| blob | 1c31ca2338e619441c3a00ac2f22e17cc56b494b |
1 /*
2 ** 2001 September 15
3 **
4 ** The author disclaims copyright to this source code. In place of
5 ** a legal notice, here is a blessing:
6 **
7 ** May you do good and not evil.
8 ** May you find forgiveness for yourself and forgive others.
9 ** May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** This file contains C code routines that are called by the parser
13 ** to handle INSERT statements in SQLite.
14 */
17 /*
18 ** Generate code that will
19 **
20 ** (1) acquire a lock for table pTab then
21 ** (2) open pTab as cursor iCur.
22 **
23 ** If pTab is a WITHOUT ROWID table, then it is the PRIMARY KEY index
24 ** for that table that is actually opened.
25 */
32 ){
41 }
52 }
53 }
55 /*
56 ** Return a pointer to the column affinity string associated with index
57 ** pIdx. A column affinity string has one character for each column in
58 ** the table, according to the affinity of the column:
59 **
60 ** Character Column affinity
61 ** ------------------------------
62 ** 'A' BLOB
63 ** 'B' TEXT
64 ** 'C' NUMERIC
65 ** 'D' INTEGER
66 ** 'F' REAL
67 **
68 ** An extra 'D' is appended to the end of the string to cover the
69 ** rowid that appears as the last column in every index.
70 **
71 ** Memory for the buffer containing the column index affinity string
72 ** is managed along with the rest of the Index structure. It will be
73 ** released when sqlite3DeleteIndex() is called.
74 */
76 /* The first time a column affinity string for a particular index is
77 ** required, it is allocated and populated here. It is then stored as
78 ** a member of the Index structure for subsequent use.
79 **
80 ** The column affinity string will eventually be deleted by
81 ** sqliteDeleteIndex() when the Index structure itself is cleaned
82 ** up.
83 */
90 }
103 }
107 }
110 }
114 }
117 /*
118 ** Compute an affinity string for a table. Space is obtained
119 ** from sqlite3DbMalloc(). The caller is responsible for freeing
120 ** the space when done.
121 */
130 }
131 }
135 }
137 }
139 /*
140 ** Make changes to the evolving bytecode to do affinity transformations
141 ** of values that are about to be gathered into a row for table pTab.
142 **
143 ** For ordinary (legacy, non-strict) tables:
144 ** -----------------------------------------
145 **
146 ** Compute the affinity string for table pTab, if it has not already been
147 ** computed. As an optimization, omit trailing SQLITE_AFF_BLOB affinities.
148 **
149 ** If the affinity string is empty (because it was all SQLITE_AFF_BLOB entries
150 ** which were then optimized out) then this routine becomes a no-op.
151 **
152 ** Otherwise if iReg>0 then code an OP_Affinity opcode that will set the
153 ** affinities for register iReg and following. Or if iReg==0,
154 ** then just set the P4 operand of the previous opcode (which should be
155 ** an OP_MakeRecord) to the affinity string.
156 **
157 ** A column affinity string has one character per column:
158 **
159 ** Character Column affinity
160 ** --------- ---------------
161 ** 'A' BLOB
162 ** 'B' TEXT
163 ** 'C' NUMERIC
164 ** 'D' INTEGER
165 ** 'E' REAL
166 **
167 ** For STRICT tables:
168 ** ------------------
169 **
170 ** Generate an appropriate OP_TypeCheck opcode that will verify the
171 ** datatypes against the column definitions in pTab. If iReg==0, that
172 ** means an OP_MakeRecord opcode has already been generated and should be
173 ** the last opcode generated. The new OP_TypeCheck needs to be inserted
174 ** before the OP_MakeRecord. The new OP_TypeCheck should use the same
175 ** register set as the OP_MakeRecord. If iReg>0 then register iReg is
176 ** the first of a series of registers that will form the new record.
177 ** Apply the type checking to that array of registers.
178 */
184 /* Move the previous opcode (which should be OP_MakeRecord) forward
185 ** by one slot and insert a new OP_TypeCheck where the current
186 ** OP_MakeRecord is found */
195 /* Insert an isolated OP_Typecheck */
198 }
200 }
207 }
209 }
219 }
220 }
221 }
223 /*
224 ** Return non-zero if the table pTab in database iDb or any of its indices
225 ** have been opened at any point in the VDBE program. This is used to see if
226 ** a statement of the form "INSERT INTO <iDb, pTab> SELECT ..." can
227 ** run without using a temporary table for the results of the SELECT.
228 */
233 #ifndef SQLITE_OMIT_VIRTUALTABLE
235 #endif
245 }
249 }
250 }
251 }
252 #ifndef SQLITE_OMIT_VIRTUALTABLE
257 }
258 #endif
259 }
261 }
263 /* This walker callback will compute the union of colFlags flags for all
264 ** referenced columns in a CHECK constraint or generated column expression.
265 */
270 }
272 }
274 #ifndef SQLITE_OMIT_GENERATED_COLUMNS
275 /*
276 ** All regular columns for table pTab have been puts into registers
277 ** starting with iRegStore. The registers that correspond to STORED
278 ** or VIRTUAL columns have not yet been initialized. This routine goes
279 ** back and computes the values for those columns based on the previously
280 ** computed normal columns.
281 */
286 ){
288 Walker w;
297 /* Before computing generated columns, first go through and make sure
298 ** that appropriate affinity has been applied to the regular columns
299 */
304 /* Change the OP_Affinity argument to '@' (NONE) for all stored
305 ** columns. '@' is the no-op affinity and those columns have not
306 ** yet been computed. */
314 }
317 }
318 jj++;
319 }
321 /* If an OP_TypeCheck was generated because the table is STRICT,
322 ** then set the P3 operand to indicate that generated columns should
323 ** not be checked */
325 }
326 }
328 /* Because there can be multiple generated columns that refer to one another,
329 ** this is a two-pass algorithm. On the first pass, mark all generated
330 ** columns as "not available".
331 */
337 }
338 }
345 /* On the second pass, compute the value of each NOT-AVAILABLE column.
346 ** Companion code in the TK_COLUMN case of sqlite3ExprCodeTarget() will
347 ** compute dependencies and mark remove the COLSPAN_NOTAVAIL mark, as
348 ** they are needed.
349 */
365 }
371 }
372 }
376 }
378 }
382 #ifndef SQLITE_OMIT_AUTOINCREMENT
383 /*
384 ** Locate or create an AutoincInfo structure associated with table pTab
385 ** which is in database iDb. Return the register number for the register
386 ** that holds the maximum rowid. Return zero if pTab is not an AUTOINCREMENT
387 ** table. (Also return zero when doing a VACUUM since we do not want to
388 ** update the AUTOINCREMENT counters during a VACUUM.)
389 **
390 ** There is at most one AutoincInfo structure per table even if the
391 ** same table is autoincremented multiple times due to inserts within
392 ** triggers. A new AutoincInfo structure is created if this is the
393 ** first use of table pTab. On 2nd and subsequent uses, the original
394 ** AutoincInfo structure is used.
395 **
396 ** Four consecutive registers are allocated:
397 **
398 ** (1) The name of the pTab table.
399 ** (2) The maximum ROWID of pTab.
400 ** (3) The rowid in sqlite_sequence of pTab
401 ** (4) The original value of the max ROWID in pTab, or NULL if none
402 **
403 ** The 2nd register is the one that is returned. That is all the
404 ** insert routine needs to know about.
405 */
410 ){
415 ){
420 /* Verify that the sqlite_sequence table exists and is an ordinary
421 ** rowid table with exactly two columns.
422 ** Ticket d8dc2b3a58cd5dc2918a1d4acb 2018-05-23 */
427 ){
431 }
447 }
449 }
451 }
453 /*
454 ** This routine generates code that will initialize all of the
455 ** register used by the autoincrement tracker.
456 */
464 /* This routine is never called during trigger-generation. It is
465 ** only called from the top-level */
485 };
507 }
508 }
510 /*
511 ** Update the maximum rowid for an autoincrement calculation.
512 **
513 ** This routine should be called when the regRowid register holds a
514 ** new rowid that is about to be inserted. If that new rowid is
515 ** larger than the maximum rowid in the memId memory cell, then the
516 ** memory cell is updated.
517 */
521 }
522 }
524 /*
525 ** This routine generates the code needed to write autoincrement
526 ** maximum rowid values back into the sqlite_sequence register.
527 ** Every statement that might do an INSERT into an autoincrement
528 ** table (either directly or through triggers) needs to call this
529 ** routine just before the "exit" code.
530 */
545 };
566 }
567 }
570 }
571 #else
572 /*
573 ** If SQLITE_OMIT_AUTOINCREMENT is defined, then the three routines
574 ** above are all no-ops
575 */
576 # define autoIncBegin(A,B,C) (0)
577 # define autoIncStep(A,B,C)
581 /* Forward declaration */
588 );
590 /*
591 ** This routine is called to handle SQL of the following forms:
592 **
593 ** insert into TABLE (IDLIST) values(EXPRLIST),(EXPRLIST),...
594 ** insert into TABLE (IDLIST) select
595 ** insert into TABLE (IDLIST) default values
596 **
597 ** The IDLIST following the table name is always optional. If omitted,
598 ** then a list of all (non-hidden) columns for the table is substituted.
599 ** The IDLIST appears in the pColumn parameter. pColumn is NULL if IDLIST
600 ** is omitted.
601 **
602 ** For the pSelect parameter holds the values to be inserted for the
603 ** first two forms shown above. A VALUES clause is really just short-hand
604 ** for a SELECT statement that omits the FROM clause and everything else
605 ** that follows. If the pSelect parameter is NULL, that means that the
606 ** DEFAULT VALUES form of the INSERT statement is intended.
607 **
608 ** The code generated follows one of four templates. For a simple
609 ** insert with data coming from a single-row VALUES clause, the code executes
610 ** once straight down through. Pseudo-code follows (we call this
611 ** the "1st template"):
612 **
613 ** open write cursor to <table> and its indices
614 ** put VALUES clause expressions into registers
615 ** write the resulting record into <table>
616 ** cleanup
617 **
618 ** The three remaining templates assume the statement is of the form
619 **
620 ** INSERT INTO <table> SELECT ...
621 **
622 ** If the SELECT clause is of the restricted form "SELECT * FROM <table2>" -
623 ** in other words if the SELECT pulls all columns from a single table
624 ** and there is no WHERE or LIMIT or GROUP BY or ORDER BY clauses, and
625 ** if <table2> and <table1> are distinct tables but have identical
626 ** schemas, including all the same indices, then a special optimization
627 ** is invoked that copies raw records from <table2> over to <table1>.
628 ** See the xferOptimization() function for the implementation of this
629 ** template. This is the 2nd template.
630 **
631 ** open a write cursor to <table>
632 ** open read cursor on <table2>
633 ** transfer all records in <table2> over to <table>
634 ** close cursors
635 ** foreach index on <table>
636 ** open a write cursor on the <table> index
637 ** open a read cursor on the corresponding <table2> index
638 ** transfer all records from the read to the write cursors
639 ** close cursors
640 ** end foreach
641 **
642 ** The 3rd template is for when the second template does not apply
643 ** and the SELECT clause does not read from <table> at any time.
644 ** The generated code follows this template:
645 **
646 ** X <- A
647 ** goto B
648 ** A: setup for the SELECT
649 ** loop over the rows in the SELECT
650 ** load values into registers R..R+n
651 ** yield X
652 ** end loop
653 ** cleanup after the SELECT
654 ** end-coroutine X
655 ** B: open write cursor to <table> and its indices
656 ** C: yield X, at EOF goto D
657 ** insert the select result into <table> from R..R+n
658 ** goto C
659 ** D: cleanup
660 **
661 ** The 4th template is used if the insert statement takes its
662 ** values from a SELECT but the data is being inserted into a table
663 ** that is also read as part of the SELECT. In the third form,
664 ** we have to use an intermediate table to store the results of
665 ** the select. The template is like this:
666 **
667 ** X <- A
668 ** goto B
669 ** A: setup for the SELECT
670 ** loop over the tables in the SELECT
671 ** load value into register R..R+n
672 ** yield X
673 ** end loop
674 ** cleanup after the SELECT
675 ** end co-routine R
676 ** B: open temp table
677 ** L: yield X, at EOF goto M
678 ** insert row from R..R+n into temp table
679 ** goto L
680 ** M: open write cursor to <table> and its indices
681 ** rewind temp table
682 ** C: loop over rows of intermediate table
683 ** transfer values form intermediate table into <table>
684 ** end loop
685 ** D: cleanup
686 */
694 ){
718 /* Register allocations */
727 #ifndef SQLITE_OMIT_TRIGGER
731 #endif
737 }
741 /* If the Select object is really just a simple VALUES() list with a
742 ** single row (the common case) then keep that one row of values
743 ** and discard the other (unused) parts of the pSelect object
744 */
750 }
752 /* Locate the table into which we will be inserting new information.
753 */
758 }
764 }
767 /* Figure out if we have any triggers and if the table being
768 ** inserted into is a view
769 */
770 #ifndef SQLITE_OMIT_TRIGGER
773 #else
774 # define pTrigger 0
775 # define tmask 0
776 # define isView 0
777 #endif
778 #ifdef SQLITE_OMIT_VIEW
779 # undef isView
780 # define isView 0
781 #endif
784 #if TREETRACE_ENABLED
789 }
790 #endif
792 /* If pTab is really a view, make sure it has been initialized.
793 ** ViewGetColumnNames() is a no-op if pTab is not a view.
794 */
797 }
799 /* Cannot insert into a read-only table.
800 */
803 }
805 /* Allocate a VDBE
806 */
812 #ifndef SQLITE_OMIT_XFER_OPT
813 /* If the statement is of the form
814 **
815 ** INSERT INTO <table1> SELECT * FROM <table2>;
816 **
817 ** Then special optimizations can be applied that make the transfer
818 ** very fast and which reduce fragmentation of indices.
819 **
820 ** This is the 2nd template.
821 */
826 ){
830 }
833 /* If this is an AUTOINCREMENT table, look up the sequence number in the
834 ** sqlite_sequence table and store it in memory cell regAutoinc.
835 */
838 /* Allocate a block registers to hold the rowid and the values
839 ** for all columns of the new row.
840 */
844 regRowid++;
846 }
849 /* If the INSERT statement included an IDLIST term, then make sure
850 ** all elements of the IDLIST really are columns of the table and
851 ** remember the column indices.
852 **
853 ** If the table has an INTEGER PRIMARY KEY column and that column
854 ** is named in the IDLIST, then record in the ipkColumn variable
855 ** the index into IDLIST of the primary key column. ipkColumn is
856 ** the index of the primary key as it appears in IDLIST, not as
857 ** is appears in the original table. (The index of the INTEGER
858 ** PRIMARY KEY in the original table is pTab->iPKey.) After this
859 ** loop, if ipkColumn==(-1), that means that integer primary key
860 ** is unspecified, and hence the table is either WITHOUT ROWID or
861 ** it will automatically generated an integer primary key.
862 **
863 ** bIdListInOrder is true if the columns in IDLIST are in storage
864 ** order. This enables an optimization that avoids shuffling the
865 ** columns into storage order. False negatives are harmless,
866 ** but false positives will cause database corruption.
867 */
874 }
882 }
883 #ifndef SQLITE_OMIT_GENERATED_COLUMNS
889 }
890 #endif
892 }
893 }
903 }
904 }
905 }
906 }
908 /* Figure out how many columns of data are supplied. If the data
909 ** is coming from a SELECT statement, then generate a co-routine that
910 ** produces a single row of the SELECT on each invocation. The
911 ** co-routine is the common header to the 3rd and 4th templates.
912 */
914 /* Data is coming from a SELECT or from a multi-row VALUES clause.
915 ** Generate a co-routine to run the SELECT. */
936 /* Set useTempTable to TRUE if the result of the SELECT statement
937 ** should be written into a temporary table (template 4). Set to
938 ** FALSE if each output row of the SELECT can be written directly into
939 ** the destination table (template 3).
940 **
941 ** A temp table must be used if the table being updated is also one
942 ** of the tables being read by the SELECT statement. Also use a
943 ** temp table in the case of row triggers.
944 */
947 }
950 /* Invoke the coroutine to extract information from the SELECT
951 ** and add it to a transient table srcTab. The code generated
952 ** here is from the 4th template:
953 **
954 ** B: open temp table
955 ** L: yield X, goto M at EOF
956 ** insert row from R..R+n into temp table
957 ** goto L
958 ** M: ...
959 */
976 }
978 /* This is the case if the data for the INSERT is coming from a
979 ** single-row VALUES clause
980 */
981 NameContext sNC;
990 }
993 }
994 }
996 /* If there is no IDLIST term but the table has an integer primary
997 ** key, the set the ipkColumn variable to the integer primary key
998 ** column index in the original table definition.
999 */
1002 #ifndef SQLITE_OMIT_GENERATED_COLUMNS
1010 ipkColumn--;
1011 }
1012 }
1013 }
1014 #endif
1016 /* Make sure the number of columns in the source data matches the number
1017 ** of columns to be inserted into the table.
1018 */
1025 }
1026 }
1032 }
1033 }
1037 }
1039 /* Initialize the count of rows to be inserted
1040 */
1045 ){
1048 }
1050 /* If this is not a view, open the table and and all indices */
1058 }
1063 }
1065 }
1066 #ifndef SQLITE_OMIT_UPSERT
1073 }
1077 }
1080 }
1091 }
1092 }
1095 }
1096 #endif
1099 /* This is the top of the main insertion loop */
1101 /* This block codes the top of loop only. The complete loop is the
1102 ** following pseudocode (template 4):
1103 **
1104 ** rewind temp table, if empty goto D
1105 ** C: loop over rows of intermediate table
1106 ** transfer values form intermediate table into <table>
1107 ** end loop
1108 ** D: ...
1109 */
1113 /* This block codes the top of loop only. The complete loop is the
1114 ** following pseudocode (template 3):
1115 **
1116 ** C: yield X, at EOF goto D
1117 ** insert the select result into <table> from R..R+n
1118 ** goto C
1119 ** D: ...
1120 */
1125 /* tag-20191021-001: If the INTEGER PRIMARY KEY is being generated by the
1126 ** SELECT, go ahead and copy the value into the rowid slot now, so that
1127 ** the value does not get overwritten by a NULL at tag-20191021-002. */
1129 }
1130 }
1132 /* Compute data for ordinary columns of the new entry. Values
1133 ** are written in storage order into registers starting with regData.
1134 ** Only ordinary columns are computed in this loop. The rowid
1135 ** (if there is one) is computed later and generated columns are
1136 ** computed after the rowid since they might depend on the value
1137 ** of the rowid.
1138 */
1143 u32 colFlags;
1146 /* tag-20191021-002: References to the INTEGER PRIMARY KEY are filled
1147 ** using the rowid. So put a NULL in the IPK slot of the record to avoid
1148 ** using excess space. The file format definition requires this extra
1149 ** NULL - we cannot optimize further by skipping the column completely */
1152 }
1154 nHidden++;
1156 /* Virtual columns do not participate in OP_MakeRecord. So back up
1157 ** iRegStore by one slot to compensate for the iRegStore++ in the
1158 ** outer for() loop */
1159 iRegStore--;
1162 /* Stored columns are computed later. But if there are BEFORE
1163 ** triggers, the slots used for stored columns will be OP_Copy-ed
1164 ** to a second block of registers, so the register needs to be
1165 ** initialized to NULL to avoid an uninitialized register read */
1168 }
1171 /* Hidden columns that are not explicitly named in the INSERT
1172 ** get there default value */
1175 iRegStore);
1177 }
1178 }
1183 /* A column not named in the insert column list gets its
1184 ** default value */
1187 iRegStore);
1189 }
1192 /* This is INSERT INTO ... DEFAULT VALUES. Load the default value. */
1195 iRegStore);
1199 }
1206 }
1213 }
1214 }
1215 }
1218 /* Run the BEFORE and INSTEAD OF triggers, if there are any
1219 */
1224 /* build the NEW.* reference row. Note that if there is an INTEGER
1225 ** PRIMARY KEY into which a NULL is being inserted, that NULL will be
1226 ** translated into a unique ID for the row. But on a BEFORE trigger,
1227 ** we do not know what the unique ID will be (because the insert has
1228 ** not happened yet) so we substitute a rowid of -1
1229 */
1240 }
1245 }
1247 /* Copy the new data already generated. */
1251 #ifndef SQLITE_OMIT_GENERATED_COLUMNS
1252 /* Compute the new value for generated columns after all other
1253 ** columns have already been computed. This must be done after
1254 ** computing the ROWID in case one of the generated columns
1255 ** refers to the ROWID. */
1260 }
1261 #endif
1263 /* If this is an INSERT on a view with an INSTEAD OF INSERT trigger,
1264 ** do not attempt any conversions before assembling the record.
1265 ** If this is a real table, attempt conversions as required by the
1266 ** table column affinities.
1267 */
1270 }
1272 /* Fire BEFORE or INSTEAD OF triggers */
1277 }
1281 /* The row that the VUpdate opcode will delete: none */
1283 }
1285 /* Compute the new rowid */
1289 /* Rowid already initialized at tag-20191021-001 */
1297 }
1298 }
1299 /* If the PRIMARY KEY expression is NULL, then use OP_NewRowid
1300 ** to generate a unique primary key value.
1301 */
1311 }
1313 }
1319 }
1322 #ifndef SQLITE_OMIT_GENERATED_COLUMNS
1323 /* Compute the new value for generated columns after all other
1324 ** columns have already been computed. This must be done after
1325 ** computing the ROWID in case one of the generated columns
1326 ** is derived from the INTEGER PRIMARY KEY. */
1329 }
1330 #endif
1332 /* Generate code to check constraints and generate index keys and
1333 ** do the insertion.
1334 */
1335 #ifndef SQLITE_OMIT_VIRTUALTABLE
1343 #endif
1344 {
1349 );
1352 }
1354 /* Set the OPFLAG_USESEEKRESULT flag if either (a) there are no REPLACE
1355 ** constraints or (b) there are no triggers and this table is not a
1356 ** parent table in a foreign key constraint. It is safe to set the
1357 ** flag in the second case as if any REPLACE constraint is hit, an
1358 ** OP_Delete or OP_IdxDelete instruction will be executed on each
1359 ** cursor that is disturbed. And these instructions both clear the
1360 ** VdbeCursor.seekResult variable, disabling the OPFLAG_USESEEKRESULT
1361 ** functionality. */
1365 );
1366 }
1367 #ifdef SQLITE_ALLOW_ROWID_IN_VIEW
1369 /* If there is a RETURNING clause, populate the rowid register with
1370 ** constant value -1, in case one or more of the returned expressions
1371 ** refer to the "rowid" of the view. */
1373 #endif
1374 }
1376 /* Update the count of rows that are inserted
1377 */
1380 }
1383 /* Code AFTER triggers */
1386 }
1388 /* The bottom of the main insertion loop, if the data source
1389 ** is a SELECT statement.
1390 */
1398 #ifdef SQLITE_DEBUG
1399 /* If we are jumping back to an OP_Yield that is preceded by an
1400 ** OP_ReleaseReg, set the p5 flag on the OP_Goto so that the
1401 ** OP_ReleaseReg will be included in the loop. */
1405 }
1406 #endif
1408 }
1410 #ifndef SQLITE_OMIT_XFER_OPT
1411 insert_end:
1413 /* Update the sqlite_sequence table by storing the content of the
1414 ** maximum rowid counter values recorded while inserting into
1415 ** autoincrement tables.
1416 */
1419 }
1421 /*
1422 ** Return the number of rows inserted. If this routine is
1423 ** generating code because of a call to sqlite3NestedParse(), do not
1424 ** invoke the callback function.
1425 */
1428 }
1430 insert_cleanup:
1437 }
1439 /* Make sure "isView" and other macros defined above are undefined. Otherwise
1440 ** they may interfere with compilation of other functions in this file
1441 ** (or in another file, if this file becomes part of the amalgamation). */
1442 #ifdef isView
1443 #undef isView
1444 #endif
1445 #ifdef pTrigger
1446 #undef pTrigger
1447 #endif
1448 #ifdef tmask
1449 #undef tmask
1450 #endif
1452 /*
1453 ** Meanings of bits in of pWalker->eCode for
1454 ** sqlite3ExprReferencesUpdatedColumn()
1455 */
1459 /* This is the Walker callback from sqlite3ExprReferencesUpdatedColumn().
1460 * Set bit 0x01 of pWalker->eCode if pWalker->eCode to 0 and if this
1461 ** expression node references any of the
1462 ** columns that are being modified by an UPDATE statement.
1463 */
1470 }
1473 }
1474 }
1476 }
1478 /*
1479 ** pExpr is a CHECK constraint on a row that is being UPDATE-ed. The
1480 ** only columns that are modified by the UPDATE are those for which
1481 ** aiChng[i]>=0, and also the ROWID is modified if chngRowid is true.
1482 **
1483 ** Return true if CHECK constraint pExpr uses any of the
1484 ** changing columns (or the rowid if it is changing). In other words,
1485 ** return true if this CHECK constraint must be validated for
1486 ** the new row in the UPDATE statement.
1487 **
1488 ** 2018-09-15: pExpr might also be an expression for an index-on-expressions.
1489 ** The operation of this routine is the same - return true if an only if
1490 ** the expression uses one or more of columns identified by the second and
1491 ** third arguments.
1492 */
1497 ){
1498 Walker w;
1507 }
1513 }
1515 /*
1516 ** The sqlite3GenerateConstraintChecks() routine usually wants to visit
1517 ** the indexes of a table in the order provided in the Table->pIndex list.
1518 ** However, sometimes (rarely - when there is an upsert) it wants to visit
1519 ** the indexes in a different order. The following data structures accomplish
1520 ** this.
1521 **
1522 ** The IndexIterator object is used to walk through all of the indexes
1523 ** of a table in either Index.pNext order, or in some other order established
1524 ** by an array of IndexListTerm objects.
1525 */
1540 };
1542 /* When IndexIterator.eType==1, then each index is an array of instances
1543 ** of the following object
1544 */
1548 };
1550 /* Return the first index on the list */
1559 }
1560 }
1562 /* Return the next index from the list. Return NULL when out of indexes */
1569 }
1576 }
1577 }
1579 /*
1580 ** Generate code to do constraint checks prior to an INSERT or an UPDATE
1581 ** on table pTab.
1582 **
1583 ** The regNewData parameter is the first register in a range that contains
1584 ** the data to be inserted or the data after the update. There will be
1585 ** pTab->nCol+1 registers in this range. The first register (the one
1586 ** that regNewData points to) will contain the new rowid, or NULL in the
1587 ** case of a WITHOUT ROWID table. The second register in the range will
1588 ** contain the content of the first table column. The third register will
1589 ** contain the content of the second table column. And so forth.
1590 **
1591 ** The regOldData parameter is similar to regNewData except that it contains
1592 ** the data prior to an UPDATE rather than afterwards. regOldData is zero
1593 ** for an INSERT. This routine can distinguish between UPDATE and INSERT by
1594 ** checking regOldData for zero.
1595 **
1596 ** For an UPDATE, the pkChng boolean is true if the true primary key (the
1597 ** rowid for a normal table or the PRIMARY KEY for a WITHOUT ROWID table)
1598 ** might be modified by the UPDATE. If pkChng is false, then the key of
1599 ** the iDataCur content table is guaranteed to be unchanged by the UPDATE.
1600 **
1601 ** For an INSERT, the pkChng boolean indicates whether or not the rowid
1602 ** was explicitly specified as part of the INSERT statement. If pkChng
1603 ** is zero, it means that the either rowid is computed automatically or
1604 ** that the table is a WITHOUT ROWID table and has no rowid. On an INSERT,
1605 ** pkChng will only be true if the INSERT statement provides an integer
1606 ** value for either the rowid column or its INTEGER PRIMARY KEY alias.
1607 **
1608 ** The code generated by this routine will store new index entries into
1609 ** registers identified by aRegIdx[]. No index entry is created for
1610 ** indices where aRegIdx[i]==0. The order of indices in aRegIdx[] is
1611 ** the same as the order of indices on the linked list of indices
1612 ** at pTab->pIndex.
1613 **
1614 ** (2019-05-07) The generated code also creates a new record for the
1615 ** main table, if pTab is a rowid table, and stores that record in the
1616 ** register identified by aRegIdx[nIdx] - in other words in the first
1617 ** entry of aRegIdx[] past the last index. It is important that the
1618 ** record be generated during constraint checks to avoid affinity changes
1619 ** to the register content that occur after constraint checks but before
1620 ** the new record is inserted.
1621 **
1622 ** The caller must have already opened writeable cursors on the main
1623 ** table and all applicable indices (that is to say, all indices for which
1624 ** aRegIdx[] is not zero). iDataCur is the cursor for the main table when
1625 ** inserting or updating a rowid table, or the cursor for the PRIMARY KEY
1626 ** index when operating on a WITHOUT ROWID table. iIdxCur is the cursor
1627 ** for the first index in the pTab->pIndex list. Cursors for other indices
1628 ** are at iIdxCur+N for the N-th element of the pTab->pIndex list.
1629 **
1630 ** This routine also generates code to check constraints. NOT NULL,
1631 ** CHECK, and UNIQUE constraints are all checked. If a constraint fails,
1632 ** then the appropriate action is performed. There are five possible
1633 ** actions: ROLLBACK, ABORT, FAIL, REPLACE, and IGNORE.
1634 **
1635 ** Constraint type Action What Happens
1636 ** --------------- ---------- ----------------------------------------
1637 ** any ROLLBACK The current transaction is rolled back and
1638 ** sqlite3_step() returns immediately with a
1639 ** return code of SQLITE_CONSTRAINT.
1640 **
1641 ** any ABORT Back out changes from the current command
1642 ** only (do not do a complete rollback) then
1643 ** cause sqlite3_step() to return immediately
1644 ** with SQLITE_CONSTRAINT.
1645 **
1646 ** any FAIL Sqlite3_step() returns immediately with a
1647 ** return code of SQLITE_CONSTRAINT. The
1648 ** transaction is not rolled back and any
1649 ** changes to prior rows are retained.
1650 **
1651 ** any IGNORE The attempt in insert or update the current
1652 ** row is skipped, without throwing an error.
1653 ** Processing continues with the next row.
1654 ** (There is an immediate jump to ignoreDest.)
1655 **
1656 ** NOT NULL REPLACE The NULL value is replace by the default
1657 ** value for that column. If the default value
1658 ** is NULL, the action is the same as ABORT.
1659 **
1660 ** UNIQUE REPLACE The other row that conflicts with the row
1661 ** being inserted is removed.
1662 **
1663 ** CHECK REPLACE Illegal. The results in an exception.
1664 **
1665 ** Which action to take is determined by the overrideError parameter.
1666 ** Or if overrideError==OE_Default, then the pParse->onError parameter
1667 ** is used. Or if pParse->onError==OE_Default then the onError value
1668 ** for the constraint is used.
1669 */
1684 ){
1702 /* Variables associated with retesting uniqueness constraints after
1703 ** replace triggers fire have run */
1718 /* pPk is the PRIMARY KEY index for WITHOUT ROWID tables and NULL for
1719 ** normal rowid tables. nPkField is the number of key fields in the
1720 ** pPk index or 1 for a rowid table. In other words, nPkField is the
1721 ** number of fields in the true primary key of the table. */
1728 }
1730 /* Record that this module has started */
1734 /* Test all NOT NULL constraints.
1735 */
1749 }
1752 nGenerated++;
1754 }
1756 /* Do not check NOT NULL on columns that do not change */
1758 }
1763 }
1767 ){
1774 }
1777 }
1787 nSeenReplace++;
1792 }
1795 /* no break */ deliberate_fall_through
1807 }
1813 }
1817 /* If there are no generated columns with NOT NULL constraints
1818 ** and no NOT NULL ON CONFLICT REPLACE constraints, then a single
1819 ** pass is sufficient */
1821 }
1824 #ifndef SQLITE_OMIT_GENERATED_COLUMNS
1826 /* If any NOT NULL ON CONFLICT REPLACE constraints fired on the
1827 ** first pass, recomputed values for all generated columns, as
1828 ** those values might depend on columns affected by the REPLACE.
1829 */
1831 }
1832 #endif
1836 /* Test all CHECK constraints
1837 */
1838 #ifndef SQLITE_OMIT_CHECK
1849 ){
1850 /* The check constraints do not reference any of the columns being
1851 ** updated so there is no point it verifying the check constraint */
1853 }
1857 }
1863 }
1873 P5_ConstraintCheck);
1874 }
1876 }
1878 }
1881 /* UNIQUE and PRIMARY KEY constraints should be handled in the following
1882 ** order:
1883 **
1884 ** (1) OE_Update
1885 ** (2) OE_Abort, OE_Fail, OE_Rollback, OE_Ignore
1886 ** (3) OE_Replace
1887 **
1888 ** OE_Fail and OE_Ignore must happen before any changes are made.
1889 ** OE_Update guarantees that only a single row will change, so it
1890 ** must happen before OE_Replace. Technically, OE_Abort and OE_Rollback
1891 ** could happen in any order, but they are grouped up front for
1892 ** convenience.
1893 **
1894 ** 2018-08-14: Ticket https://www.sqlite.org/src/info/908f001483982c43
1895 ** The order of constraints used to have OE_Update as (2) and OE_Abort
1896 ** and so forth as (1). But apparently PostgreSQL checks the OE_Update
1897 ** constraint before any others, so it had to be moved.
1898 **
1899 ** Constraint checking code is generated in this order:
1900 ** (A) The rowid constraint
1901 ** (B) Unique index constraints that do not have OE_Replace as their
1902 ** default conflict resolution strategy
1903 ** (C) Unique index that do use OE_Replace by default.
1904 **
1905 ** The ordering of (2) and (3) is accomplished by making sure the linked
1906 ** list of indexes attached to a table puts all OE_Replace indexes last
1907 ** in the list. See sqlite3CreateIndex() for where that happens.
1908 */
1915 /* There is just on ON CONFLICT clause and it has no constraint-target */
1918 /* A single ON CONFLICT DO NOTHING clause, without a constraint-target.
1919 ** Make all unique constraint resolution be OE_Ignore */
1923 /* A single ON CONFLICT DO UPDATE. Make all resolutions OE_Update */
1925 }
1927 /* Otherwise, we'll need to run the IndexListTerm array version of the
1928 ** iterator to ensure that all of the ON CONFLICT conditions are
1929 ** checked first and in order. */
1931 u64 nByte;
1936 }
1951 jj++;
1952 }
1957 i++;
1958 }
1963 i++;
1964 }
1966 }
1967 }
1969 /* Determine if it is possible that triggers (either explicitly coded
1970 ** triggers or FK resolution actions) might run as a result of deletes
1971 ** that happen when OE_Replace conflict resolution occurs. (Call these
1972 ** "replace triggers".) If any replace triggers run, we will need to
1973 ** recheck all of the uniqueness constraints after they have all run.
1974 ** But on the recheck, the resolution is OE_Abort instead of OE_Replace.
1975 **
1976 ** If replace triggers are a possibility, then
1977 **
1978 ** (1) Allocate register regTrigCnt and initialize it to zero.
1979 ** That register will count the number of replace triggers that
1980 ** fire. Constraint recheck only occurs if the number is positive.
1981 ** (2) Initialize pTrigger to the list of all DELETE triggers on pTab.
1982 ** (3) Initialize addrRecheck and lblRecheckOk
1983 **
1984 ** The uniqueness rechecking code will create a series of tests to run
1985 ** in a second pass. The addrRecheck and lblRecheckOk variables are
1986 ** used to link together these tests which are separated from each other
1987 ** in the generate bytecode.
1988 */
1990 /* There are not DELETE triggers nor FK constraints. No constraint
1991 ** rechecks are needed. */
2001 }
2003 /* Replace triggers might exist. Allocate the counter and
2004 ** initialize it to zero. */
2010 }
2011 }
2013 /* If rowid is changing, make sure the new rowid does not previously
2014 ** exist in the table.
2015 */
2019 /* Figure out what action to take in case of a rowid collision */
2025 }
2027 /* figure out whether or not upsert applies in this case */
2035 }
2036 }
2038 /* The first ON CONFLICT clause has a conflict target other than
2039 ** the IPK. We have to jump ahead to that first ON CONFLICT clause
2040 ** and then come back here and deal with the IPK afterwards */
2042 }
2043 }
2045 /* If the response to a rowid conflict is REPLACE but the response
2046 ** to some other UNIQUE constraint is FAIL or IGNORE, then we need
2047 ** to defer the running of the rowid conflict checking until after
2048 ** the UNIQUE constraints have run.
2049 */
2054 ){
2057 }
2060 /* pkChng!=0 does not mean that the rowid has changed, only that
2061 ** it might have changed. Skip the conflict logic below if the rowid
2062 ** is unchanged. */
2066 }
2068 /* Check to see if the new rowid already exists in the table. Skip
2069 ** the following conflict logic if it does not. */
2078 /* no break */ deliberate_fall_through
2079 }
2088 }
2090 /* If there are DELETE triggers on this table and the
2091 ** recursive-triggers flag is set, call GenerateRowDelete() to
2092 ** remove the conflicting row from the table. This will fire
2093 ** the triggers and remove both the table and index b-tree entries.
2094 **
2095 ** Otherwise, if there are no triggers or the recursive-triggers
2096 ** flag is not set, but the table has one or more indexes, call
2097 ** GenerateRowIndexDelete(). This removes the index b-tree entries
2098 ** only. The table b-tree entry will be replaced by the new entry
2099 ** when it is inserted.
2100 **
2101 ** If either GenerateRowDelete() or GenerateRowIndexDelete() is called,
2102 ** also invoke MultiWrite() to indicate that this VDBE may require
2103 ** statement rollback (if the statement is aborted after the delete
2104 ** takes place). Earlier versions called sqlite3MultiWrite() regardless,
2105 ** but being more selective here allows statements like:
2106 **
2107 ** REPLACE INTO t(rowid) VALUES($newrowid)
2108 **
2109 ** to run without a statement journal if there are no indexes on the
2110 ** table.
2111 */
2117 nReplaceTrig++;
2119 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
2121 /* This OP_Delete opcode fires the pre-update-hook only. It does
2122 ** not modify the b-tree. It is more efficient to let the coming
2123 ** OP_Insert replace the existing entry than it is to delete the
2124 ** existing entry and then insert a new one. */
2131 }
2132 }
2135 }
2136 #ifndef SQLITE_OMIT_UPSERT
2139 /* no break */ deliberate_fall_through
2140 }
2141 #endif
2146 }
2147 }
2154 }
2155 }
2157 /* Test all UNIQUE constraints by creating entries for each UNIQUE
2158 ** index and making sure that duplicate entries do not already exist.
2159 ** Compute the revised record entries for indices as we go.
2160 **
2161 ** This loop also handles the case of the PRIMARY KEY index for a
2162 ** WITHOUT ROWID table.
2163 */
2165 pIdx;
2167 ){
2179 }
2180 }
2185 }
2190 /* Skip partial indices for which the WHERE clause is not true */
2195 SQLITE_JUMPIFNULL);
2197 }
2199 /* Create a record for this index entry as it should appear after
2200 ** the insert or update. Store that record in the aRegIdx[ix] register
2201 */
2220 }
2221 }
2224 #ifdef SQLITE_ENABLE_NULL_TRIM
2227 }
2228 #endif
2231 /* In an UPDATE operation, if this index is the PRIMARY KEY index
2232 ** of a WITHOUT ROWID table and there has been no change the
2233 ** primary key, then no collision is possible. The collision detection
2234 ** logic below can all be skipped. */
2238 }
2240 /* Find out what action to take in case there is a uniqueness conflict */
2245 }
2250 }
2252 /* Figure out if the upsert clause applies to this index */
2258 }
2259 }
2261 /* Collision detection may be omitted if all of the following are true:
2262 ** (1) The conflict resolution algorithm is REPLACE
2263 ** (2) The table is a WITHOUT ROWID table
2264 ** (3) There are no secondary indexes on the table
2265 ** (4) No delete triggers need to be fired if there is a conflict
2266 ** (5) No FK constraint counters need to be updated if a conflict occurs.
2267 **
2268 ** This is not possible for ENABLE_PREUPDATE_HOOK builds, as the row
2269 ** must be explicitly deleted in order to ensure any pre-update hook
2270 ** is invoked. */
2272 #ifndef SQLITE_ENABLE_PREUPDATE_HOOK
2280 ){
2283 }
2286 /* Check to see if the new index entry will be unique */
2288 addrConflictCk =
2292 /* Generate code to handle collisions */
2297 /* Conflict only if the rowid of the existing index entry
2298 ** is different from old-rowid */
2303 }
2306 /* Extract the PRIMARY KEY from the end of the index entry and
2307 ** store it in registers regR..regR+nPk-1 */
2315 }
2316 }
2318 /* If currently processing the PRIMARY KEY of a WITHOUT ROWID
2319 ** table, only conflict if the new PRIMARY KEY values are actually
2320 ** different from the old. See TH3 withoutrowid04.test.
2321 **
2322 ** For a UNIQUE index, only conflict if the PRIMARY KEY values
2323 ** of the matched index row are different from the original PRIMARY
2324 ** KEY values of this row before the update. */
2336 }
2340 );
2344 }
2345 }
2346 }
2347 }
2349 /* Generate code that executes if the new index entry is not unique */
2361 }
2362 #ifndef SQLITE_OMIT_UPSERT
2365 /* no break */ deliberate_fall_through
2366 }
2367 #endif
2372 }
2383 nReplaceTrig++;
2384 }
2387 }
2393 }
2401 /* Here we insert code that will be invoked after all constraint
2402 ** checks have run, if and only if one or more replace triggers
2403 ** fired. */
2407 /* Bypass the recheck if this partial index is not defined
2408 ** for the current row */
2411 }
2412 /* Copy the constraint check code from above, except change
2413 ** the constraint-ok jump destination to be the address of
2414 ** the next retest block */
2417 /* The sqlite3VdbeAddOp4() call might reallocate the opcode array.
2418 ** Hence, make a complete copy of the opcode, rather than using
2419 ** a pointer to the opcode. */
2428 }
2433 }
2434 nConflictCk--;
2435 addrConflictCk++;
2436 }
2437 /* If the retest fails, issue an abort */
2441 }
2444 }
2445 }
2449 && upsertIpkReturn
2451 ){
2455 }
2456 }
2458 /* If the IPK constraint is a REPLACE, run it last */
2464 }
2466 /* Recheck all uniqueness constraints after replace triggers have run */
2476 }
2482 }
2484 }
2486 /* Generate the table record */
2493 }
2494 }
2498 }
2500 #ifdef SQLITE_ENABLE_NULL_TRIM
2501 /*
2502 ** Change the P5 operand on the last opcode (which should be an OP_MakeRecord)
2503 ** to be the number of columns in table pTab that must not be NULL-trimmed.
2504 **
2505 ** Or if no columns of pTab may be NULL-trimmed, leave P5 at zero.
2506 */
2508 u16 i;
2510 /* Records with omitted columns are only allowed for schema format
2511 ** version 2 and later (SQLite version 3.1.4, 2005-02-20). */
2517 }
2519 }
2520 #endif
2522 /*
2523 ** Table pTab is a WITHOUT ROWID table that is being written to. The cursor
2524 ** number is iCur, and register regData contains the new record for the
2525 ** PK index. This function adds code to invoke the pre-update hook,
2526 ** if one is registered.
2527 */
2528 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
2534 ){
2543 }
2544 #else
2545 # define codeWithoutRowidPreupdate(a,b,c,d)
2546 #endif
2548 /*
2549 ** This routine generates code to finish the INSERT or UPDATE operation
2550 ** that was started by a prior call to sqlite3GenerateConstraintChecks.
2551 ** A consecutive range of registers starting at regNewData contains the
2552 ** rowid and the content to be inserted.
2553 **
2554 ** The arguments to this routine should be the same as the first six
2555 ** arguments to sqlite3GenerateConstraintChecks.
2556 */
2567 ){
2576 );
2582 /* All REPLACE indexes are at the end of the list */
2590 }
2597 }
2598 }
2603 }
2610 }
2613 }
2616 }
2620 }
2622 }
2624 /*
2625 ** Allocate cursors for the pTab table and all its indices and generate
2626 ** code to open and initialized those cursors.
2627 **
2628 ** The cursor for the object that contains the complete data (normally
2629 ** the table itself, but the PRIMARY KEY index in the case of a WITHOUT
2630 ** ROWID table) is returned in *piDataCur. The first index cursor is
2631 ** returned in *piIdxCur. The number of indices is returned.
2632 **
2633 ** Use iBase as the first cursor (either the *piDataCur for rowid tables
2634 ** or the first index for WITHOUT ROWID tables) if it is non-negative.
2635 ** If iBase is negative, then allocate the next available cursor.
2636 **
2637 ** For a rowid table, *piDataCur will be exactly one less than *piIdxCur.
2638 ** For a WITHOUT ROWID table, *piDataCur will be somewhere in the range
2639 ** of *piIdxCurs, depending on where the PRIMARY KEY index appears on the
2640 ** pTab->pIndex list.
2641 **
2642 ** If pTab is a virtual table, then this routine is a no-op and the
2643 ** *piDataCur and *piIdxCur values are left uninitialized.
2644 */
2654 ){
2666 /* This routine is a no-op for virtual tables. Leave the output
2667 ** variables *piDataCur and *piIdxCur set to illegal cursor numbers
2668 ** for improved error detection. */
2671 }
2682 }
2690 }
2696 }
2697 }
2700 }
2703 #ifdef SQLITE_TEST
2704 /*
2705 ** The following global variable is incremented whenever the
2706 ** transfer optimization is used. This is used for testing
2707 ** purposes only - to make sure the transfer optimization really
2708 ** is happening when it is supposed to.
2709 */
2714 #ifndef SQLITE_OMIT_XFER_OPT
2715 /*
2716 ** Check to see if index pSrc is compatible as a source of data
2717 ** for index pDest in an insert transfer optimization. The rules
2718 ** for a compatible index:
2719 **
2720 ** * The index is over the same set of columns
2721 ** * The same DESC and ASC markings occurs on all columns
2722 ** * The same onError processing (OE_Abort, OE_Ignore, etc)
2723 ** * The same collating sequence on each column
2724 ** * The index has the exact same WHERE clause
2725 */
2732 }
2735 }
2739 }
2745 }
2746 }
2749 }
2752 }
2753 }
2756 }
2758 /* If no test above fails then the indices must be compatible */
2760 }
2762 /*
2763 ** Attempt the transfer optimization on INSERTs of the form
2764 **
2765 ** INSERT INTO tab1 SELECT * FROM tab2;
2766 **
2767 ** The xfer optimization transfers raw records from tab2 over to tab1.
2768 ** Columns are not decoded and reassembled, which greatly improves
2769 ** performance. Raw index records are transferred in the same way.
2770 **
2771 ** The xfer optimization is only attempted if tab1 and tab2 are compatible.
2772 ** There are lots of rules for determining compatibility - see comments
2773 ** embedded in the code for details.
2774 **
2775 ** This routine returns TRUE if the optimization is guaranteed to be used.
2776 ** Sometimes the xfer optimization will only work if the destination table
2777 ** is empty - a factor that can only be determined at run-time. In that
2778 ** case, this routine generates code for the xfer optimization but also
2779 ** does a test to see if the destination table is empty and jumps over the
2780 ** xfer optimization code if the test fails. In that case, this routine
2781 ** returns FALSE so that the caller will know to go ahead and generate
2782 ** an unoptimized transfer. This routine also returns FALSE if there
2783 ** is no chance that the xfer optimization can be applied.
2784 **
2785 ** This optimization is particularly useful at making VACUUM run faster.
2786 */
2793 ){
2812 /* Do not attempt to process this query if there are an WITH clauses
2813 ** attached to it. Proceeding may generate a false "no such table: xxx"
2814 ** error if pSelect reads from a CTE named "xxx". */
2816 }
2817 #ifndef SQLITE_OMIT_VIRTUALTABLE
2820 }
2821 #endif
2825 }
2829 }
2832 }
2835 }
2838 }
2839 /* Do not need to test for a HAVING clause. If HAVING is present but
2840 ** there is no ORDER BY, we will get an error. */
2843 }
2846 }
2849 }
2852 }
2857 }
2861 }
2863 /* At this point we have established that the statement is of the
2864 ** correct syntactic form to participate in this optimization. Now
2865 ** we have to check the semantics.
2866 */
2871 }
2875 }
2878 }
2881 }
2884 }
2887 }
2890 }
2894 #ifdef SQLITE_ENABLE_HIDDEN_COLUMNS
2897 ){
2899 }
2900 #endif
2901 #ifndef SQLITE_OMIT_GENERATED_COLUMNS
2902 /* Even if tables t1 and t2 have identical schemas, if they contain
2903 ** generated columns, then this statement is semantically incorrect:
2904 **
2905 ** INSERT INTO t2 SELECT * FROM t1;
2906 **
2907 ** The reason is that generated column values are returned by the
2908 ** the SELECT statement on the right but the INSERT statement on the
2909 ** left wants them to be omitted.
2910 **
2911 ** Nevertheless, this is a useful notational shorthand to tell SQLite
2912 ** to do a bulk transfer all of the content from t1 over to t2.
2913 **
2914 ** We could, in theory, disable this (except for internal use by the
2915 ** VACUUM command where it is actually needed). But why do that? It
2916 ** seems harmless enough, and provides a useful service.
2917 */
2921 }
2922 /* But the transfer is only allowed if both the source and destination
2923 ** tables have the exact same expressions for generated columns.
2924 ** This requirement could be relaxed for VIRTUAL columns, I suppose.
2925 */
2933 }
2934 }
2935 #endif
2938 }
2942 }
2945 }
2946 /* Default values for second and subsequent columns need to match. */
2957 ){
2959 }
2960 }
2961 }
2965 }
2968 }
2971 }
2974 /* The sqlite3FaultSim() call allows this corruption test to be
2975 ** bypassed during testing, in order to exercise other corruption tests
2976 ** further downstream. */
2978 }
2979 }
2980 #ifndef SQLITE_OMIT_CHECK
2983 }
2984 #endif
2985 #ifndef SQLITE_OMIT_FOREIGN_KEY
2986 /* Disallow the transfer optimization if the destination table contains
2987 ** any foreign key constraints. This is more restrictive than necessary.
2988 ** But the main beneficiary of the transfer optimization is the VACUUM
2989 ** command, and the VACUUM command disables foreign key constraints. So
2990 ** the extra complication to make this rule less restrictive is probably
2991 ** not worth the effort. Ticket [6284df89debdfa61db8073e062908af0c9b6118e]
2992 */
2996 }
2997 #endif
3000 }
3002 /* If we get this far, it means that the xfer optimization is at
3003 ** least a possibility, though it might only work if the destination
3004 ** table (tab1) is initially empty.
3005 */
3006 #ifdef SQLITE_TEST
3007 sqlite3_xferopt_count++;
3008 #endif
3024 )){
3025 /* In some circumstances, we are able to run the xfer optimization
3026 ** only if the destination table is initially empty. Unless the
3027 ** DBFLAG_Vacuum flag is set, this block generates code to make
3028 ** that determination. If DBFLAG_Vacuum is set, then the destination
3029 ** table is always empty.
3030 **
3031 ** Conditions under which the destination must be empty:
3032 **
3033 ** (1) There is no INTEGER PRIMARY KEY but there are indices.
3034 ** (If the destination is not initially empty, the rowid fields
3035 ** of index entries might need to change.)
3036 **
3037 ** (2) The destination has a unique index. (The xfer optimization
3038 ** is unable to test uniqueness.)
3039 **
3040 ** (3) onError is something other than OE_Abort and OE_Rollback.
3041 */
3045 }
3047 u8 insFlags;
3058 }
3065 }
3072 }
3073 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
3078 #endif
3079 {
3081 }
3085 }
3094 }
3099 }
3110 /* This INSERT command is part of a VACUUM operation, which guarantees
3111 ** that the destination table is empty. If all indexed columns use
3112 ** collation sequence BINARY, then it can also be assumed that the
3113 ** index will be populated by inserting keys in strictly sorted
3114 ** order. In this case, instead of seeking within the b-tree as part
3115 ** of every OP_IdxInsert opcode, an OP_SeekEnd is added before the
3116 ** OP_IdxInsert to seek to the point within the b-tree where each key
3117 ** should be inserted. This is faster.
3118 **
3119 ** If any of the indexed columns use a collation sequence other than
3120 ** BINARY, this optimization is disabled. This is because the user
3121 ** might change the definition of a collation sequence and then run
3122 ** a VACUUM command. In that case keys may not be written in strictly
3123 ** sorted order. */
3127 }
3132 }
3135 }
3141 ){
3143 }
3144 }
3151 }
3163 }
3164 }