable</span></a><span class="p"><span class="pre">]</span></span></span></span><a class="headerlink" href="#apsw.VTModule.Create" title="Link to this definition"></a></dt>
<dd><p>Called when a table is first created on a <a class="reference internal" href="connection.html#apsw.Connection" title="apsw.Connection"><code class="xref py py-class docutils literal notranslate"><span class="pre">connection</span></code></a>.</p>
<dl class="field-list simple">
<dt class="field-odd">Parameters<span class="colon">:</span></dt>
<dd class="field-odd"><ul class="simple">
<li><p><strong>connection</strong> – An instance of <a class="reference internal" href="connection.html#apsw.Connection" title="apsw.Connection"><code class="xref py py-class docutils literal notranslate"><span class="pre">Connection</span></code></a></p></li>
<li><p><strong>modulename</strong> – The string name under which the module was <a class="reference internal" href="connection.html#apsw.Connection.create_module" title="apsw.Connection.create_module"><code class="xref py py-meth docutils literal notranslate"><span class="pre">registered</span></code></a></p></li>
<li><p><strong>databasename</strong> – The name of the database. <cite>main</cite>, <cite>temp</cite>, the name in <a class="reference external" href="https://sqlite.org/lang_attach.html">ATTACH</a></p></li>
<li><p><strong>tablename</strong> – Name of the table the user wants to create.</p></li>
<li><p><strong>args</strong> – Any arguments that were specified in the <a class="reference external" href="https://sqlite.org/lang_createvtab.html">create virtual table</a> statement.</p></li>
</ul>
</dd>
<dt class="field-even">Returns<span class="colon">:</span></dt>
<dd class="field-even"><p>A list of two items. The first is a SQL <a class="reference external" href="https://sqlite.org/lang_createtable.html">create table</a> statement. The
columns are parsed so that SQLite knows what columns and declared types exist for the table. The second item
is an object that implements the <a class="reference internal" href="#apsw.VTTable" title="apsw.VTTable"><code class="xref py py-class docutils literal notranslate"><span class="pre">table</span></code></a> methods.</p>
</dd>
</dl>
<p>The corresponding call is <a class="reference internal" href="#apsw.VTTable.Destroy" title="apsw.VTTable.Destroy"><code class="xref py py-meth docutils literal notranslate"><span class="pre">VTTable.Destroy()</span></code></a>.</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xcreate_method">SQLite xCreate reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTModule.ShadowName">
<span class="sig-prename descclassname"><span class="pre">VTModule.</span></span><span class="sig-name descname"><span class="pre">ShadowName</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">table_suffix</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/functions.html#bool" title="(in Python v3.12)"><span class="pre">bool</span></a></span></span><a class="headerlink" href="#apsw.VTModule.ShadowName" title="Link to this definition"></a></dt>
<dd><p>This method is called to check if
<em>table_suffix</em> is a <a class="reference external" href="https://www.sqlite.org/vtab.html#the_xshadowname_method">shadow name</a></p>
<p>The default implementation always returns <em>False</em>.</p>
<p>If a virtual table is created using this module
named <code class="code docutils literal notranslate"><span class="pre">example</span></code> and then a real table is created
named <code class="code docutils literal notranslate"><span class="pre">example_content</span></code>, this would be called with
a <em>table_suffix</em> of <code class="code docutils literal notranslate"><span class="pre">content</span></code></p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xshadowname_method">SQLite xShadowName reference</a></p>
</dd></dl>
</section>
<section id="vttable-class">
<h2>VTTable class<a class="headerlink" href="#vttable-class" title="Link to this heading"></a></h2>
<dl class="py class">
<dt class="sig sig-object py" id="apsw.VTTable">
<em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">apsw.</span></span><span class="sig-name descname"><span class="pre">VTTable</span></span><a class="headerlink" href="#apsw.VTTable" title="Link to this definition"></a></dt>
<dd><div class="admonition note">
<p class="admonition-title">Note</p>
<p>There is no actual <em>VTTable</em> class - it is shown this way for
documentation convenience and is present as a <a class="reference external" href="https://docs.python.org/3/library/typing.html#typing.Protocol">typing protocol</a>.</p>
</div>
<p>The <a class="reference internal" href="#apsw.VTTable" title="apsw.VTTable"><code class="xref py py-class docutils literal notranslate"><span class="pre">VTTable</span></code></a> object contains knowledge of the indices, makes
cursors and can perform transactions.</p>
<p>A virtual table is structured as a series of rows, each of which has
the same number of columns. The value in a column must be one of the <a class="reference external" href="https://sqlite.org/datatype3.html">5
supported types</a>, but the
type can be different between rows for the same column. The virtual
table routines identify the columns by number, starting at zero.</p>
<p>Each row has a <strong>unique</strong> 64 bit integer <a class="reference external" href="https://sqlite.org/autoinc.html">rowid</a> with the <a class="reference internal" href="#apsw.VTCursor" title="apsw.VTCursor"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cursor</span></code></a> routines operating on this number, as well as some of
the <a class="reference internal" href="#apsw.VTTable" title="apsw.VTTable"><code class="xref py py-class docutils literal notranslate"><span class="pre">Table</span></code></a> routines such as <a class="reference internal" href="#apsw.VTTable.UpdateChangeRow" title="apsw.VTTable.UpdateChangeRow"><code class="xref py py-meth docutils literal notranslate"><span class="pre">UpdateChangeRow</span></code></a>.</p>
<p>It is possible to <a class="reference external" href="https://www.sqlite.org/vtab.html#_without_rowid_virtual_tables_">not have a rowid</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.Begin">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">Begin</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.VTTable.Begin" title="Link to this definition"></a></dt>
<dd><p>This function is used as part of transactions. You do not have to
provide the method.</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xbegin_method">SQLite xBegin reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.BestIndex">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">BestIndex</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">constraints</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><span class="pre">Sequence</span><span class="p"><span class="pre">[</span></span><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#tuple" title="(in Python v3.12)"><span class="pre">tuple</span></a><span class="p"><span class="pre">[</span></span><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a><span class="p"><span class="pre">,</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a><span class="p"><span class="pre">]</span></span><span class="p"><span class="pre">]</span></span></span></em>, <em class="sig-param"><span class="n"><span class="pre">orderbys</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><span class="pre">Sequence</span><span class="p"><span class="pre">[</span></span><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#tuple" title="(in Python v3.12)"><span class="pre">tuple</span></a><span class="p"><span class="pre">[</span></span><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a><span class="p"><span class="pre">,</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a><span class="p"><span class="pre">]</span></span><span class="p"><span class="pre">]</span></span></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><span class="pre">Any</span></span></span><a class="headerlink" href="#apsw.VTTable.BestIndex" title="Link to this definition"></a></dt>
<dd><p>This is a complex method. To get going initially, just return
<em>None</em> and you will be fine. You should also consider using
<a class="reference internal" href="#apsw.VTTable.BestIndexObject" title="apsw.VTTable.BestIndexObject"><code class="xref py py-meth docutils literal notranslate"><span class="pre">BestIndexObject()</span></code></a> instead.</p>
<p>Implementing this method reduces the number of rows scanned
in your table to satisfy queries, but only if you have an
index or index like mechanism available.</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>The implementation of this method differs slightly from the
<a class="reference external" href="https://sqlite.org/vtab.html">SQLite documentation</a>
for the C API. You are not passed “unusable” constraints. The
argv/constraintarg positions are not off by one. In the C api, you
have to return position 1 to get something passed to
<a class="reference internal" href="#apsw.VTCursor.Filter" title="apsw.VTCursor.Filter"><code class="xref py py-meth docutils literal notranslate"><span class="pre">VTCursor.Filter()</span></code></a> in position 0. With the APSW
implementation, you return position 0 to get Filter arg 0,
position 1 to get Filter arg 1 etc.</p>
</div>
<p>The purpose of this method is to ask if you have the ability to
determine if a row meets certain constraints that doesn’t involve
visiting every row. An example constraint is <code class="docutils literal notranslate"><span class="pre">price</span> <span class="pre">></span> <span class="pre">74.99</span></code>. In a
traditional SQL database, queries with constraints can be speeded up
<a class="reference external" href="https://sqlite.org/lang_createindex.html">with indices</a>. If
you return None, then SQLite will visit every row in your table and
evaluate the constraints itself. Your index choice returned from
BestIndex will also be passed to the <a class="reference internal" href="#apsw.VTCursor.Filter" title="apsw.VTCursor.Filter"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Filter()</span></code></a> method on your cursor
object. Note that SQLite may call this method multiple times trying
to find the most efficient way of answering a complex query.</p>
<p><strong>constraints</strong></p>
<p>You will be passed the constraints as a sequence of tuples containing two
items. The first item is the column number and the second item is
the operation.</p>
<blockquote>
<div><p>Example query: <code class="docutils literal notranslate"><span class="pre">select</span> <span class="pre">*</span> <span class="pre">from</span> <span class="pre">foo</span> <span class="pre">where</span> <span class="pre">price</span> <span class="pre">></span> <span class="pre">74.99</span> <span class="pre">and</span>
<span class="pre">quantity<=10</span> <span class="pre">and</span> <span class="pre">customer='Acme</span> <span class="pre">Widgets'</span></code></p>
<p>If customer is column 0, price column 2 and quantity column 5
then the constraints will be:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="n">apsw</span><span class="o">.</span><span class="n">SQLITE_INDEX_CONSTRAINT_GT</span><span class="p">),</span>
<span class="p">(</span><span class="mi">5</span><span class="p">,</span> <span class="n">apsw</span><span class="o">.</span><span class="n">SQLITE_INDEX_CONSTRAINT_LE</span><span class="p">),</span>
<span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="n">apsw</span><span class="o">.</span><span class="n">SQLITE_INDEX_CONSTRAINT_EQ</span><span class="p">)</span>
</pre></div>
</div>
<p>Note that you do not get the value of the constraint (ie “Acme
Widgets”, 74.99 and 10 in this example).</p>
</div></blockquote>
<p>If you do have any suitable indices then you return a sequence the
same length as constraints with the members mapping to the
constraints in order. Each can be one of None, an integer or a tuple
of an integer and a boolean. Conceptually SQLite is giving you a
list of constraints and you are returning a list of the same length
describing how you could satisfy each one.</p>
<p>Each list item returned corresponding to a constraint is one of:</p>
<blockquote>
<div><dl class="simple">
<dt>None</dt><dd><p>This means you have no index for that constraint. SQLite
will have to iterate over every row for it.</p>
</dd>
<dt>integer</dt><dd><p>This is the argument number for the constraintargs being passed
into the <a class="reference internal" href="#apsw.VTCursor.Filter" title="apsw.VTCursor.Filter"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Filter()</span></code></a> function of your
<a class="reference internal" href="#apsw.VTCursor" title="apsw.VTCursor"><code class="xref py py-class docutils literal notranslate"><span class="pre">cursor</span></code></a> (the values “Acme Widgets”, 74.99
and 10 in the example).</p>
</dd>
<dt>(integer, boolean)</dt><dd><p>By default SQLite will check what you return. For example if
you said that you had an index on price and so would only
return rows greater than 74.99, then SQLite will still
check that each row you returned is greater than 74.99.
If the boolean is True then SQLite will not double
check, while False retains the default double checking.</p>
</dd>
</dl>
</div></blockquote>
<p>Example query: <code class="docutils literal notranslate"><span class="pre">select</span> <span class="pre">*</span> <span class="pre">from</span> <span class="pre">foo</span> <span class="pre">where</span> <span class="pre">price</span> <span class="pre">></span> <span class="pre">74.99</span> <span class="pre">and</span>
<span class="pre">quantity<=10</span> <span class="pre">and</span> <span class="pre">customer=='Acme</span> <span class="pre">Widgets'</span></code>. customer is column 0,
price column 2 and quantity column 5. You can index on customer
equality and price.</p>
<table class="docutils align-default">
<thead>
<tr class="row-odd"><th class="head"><p>Constraints (in)</p></th>
<th class="head"><p>Constraints used (out)</p></th>
</tr>
</thead>
<tbody>
<tr class="row-even"><td><div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="n">apsw</span><span class="o">.</span><span class="n">SQLITE_INDEX_CONSTRAINT_GT</span><span class="p">),</span>
<span class="p">(</span><span class="mi">5</span><span class="p">,</span> <span class="n">apsw</span><span class="o">.</span><span class="n">SQLITE_INDEX_CONSTRAINT_LE</span><span class="p">),</span>
<span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="n">apsw</span><span class="o">.</span><span class="n">SQLITE_INDEX_CONSTRAINT_EQ</span><span class="p">)</span>
</pre></div>
</div>
</td>
<td><div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="mi">1</span><span class="p">,</span>
<span class="kc">None</span><span class="p">,</span>
<span class="mi">0</span>
</pre></div>
</div>
</td>
</tr>
</tbody>
</table>
<p>When your <a class="reference internal" href="#apsw.VTCursor.Filter" title="apsw.VTCursor.Filter"><code class="xref py py-class docutils literal notranslate"><span class="pre">Filter</span></code></a> method in the cursor is called,
constraintarg[0] will be “Acme Widgets” (customer constraint value)
and constraintarg[1] will be 74.99 (price constraint value). You can
also return an index number (integer) and index string to use
(SQLite attaches no significance to these values - they are passed
as is to your <a class="reference internal" href="#apsw.VTCursor.Filter" title="apsw.VTCursor.Filter"><code class="xref py py-meth docutils literal notranslate"><span class="pre">VTCursor.Filter()</span></code></a> method as a way for the
BestIndex method to let the <a class="reference internal" href="#apsw.VTCursor.Filter" title="apsw.VTCursor.Filter"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Filter()</span></code></a> method know
which of your indices or similar mechanism to use.</p>
<p><strong>orderbys</strong></p>
<p>The second argument to BestIndex is a sequence of orderbys because
the query requested the results in a certain order. If your data is
already in that order then SQLite can give the results back as
is. If not, then SQLite will have to sort the results first.</p>
<blockquote>
<div><p>Example query: <code class="docutils literal notranslate"><span class="pre">select</span> <span class="pre">*</span> <span class="pre">from</span> <span class="pre">foo</span> <span class="pre">order</span> <span class="pre">by</span> <span class="pre">price</span> <span class="pre">desc,</span> <span class="pre">quantity</span> <span class="pre">asc</span></code></p>
<p>Price is column 2, quantity column 5 so orderbys will be:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="kc">True</span><span class="p">),</span> <span class="c1"># True means descending, False is ascending</span>
<span class="p">(</span><span class="mi">5</span><span class="p">,</span> <span class="kc">False</span><span class="p">)</span>
</pre></div>
</div>
</div></blockquote>
<p><strong>Return</strong></p>
<p>You should return up to 5 items. Items not present in the return have a default value.</p>
<dl class="simple">
<dt>0: constraints used (default None)</dt><dd><p>This must either be None or a sequence the same length as
constraints passed in. Each item should be as specified above
saying if that constraint is used, and if so which constraintarg
to make the value be in your <a class="reference internal" href="#apsw.VTCursor.Filter" title="apsw.VTCursor.Filter"><code class="xref py py-meth docutils literal notranslate"><span class="pre">VTCursor.Filter()</span></code></a> function.</p>
</dd>
<dt>1: index number (default zero)</dt><dd><p>This value is passed as is to <a class="reference internal" href="#apsw.VTCursor.Filter" title="apsw.VTCursor.Filter"><code class="xref py py-meth docutils literal notranslate"><span class="pre">VTCursor.Filter()</span></code></a></p>
</dd>
<dt>2: index string (default None)</dt><dd><p>This value is passed as is to <a class="reference internal" href="#apsw.VTCursor.Filter" title="apsw.VTCursor.Filter"><code class="xref py py-meth docutils literal notranslate"><span class="pre">VTCursor.Filter()</span></code></a></p>
</dd>
<dt>3: orderby consumed (default False)</dt><dd><p>Return True if your output will be in exactly the same order as the orderbys passed in</p>
</dd>
<dt>4: estimated cost (default a huge number)</dt><dd><p>Approximately how many disk operations are needed to provide the
results. SQLite uses the cost to optimise queries. For example if
the query includes <em>A or B</em> and A has 2,000 operations and B has 100
then it is best to evaluate B before A.</p>
</dd>
</dl>
<p><strong>A complete example</strong></p>
<p>Query is <code class="docutils literal notranslate"><span class="pre">select</span> <span class="pre">*</span> <span class="pre">from</span> <span class="pre">foo</span> <span class="pre">where</span> <span class="pre">price>74.99</span> <span class="pre">and</span> <span class="pre">quantity<=10</span> <span class="pre">and</span>
<span class="pre">customer=="Acme</span> <span class="pre">Widgets"</span> <span class="pre">order</span> <span class="pre">by</span> <span class="pre">price</span> <span class="pre">desc,</span> <span class="pre">quantity</span> <span class="pre">asc</span></code>.
Customer is column 0, price column 2 and quantity column 5. You can
index on customer equality and price.</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">BestIndex</span><span class="p">(</span><span class="n">constraints</span><span class="p">,</span> <span class="n">orderbys</span><span class="p">)</span>
<span class="n">constraints</span><span class="o">=</span> <span class="p">(</span> <span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="n">apsw</span><span class="o">.</span><span class="n">SQLITE_INDEX_CONSTRAINT_GT</span><span class="p">),</span>
<span class="p">(</span><span class="mi">5</span><span class="p">,</span> <span class="n">apsw</span><span class="o">.</span><span class="n">SQLITE_INDEX_CONSTRAINT_LE</span><span class="p">),</span>
<span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="n">apsw</span><span class="o">.</span><span class="n">SQLITE_INDEX_CONSTRAINT_EQ</span><span class="p">)</span> <span class="p">)</span>
<span class="n">orderbys</span><span class="o">=</span> <span class="p">(</span> <span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="kc">True</span><span class="p">),</span> <span class="p">(</span><span class="mi">5</span><span class="p">,</span> <span class="kc">False</span><span class="p">)</span> <span class="p">)</span>
<span class="c1"># You return</span>
<span class="p">(</span> <span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="kc">None</span><span class="p">,</span> <span class="mi">0</span><span class="p">),</span> <span class="c1"># constraints used</span>
<span class="mi">27</span><span class="p">,</span> <span class="c1"># index number</span>
<span class="s2">"idx_pr_cust"</span><span class="p">,</span> <span class="c1"># index name</span>
<span class="kc">False</span><span class="p">,</span> <span class="c1"># results are not in orderbys order</span>
<span class="mi">1000</span> <span class="c1"># about 1000 disk operations to access index</span>
<span class="p">)</span>
<span class="c1"># Your Cursor.Filter method will be called with:</span>
<span class="mi">27</span><span class="p">,</span> <span class="c1"># index number you returned</span>
<span class="s2">"idx_pr_cust"</span><span class="p">,</span> <span class="c1"># index name you returned</span>
<span class="s2">"Acme Widgets"</span><span class="p">,</span> <span class="c1"># constraintarg[0] - customer</span>
<span class="mf">74.99</span> <span class="c1"># constraintarg[1] - price</span>
</pre></div>
</div>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xbestindex_method">SQLite xBestIndex reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.BestIndexObject">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">BestIndexObject</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">index_info</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="#apsw.IndexInfo" title="apsw.IndexInfo"><span class="pre">IndexInfo</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/functions.html#bool" title="(in Python v3.12)"><span class="pre">bool</span></a></span></span><a class="headerlink" href="#apsw.VTTable.BestIndexObject" title="Link to this definition"></a></dt>
<dd><p>This method is called instead of <a class="reference internal" href="#apsw.VTTable.BestIndex" title="apsw.VTTable.BestIndex"><code class="xref py py-meth docutils literal notranslate"><span class="pre">BestIndex()</span></code></a> if
<em>use_bestindex_object</em> was <em>True</em> in the call to
<a class="reference internal" href="connection.html#apsw.Connection.create_module" title="apsw.Connection.create_module"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Connection.create_module()</span></code></a>.</p>
<p>Use the <a class="reference internal" href="#apsw.IndexInfo" title="apsw.IndexInfo"><code class="xref py py-class docutils literal notranslate"><span class="pre">IndexInfo</span></code></a> to tell SQLite about your indexes, and
extract other information.</p>
<p>Return <em>True</em> to indicate all is well. If you return <em>False</em> or there is an error,
then <a class="reference external" href="https://www.sqlite.org/vtab.html#return_value">SQLITE_CONSTRAINT</a> is returned to
SQLite.</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xbestindex_method">SQLite xBestIndex reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.Commit">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">Commit</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.VTTable.Commit" title="Link to this definition"></a></dt>
<dd><p>This function is used as part of transactions. You do not have to
provide the method.</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xcommit_method">SQLite xCommit reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.Destroy">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">Destroy</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.VTTable.Destroy" title="Link to this definition"></a></dt>
<dd><p>The opposite of <a class="reference internal" href="#apsw.VTModule.Create" title="apsw.VTModule.Create"><code class="xref py py-meth docutils literal notranslate"><span class="pre">VTModule.Create()</span></code></a>. This method is called when
the table is no longer used. Note that you must always release
resources even if you intend to return an error, as it will not be
called again on error.</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xdestroy_method">SQLite xDestroy reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.Disconnect">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">Disconnect</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.VTTable.Disconnect" title="Link to this definition"></a></dt>
<dd><p>The opposite of <a class="reference internal" href="#apsw.VTModule.Connect" title="apsw.VTModule.Connect"><code class="xref py py-meth docutils literal notranslate"><span class="pre">VTModule.Connect()</span></code></a>. This method is called when
a reference to a virtual table is no longer used, but <a class="reference internal" href="#apsw.VTTable.Destroy" title="apsw.VTTable.Destroy"><code class="xref py py-meth docutils literal notranslate"><span class="pre">VTTable.Destroy()</span></code></a> will
be called when the table is no longer used.</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xdisconnect_method">SQLite xDisconnect reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.FindFunction">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">FindFunction</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">name</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">nargs</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a><span class="w"> </span><span class="p"><span class="pre">|</span></span><span class="w"> </span><span class="pre">Callable</span><span class="w"> </span><span class="p"><span class="pre">|</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#tuple" title="(in Python v3.12)"><span class="pre">tuple</span></a><span class="p"><span class="pre">[</span></span><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a><span class="p"><span class="pre">,</span></span><span class="w"> </span><span class="pre">Callable</span><span class="p"><span class="pre">]</span></span></span></span><a class="headerlink" href="#apsw.VTTable.FindFunction" title="Link to this definition"></a></dt>
<dd><p>Called to find if the virtual table has its own implementation of a
particular scalar function. You do not have to provide this method.</p>
<dl class="field-list simple">
<dt class="field-odd">Parameters<span class="colon">:</span></dt>
<dd class="field-odd"><ul class="simple">
<li><p><strong>name</strong> – The function name</p></li>
<li><p><strong>nargs</strong> – How many arguments the function takes</p></li>
</ul>
</dd>
</dl>
<p>Return <em>None</em> if you don’t have the function. Zero is then returned to SQLite.</p>
<p>Return a callable if you have one. One is then returned to SQLite with the function.</p>
<p>Return a sequence of int, callable. The int is returned to SQLite with the function.
This is useful for <em>SQLITE_INDEX_CONSTRAINT_FUNCTION</em> returns.</p>
<p>It isn’t possible to tell SQLite about exceptions in this function, so an
<a class="reference internal" href="exceptions.html#unraisable"><span class="std std-ref">unraisable exception</span></a> is used.</p>
<div class="admonition seealso">
<p class="admonition-title">See also</p>
<ul class="simple">
<li><p><a class="reference internal" href="connection.html#apsw.Connection.overload_function" title="apsw.Connection.overload_function"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Connection.overload_function()</span></code></a></p></li>
</ul>
</div>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xfindfunction_method">SQLite xFindFunction reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.Integrity">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">Integrity</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">schema</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">name</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">is_quick</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a><span class="w"> </span><span class="p"><span class="pre">|</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.VTTable.Integrity" title="Link to this definition"></a></dt>
<dd><p>If present, check the integrity of the virtual table.</p>
<dl class="field-list simple">
<dt class="field-odd">Parameters<span class="colon">:</span></dt>
<dd class="field-odd"><ul class="simple">
<li><p><strong>schema</strong> – Database name <cite>main</cite>, <cite>temp</cite>, the name in <a class="reference external" href="https://sqlite.org/lang_attach.html">ATTACH</a></p></li>
<li><p><strong>name</strong> – Name of the table</p></li>
<li><p><strong>is_quick</strong> – 0 if <a class="reference external" href="https://sqlite.org/pragma.html#pragma_integrity_check">pragma integrity_check</a> was used,
1 if <a class="reference external" href="https://sqlite.org/pragma.html#pragma_quick_check">pragma quick_check</a> was used, and may contain
other values in the future.</p></li>
</ul>
</dd>
<dt class="field-even">Returns<span class="colon">:</span></dt>
<dd class="field-even"><p>None if there are no problems, else a string to be used as an error message. The string is returned to the
pragma as is, so it is recommended that you include the database and table name to clarify what database and
table the message is referring to.</p>
</dd>
</dl>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xintegrity_method">SQLite xIntegrity reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.Open">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">Open</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference internal" href="#apsw.VTCursor" title="apsw.VTCursor"><span class="pre">VTCursor</span></a></span></span><a class="headerlink" href="#apsw.VTTable.Open" title="Link to this definition"></a></dt>
<dd><p>Returns a <a class="reference internal" href="#apsw.VTCursor" title="apsw.VTCursor"><code class="xref py py-class docutils literal notranslate"><span class="pre">cursor</span></code></a> object.</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xopen_method">SQLite xOpen reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.Release">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">Release</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">level</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.VTTable.Release" title="Link to this definition"></a></dt>
<dd><p>Release nested transactions back to <em>level</em>.</p>
<p>If you do not provide this method then the call succeeds (matching
SQLite behaviour when no callback is provided).</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xsavepoint_xrelease_and_xrollbackto_methods">SQLite xRelease reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.Rename">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">Rename</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">newname</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.VTTable.Rename" title="Link to this definition"></a></dt>
<dd><p>Notification that the table will be given a new name. If you return
without raising an exception, then SQLite renames the table (you
don’t have to do anything). If you raise an exception then the
renaming is prevented. You do not have to provide this method.</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xrename_method">SQLite xRename reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.Rollback">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">Rollback</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.VTTable.Rollback" title="Link to this definition"></a></dt>
<dd><p>This function is used as part of transactions. You do not have to
provide the method.</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xsavepoint_xrelease_and_xrollbackto_methods">SQLite xRollbackTo reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.Savepoint">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">Savepoint</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">level</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.VTTable.Savepoint" title="Link to this definition"></a></dt>
<dd><p>Set nested transaction to <em>level</em>.</p>
<p>If you do not provide this method then the call succeeds (matching
SQLite behaviour when no callback is provided).</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xsavepoint_xrelease_and_xrollbackto_methods">SQLite xSavepoint reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.Sync">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">Sync</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.VTTable.Sync" title="Link to this definition"></a></dt>
<dd><p>This function is used as part of transactions. You do not have to
provide the method.</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xsync_method">SQLite xSync reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.UpdateChangeRow">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">UpdateChangeRow</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">row</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">newrowid</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">fields</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#tuple" title="(in Python v3.12)"><span class="pre">tuple</span></a><span class="p"><span class="pre">[</span></span><a class="reference internal" href="apsw.html#apsw.SQLiteValue" title="apsw.SQLiteValue"><span class="pre">SQLiteValue</span></a><span class="p"><span class="pre">,</span></span><span class="w"> </span><span class="p"><span class="pre">...</span></span><span class="p"><span class="pre">]</span></span></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.VTTable.UpdateChangeRow" title="Link to this definition"></a></dt>
<dd><p>Change an existing row. You may also need to change the rowid - for example if the query was
<code class="docutils literal notranslate"><span class="pre">UPDATE</span> <span class="pre">table</span> <span class="pre">SET</span> <span class="pre">rowid=rowid+100</span> <span class="pre">WHERE</span> <span class="pre">...</span></code></p>
<dl class="field-list simple">
<dt class="field-odd">Parameters<span class="colon">:</span></dt>
<dd class="field-odd"><ul class="simple">
<li><p><strong>row</strong> – The existing 64 bit integer rowid</p></li>
<li><p><strong>newrowid</strong> – If not the same as <em>row</em> then also change the rowid to this.</p></li>
<li><p><strong>fields</strong> – A tuple of values the same length and order as columns in your table</p></li>
</ul>
</dd>
</dl>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xupdate_method">SQLite xUpdate reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.UpdateDeleteRow">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">UpdateDeleteRow</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">rowid</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.VTTable.UpdateDeleteRow" title="Link to this definition"></a></dt>
<dd><p>Delete the row with the specified <em>rowid</em>.</p>
<dl class="field-list simple">
<dt class="field-odd">Parameters<span class="colon">:</span></dt>
<dd class="field-odd"><p><strong>rowid</strong> – 64 bit integer</p>
</dd>
</dl>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xupdate_method">SQLite xUpdate reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTTable.UpdateInsertRow">
<span class="sig-prename descclassname"><span class="pre">VTTable.</span></span><span class="sig-name descname"><span class="pre">UpdateInsertRow</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">rowid</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a><span class="w"> </span><span class="p"><span class="pre">|</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">fields</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#tuple" title="(in Python v3.12)"><span class="pre">tuple</span></a><span class="p"><span class="pre">[</span></span><a class="reference internal" href="apsw.html#apsw.SQLiteValue" title="apsw.SQLiteValue"><span class="pre">SQLiteValue</span></a><span class="p"><span class="pre">,</span></span><span class="w"> </span><span class="p"><span class="pre">...</span></span><span class="p"><span class="pre">]</span></span></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a><span class="w"> </span><span class="p"><span class="pre">|</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.VTTable.UpdateInsertRow" title="Link to this definition"></a></dt>
<dd><p>Insert a row with the specified <em>rowid</em>.</p>
<dl class="field-list simple">
<dt class="field-odd">Parameters<span class="colon">:</span></dt>
<dd class="field-odd"><ul class="simple">
<li><p><strong>rowid</strong> – <em>None</em> if you should choose the rowid yourself, else a 64 bit integer</p></li>
<li><p><strong>fields</strong> – A tuple of values the same length and order as columns in your table</p></li>
</ul>
</dd>
<dt class="field-even">Returns<span class="colon">:</span></dt>
<dd class="field-even"><p>If <em>rowid</em> was <em>None</em> then return the id you assigned
to the row. If <em>rowid</em> was not <em>None</em> then the return value
is ignored.</p>
</dd>
</dl>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xupdate_method">SQLite xUpdate reference</a></p>
</dd></dl>
</section>
<section id="vtcursor-class">
<h2>VTCursor class<a class="headerlink" href="#vtcursor-class" title="Link to this heading"></a></h2>
<dl class="py class">
<dt class="sig sig-object py" id="apsw.VTCursor">
<em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">apsw.</span></span><span class="sig-name descname"><span class="pre">VTCursor</span></span><a class="headerlink" href="#apsw.VTCursor" title="Link to this definition"></a></dt>
<dd></dd></dl>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>There is no actual <em>VTCursor</em> class - it is shown this way for
documentation convenience and is present as a <a class="reference external" href="https://docs.python.org/3/library/typing.html#typing.Protocol">typing protocol</a>.</p>
</div>
<p>The <a class="reference internal" href="#apsw.VTCursor" title="apsw.VTCursor"><code class="xref py py-class docutils literal notranslate"><span class="pre">VTCursor</span></code></a> object is used for iterating over a table.
There may be many cursors simultaneously so each one needs to keep
track of where in the table it is.</p>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTCursor.Close">
<span class="sig-prename descclassname"><span class="pre">VTCursor.</span></span><span class="sig-name descname"><span class="pre">Close</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.VTCursor.Close" title="Link to this definition"></a></dt>
<dd><p>This is the destructor for the cursor. Note that you must
cleanup. The method will not be called again if you raise an
exception.</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xclose_method">SQLite xClose reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTCursor.Column">
<span class="sig-prename descclassname"><span class="pre">VTCursor.</span></span><span class="sig-name descname"><span class="pre">Column</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">number</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference internal" href="apsw.html#apsw.SQLiteValue" title="apsw.SQLiteValue"><span class="pre">SQLiteValue</span></a></span></span><a class="headerlink" href="#apsw.VTCursor.Column" title="Link to this definition"></a></dt>
<dd><p>Requests the value of the specified column <em>number</em> of the current
row. If <em>number</em> is -1 then return the rowid.</p>
<dl class="field-list simple">
<dt class="field-odd">Returns<span class="colon">:</span></dt>
<dd class="field-odd"><p>Must be one one of the <a class="reference internal" href="tips.html#types"><span class="std std-ref">5
supported types</span></a></p>
</dd>
</dl>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xcolumn_method">SQLite xColumn reference</a></p>
</dd></dl>
<dl class="py method" id="index-5">
<dt class="sig sig-object py" id="apsw.VTCursor.ColumnNoChange">
<span class="sig-prename descclassname"><span class="pre">VTCursor.</span></span><span class="sig-name descname"><span class="pre">ColumnNoChange</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">number</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference internal" href="apsw.html#apsw.SQLiteValue" title="apsw.SQLiteValue"><span class="pre">SQLiteValue</span></a></span></span><a class="headerlink" href="#apsw.VTCursor.ColumnNoChange" title="Link to this definition"></a></dt>
<dd><p><a class="reference internal" href="#apsw.VTTable.UpdateChangeRow" title="apsw.VTTable.UpdateChangeRow"><code class="xref py py-meth docutils literal notranslate"><span class="pre">VTTable.UpdateChangeRow()</span></code></a> is going to be called which includes
values for all columns. However this column is not going to be changed
in that update.</p>
<p>If you return <a class="reference internal" href="apsw.html#apsw.no_change" title="apsw.no_change"><code class="xref py py-attr docutils literal notranslate"><span class="pre">apsw.no_change</span></code></a> then <a class="reference internal" href="#apsw.VTTable.UpdateChangeRow" title="apsw.VTTable.UpdateChangeRow"><code class="xref py py-meth docutils literal notranslate"><span class="pre">VTTable.UpdateChangeRow()</span></code></a>
will have <a class="reference internal" href="apsw.html#apsw.no_change" title="apsw.no_change"><code class="xref py py-attr docutils literal notranslate"><span class="pre">apsw.no_change</span></code></a> for this column. If you return
anything else then it will have that value - as though <a class="reference internal" href="#apsw.VTCursor.Column" title="apsw.VTCursor.Column"><code class="xref py py-meth docutils literal notranslate"><span class="pre">VTCursor.Column()</span></code></a>
had been called.</p>
<p>This method will only be called if <em>use_no_change</em> was <em>True</em> in the
call to <a class="reference internal" href="connection.html#apsw.Connection.create_module" title="apsw.Connection.create_module"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Connection.create_module()</span></code></a>.</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xcolumn_method">SQLite xColumn reference</a></p>
<p>Calls: <a class="reference external" href="https://sqlite.org/c3ref/vtab_nochange.html">sqlite3_vtab_nochange</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTCursor.Eof">
<span class="sig-prename descclassname"><span class="pre">VTCursor.</span></span><span class="sig-name descname"><span class="pre">Eof</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/functions.html#bool" title="(in Python v3.12)"><span class="pre">bool</span></a></span></span><a class="headerlink" href="#apsw.VTCursor.Eof" title="Link to this definition"></a></dt>
<dd><p>Called to ask if we are at the end of the table. It is called after each call to Filter and Next.</p>
<dl class="field-list simple">
<dt class="field-odd">Returns<span class="colon">:</span></dt>
<dd class="field-odd"><p>False if the cursor is at a valid row of data, else True</p>
</dd>
</dl>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>This method can only return True or False to SQLite. If you have
an exception in the method or provide a non-boolean return then
True (no more data) will be returned to SQLite.</p>
</div>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xeof_method">SQLite xEof reference</a></p>
</dd></dl>
<dl class="py method" id="index-6">
<dt class="sig sig-object py" id="apsw.VTCursor.Filter">
<span class="sig-prename descclassname"><span class="pre">VTCursor.</span></span><span class="sig-name descname"><span class="pre">Filter</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">indexnum</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">indexname</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.12)"><span class="pre">str</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">constraintargs</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#tuple" title="(in Python v3.12)"><span class="pre">tuple</span></a><span class="w"> </span><span class="p"><span class="pre">|</span></span><span class="w"> </span><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.VTCursor.Filter" title="Link to this definition"></a></dt>
<dd><p>This method is always called first to initialize an iteration to the
first row of the table. The arguments come from the
<a class="reference internal" href="#apsw.VTTable.BestIndex" title="apsw.VTTable.BestIndex"><code class="xref py py-meth docutils literal notranslate"><span class="pre">BestIndex()</span></code></a> or <a class="reference internal" href="#apsw.VTTable.BestIndexObject" title="apsw.VTTable.BestIndexObject"><code class="xref py py-meth docutils literal notranslate"><span class="pre">BestIndexObject()</span></code></a>
with constraintargs being a tuple of the constraints you
requested. If you always return None in BestIndex then indexnum will
be zero, indexstring will be None and constraintargs will be empty).</p>
<p>If you had an <em>in</em> constraint and set <a class="reference internal" href="#apsw.IndexInfo.set_aConstraintUsage_in" title="apsw.IndexInfo.set_aConstraintUsage_in"><code class="xref py py-meth docutils literal notranslate"><span class="pre">IndexInfo.set_aConstraintUsage_in()</span></code></a>
then that value will be a <a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#set" title="(in Python v3.12)"><code class="xref py py-class docutils literal notranslate"><span class="pre">set</span></code></a>.</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xfilter_method">SQLite xFilter reference</a></p>
<dl class="simple">
<dt>Calls:</dt><dd><ul class="simple">
<li><p><a class="reference external" href="https://sqlite.org/c3ref/vtab_in_first.html">sqlite3_vtab_in_first</a></p></li>
<li><p><a class="reference external" href="https://sqlite.org/c3ref/vtab_in_first.html">sqlite3_vtab_in_next</a></p></li>
</ul>
</dd>
</dl>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTCursor.Next">
<span class="sig-prename descclassname"><span class="pre">VTCursor.</span></span><span class="sig-name descname"><span class="pre">Next</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.12)"><span class="pre">None</span></a></span></span><a class="headerlink" href="#apsw.VTCursor.Next" title="Link to this definition"></a></dt>
<dd><p>Move the cursor to the next row. Do not have an exception if there
is no next row. Instead return False when <a class="reference internal" href="#apsw.VTCursor.Eof" title="apsw.VTCursor.Eof"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Eof()</span></code></a> is
subsequently called.</p>
<p>If you said you had indices in your <a class="reference internal" href="#apsw.VTTable.BestIndex" title="apsw.VTTable.BestIndex"><code class="xref py py-meth docutils literal notranslate"><span class="pre">VTTable.BestIndex()</span></code></a>
return, and they were selected for use as provided in the parameters
to <a class="reference internal" href="#apsw.VTCursor.Filter" title="apsw.VTCursor.Filter"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Filter()</span></code></a> then you should move to the next
appropriate indexed and constrained row.</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xnext_method">SQLite xNext reference</a></p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="apsw.VTCursor.Rowid">
<span class="sig-prename descclassname"><span class="pre">VTCursor.</span></span><span class="sig-name descname"><span class="pre">Rowid</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">→</span> <span class="sig-return-typehint"><a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.12)"><span class="pre">int</span></a></span></span><a class="headerlink" href="#apsw.VTCursor.Rowid" title="Link to this definition"></a></dt>
<dd><p>Return the current rowid.</p>
<p><a class="reference external" href="https://sqlite.org/vtab.html#the_xrowid_method">SQLite xRowid reference</a></p>
</dd></dl>
</section>
</section>
</div>
</div>
<footer><div class="rst-footer-buttons" role="navigation" aria-label="Footer">
<a href="backup.html" class="btn btn-neutral float-left" title="Backup" accesskey="p" rel="prev"><span class="fa fa-arrow-circle-left" aria-hidden="true"></span> Previous</a>
<a href="vfs.html" class="btn btn-neutral float-right" title="Virtual File System (VFS)" accesskey="n" rel="next">Next <span class="fa fa-arrow-circle-right" aria-hidden="true"></span></a>
</div>
<hr/>
<div role="contentinfo">
<p>© <a href="copyright.html">Copyright</a> 2004-2024, Roger Binns <rogerb@rogerbinns.com>.
<span class="lastupdated">Last updated on Jun 16, 2024.
</span></p>
</div>
Built with <a href="https://www.sphinx-doc.org/">Sphinx</a> using a
<a href="https://github.com/readthedocs/sphinx_rtd_theme">theme</a>
provided by <a href="https://readthedocs.org">Read the Docs</a>.
</footer>
</div>
</div>
</section>
</div>
<script>
jQuery(function () {
SphinxRtdTheme.Navigation.enable(true);
});
</script>
</body>
</html>
|
