| blob | 072386e6560c2aa00017dda6413d6a3df7bcb61c |
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)
580 /*
581 ** If argument pVal is a Select object returned by an sqlite3MultiValues()
582 ** that was able to use the co-routine optimization, finish coding the
583 ** co-routine.
584 */
590 }
591 }
593 /*
594 ** Return true if all expressions in the expression-list passed as the
595 ** only argument are constant.
596 */
601 }
603 }
605 /*
606 ** Return true if all expressions in the expression-list passed as the
607 ** only argument are both constant and have no affinity.
608 */
617 }
620 }
622 /*
623 ** This function is called by the parser for the second and subsequent
624 ** rows of a multi-row VALUES clause. Argument pLeft is the part of
625 ** the VALUES clause already parsed, argument pRow is the vector of values
626 ** for the new row. The Select object returned represents the complete
627 ** VALUES clause, including the new row.
628 **
629 ** There are two ways in which this may be achieved - by incremental
630 ** coding of a co-routine (the "co-routine" method) or by returning a
631 ** Select object equivalent to the following (the "UNION ALL" method):
632 **
633 ** "pLeft UNION ALL SELECT pRow"
634 **
635 ** If the VALUES clause contains a lot of rows, this compound Select
636 ** object may consume a lot of memory.
637 **
638 ** When the co-routine method is used, each row that will be returned
639 ** by the VALUES clause is coded into part of a co-routine as it is
640 ** passed to this function. The returned Select object is equivalent to:
641 **
642 ** SELECT * FROM (
643 ** Select object to read co-routine
644 ** )
645 **
646 ** The co-routine method is used in most cases. Exceptions are:
647 **
648 ** a) If the current statement has a WITH clause. This is to avoid
649 ** statements like:
650 **
651 ** WITH cte AS ( VALUES('x'), ('y') ... )
652 ** SELECT * FROM cte AS a, cte AS b;
653 **
654 ** This will not work, as the co-routine uses a hard-coded register
655 ** for its OP_Yield instructions, and so it is not possible for two
656 ** cursors to iterate through it concurrently.
657 **
658 ** b) The schema is currently being parsed (i.e. the VALUES clause is part
659 ** of a schema item like a VIEW or TRIGGER). In this case there is no VM
660 ** being generated when parsing is taking place, and so generating
661 ** a co-routine is not possible.
662 **
663 ** c) There are non-constant expressions in the VALUES clause (e.g.
664 ** the VALUES clause is part of a correlated sub-query).
665 **
666 ** d) One or more of the values in the first row of the VALUES clause
667 ** has an affinity (i.e. is a CAST expression). This causes problems
668 ** because the complex rules SQLite uses (see function
669 ** sqlite3SubqueryColumnTypes() in select.c) to determine the effective
670 ** affinity of such a column for all rows require access to all values in
671 ** the column simultaneously.
672 */
680 || IN_SPECIAL_PARSE
681 ){
682 /* The co-routine method cannot be used. Fall back to UNION ALL. */
689 /* In this case set the SF_MultiValue flag only if it was set on pLeft */
691 }
698 }
703 /* Co-routine has not yet been started and the special Select object
704 ** that accesses the co-routine has not yet been created. This block
705 ** does both those things. */
709 /* Ensure the database schema has been read. This is to ensure we have
710 ** the correct text encoding. */
713 }
716 SelectDest dest;
734 /* Allocate registers for the output of the co-routine. Do so so
735 ** that there are two unused registers immediately before those
736 ** used by the co-routine. This allows the code in sqlite3Insert()
737 ** to use these registers directly, instead of copying the output
738 ** of the co-routine to a separate array for processing. */
748 }
753 }
762 }
763 }
765 }
768 }
770 /* Forward declaration */
777 );
779 /*
780 ** This routine is called to handle SQL of the following forms:
781 **
782 ** insert into TABLE (IDLIST) values(EXPRLIST),(EXPRLIST),...
783 ** insert into TABLE (IDLIST) select
784 ** insert into TABLE (IDLIST) default values
785 **
786 ** The IDLIST following the table name is always optional. If omitted,
787 ** then a list of all (non-hidden) columns for the table is substituted.
788 ** The IDLIST appears in the pColumn parameter. pColumn is NULL if IDLIST
789 ** is omitted.
790 **
791 ** For the pSelect parameter holds the values to be inserted for the
792 ** first two forms shown above. A VALUES clause is really just short-hand
793 ** for a SELECT statement that omits the FROM clause and everything else
794 ** that follows. If the pSelect parameter is NULL, that means that the
795 ** DEFAULT VALUES form of the INSERT statement is intended.
796 **
797 ** The code generated follows one of four templates. For a simple
798 ** insert with data coming from a single-row VALUES clause, the code executes
799 ** once straight down through. Pseudo-code follows (we call this
800 ** the "1st template"):
801 **
802 ** open write cursor to <table> and its indices
803 ** put VALUES clause expressions into registers
804 ** write the resulting record into <table>
805 ** cleanup
806 **
807 ** The three remaining templates assume the statement is of the form
808 **
809 ** INSERT INTO <table> SELECT ...
810 **
811 ** If the SELECT clause is of the restricted form "SELECT * FROM <table2>" -
812 ** in other words if the SELECT pulls all columns from a single table
813 ** and there is no WHERE or LIMIT or GROUP BY or ORDER BY clauses, and
814 ** if <table2> and <table1> are distinct tables but have identical
815 ** schemas, including all the same indices, then a special optimization
816 ** is invoked that copies raw records from <table2> over to <table1>.
817 ** See the xferOptimization() function for the implementation of this
818 ** template. This is the 2nd template.
819 **
820 ** open a write cursor to <table>
821 ** open read cursor on <table2>
822 ** transfer all records in <table2> over to <table>
823 ** close cursors
824 ** foreach index on <table>
825 ** open a write cursor on the <table> index
826 ** open a read cursor on the corresponding <table2> index
827 ** transfer all records from the read to the write cursors
828 ** close cursors
829 ** end foreach
830 **
831 ** The 3rd template is for when the second template does not apply
832 ** and the SELECT clause does not read from <table> at any time.
833 ** The generated code follows this template:
834 **
835 ** X <- A
836 ** goto B
837 ** A: setup for the SELECT
838 ** loop over the rows in the SELECT
839 ** load values into registers R..R+n
840 ** yield X
841 ** end loop
842 ** cleanup after the SELECT
843 ** end-coroutine X
844 ** B: open write cursor to <table> and its indices
845 ** C: yield X, at EOF goto D
846 ** insert the select result into <table> from R..R+n
847 ** goto C
848 ** D: cleanup
849 **
850 ** The 4th template is used if the insert statement takes its
851 ** values from a SELECT but the data is being inserted into a table
852 ** that is also read as part of the SELECT. In the third form,
853 ** we have to use an intermediate table to store the results of
854 ** the select. The template is like this:
855 **
856 ** X <- A
857 ** goto B
858 ** A: setup for the SELECT
859 ** loop over the tables in the SELECT
860 ** load value into register R..R+n
861 ** yield X
862 ** end loop
863 ** cleanup after the SELECT
864 ** end co-routine R
865 ** B: open temp table
866 ** L: yield X, at EOF goto M
867 ** insert row from R..R+n into temp table
868 ** goto L
869 ** M: open write cursor to <table> and its indices
870 ** rewind temp table
871 ** C: loop over rows of intermediate table
872 ** transfer values form intermediate table into <table>
873 ** end loop
874 ** D: cleanup
875 */
883 ){
907 /* Register allocations */
916 #ifndef SQLITE_OMIT_TRIGGER
920 #endif
926 }
930 /* If the Select object is really just a simple VALUES() list with a
931 ** single row (the common case) then keep that one row of values
932 ** and discard the other (unused) parts of the pSelect object
933 */
939 }
941 /* Locate the table into which we will be inserting new information.
942 */
947 }
953 }
956 /* Figure out if we have any triggers and if the table being
957 ** inserted into is a view
958 */
959 #ifndef SQLITE_OMIT_TRIGGER
962 #else
963 # define pTrigger 0
964 # define tmask 0
965 # define isView 0
966 #endif
967 #ifdef SQLITE_OMIT_VIEW
968 # undef isView
969 # define isView 0
970 #endif
973 #if TREETRACE_ENABLED
978 }
979 #endif
981 /* If pTab is really a view, make sure it has been initialized.
982 ** ViewGetColumnNames() is a no-op if pTab is not a view.
983 */
986 }
988 /* Cannot insert into a read-only table.
989 */
992 }
994 /* Allocate a VDBE
995 */
1001 #ifndef SQLITE_OMIT_XFER_OPT
1002 /* If the statement is of the form
1003 **
1004 ** INSERT INTO <table1> SELECT * FROM <table2>;
1005 **
1006 ** Then special optimizations can be applied that make the transfer
1007 ** very fast and which reduce fragmentation of indices.
1008 **
1009 ** This is the 2nd template.
1010 */
1015 ){
1019 }
1022 /* If this is an AUTOINCREMENT table, look up the sequence number in the
1023 ** sqlite_sequence table and store it in memory cell regAutoinc.
1024 */
1027 /* Allocate a block registers to hold the rowid and the values
1028 ** for all columns of the new row.
1029 */
1033 regRowid++;
1035 }
1038 /* If the INSERT statement included an IDLIST term, then make sure
1039 ** all elements of the IDLIST really are columns of the table and
1040 ** remember the column indices.
1041 **
1042 ** If the table has an INTEGER PRIMARY KEY column and that column
1043 ** is named in the IDLIST, then record in the ipkColumn variable
1044 ** the index into IDLIST of the primary key column. ipkColumn is
1045 ** the index of the primary key as it appears in IDLIST, not as
1046 ** is appears in the original table. (The index of the INTEGER
1047 ** PRIMARY KEY in the original table is pTab->iPKey.) After this
1048 ** loop, if ipkColumn==(-1), that means that integer primary key
1049 ** is unspecified, and hence the table is either WITHOUT ROWID or
1050 ** it will automatically generated an integer primary key.
1051 **
1052 ** bIdListInOrder is true if the columns in IDLIST are in storage
1053 ** order. This enables an optimization that avoids shuffling the
1054 ** columns into storage order. False negatives are harmless,
1055 ** but false positives will cause database corruption.
1056 */
1063 }
1071 }
1072 #ifndef SQLITE_OMIT_GENERATED_COLUMNS
1078 }
1079 #endif
1081 }
1082 }
1092 }
1093 }
1094 }
1095 }
1097 /* Figure out how many columns of data are supplied. If the data
1098 ** is coming from a SELECT statement, then generate a co-routine that
1099 ** produces a single row of the SELECT on each invocation. The
1100 ** co-routine is the common header to the 3rd and 4th templates.
1101 */
1103 /* Data is coming from a SELECT or from a multi-row VALUES clause.
1104 ** Generate a co-routine to run the SELECT. */
1110 ){
1120 }
1138 }
1140 /* Set useTempTable to TRUE if the result of the SELECT statement
1141 ** should be written into a temporary table (template 4). Set to
1142 ** FALSE if each output row of the SELECT can be written directly into
1143 ** the destination table (template 3).
1144 **
1145 ** A temp table must be used if the table being updated is also one
1146 ** of the tables being read by the SELECT statement. Also use a
1147 ** temp table in the case of row triggers.
1148 */
1151 }
1154 /* Invoke the coroutine to extract information from the SELECT
1155 ** and add it to a transient table srcTab. The code generated
1156 ** here is from the 4th template:
1157 **
1158 ** B: open temp table
1159 ** L: yield X, goto M at EOF
1160 ** insert row from R..R+n into temp table
1161 ** goto L
1162 ** M: ...
1163 */
1180 }
1182 /* This is the case if the data for the INSERT is coming from a
1183 ** single-row VALUES clause
1184 */
1185 NameContext sNC;
1194 }
1197 }
1198 }
1200 /* If there is no IDLIST term but the table has an integer primary
1201 ** key, the set the ipkColumn variable to the integer primary key
1202 ** column index in the original table definition.
1203 */
1206 #ifndef SQLITE_OMIT_GENERATED_COLUMNS
1214 ipkColumn--;
1215 }
1216 }
1217 }
1218 #endif
1220 /* Make sure the number of columns in the source data matches the number
1221 ** of columns to be inserted into the table.
1222 */
1229 }
1230 }
1236 }
1237 }
1241 }
1243 /* Initialize the count of rows to be inserted
1244 */
1249 ){
1252 }
1254 /* If this is not a view, open the table and and all indices */
1262 }
1267 }
1269 }
1270 #ifndef SQLITE_OMIT_UPSERT
1277 }
1281 }
1284 }
1295 }
1296 }
1299 }
1300 #endif
1303 /* This is the top of the main insertion loop */
1305 /* This block codes the top of loop only. The complete loop is the
1306 ** following pseudocode (template 4):
1307 **
1308 ** rewind temp table, if empty goto D
1309 ** C: loop over rows of intermediate table
1310 ** transfer values form intermediate table into <table>
1311 ** end loop
1312 ** D: ...
1313 */
1317 /* This block codes the top of loop only. The complete loop is the
1318 ** following pseudocode (template 3):
1319 **
1320 ** C: yield X, at EOF goto D
1321 ** insert the select result into <table> from R..R+n
1322 ** goto C
1323 ** D: ...
1324 */
1329 /* tag-20191021-001: If the INTEGER PRIMARY KEY is being generated by the
1330 ** SELECT, go ahead and copy the value into the rowid slot now, so that
1331 ** the value does not get overwritten by a NULL at tag-20191021-002. */
1333 }
1334 }
1336 /* Compute data for ordinary columns of the new entry. Values
1337 ** are written in storage order into registers starting with regData.
1338 ** Only ordinary columns are computed in this loop. The rowid
1339 ** (if there is one) is computed later and generated columns are
1340 ** computed after the rowid since they might depend on the value
1341 ** of the rowid.
1342 */
1347 u32 colFlags;
1350 /* tag-20191021-002: References to the INTEGER PRIMARY KEY are filled
1351 ** using the rowid. So put a NULL in the IPK slot of the record to avoid
1352 ** using excess space. The file format definition requires this extra
1353 ** NULL - we cannot optimize further by skipping the column completely */
1356 }
1358 nHidden++;
1360 /* Virtual columns do not participate in OP_MakeRecord. So back up
1361 ** iRegStore by one slot to compensate for the iRegStore++ in the
1362 ** outer for() loop */
1363 iRegStore--;
1366 /* Stored columns are computed later. But if there are BEFORE
1367 ** triggers, the slots used for stored columns will be OP_Copy-ed
1368 ** to a second block of registers, so the register needs to be
1369 ** initialized to NULL to avoid an uninitialized register read */
1372 }
1375 /* Hidden columns that are not explicitly named in the INSERT
1376 ** get there default value */
1379 iRegStore);
1381 }
1382 }
1387 /* A column not named in the insert column list gets its
1388 ** default value */
1391 iRegStore);
1393 }
1396 /* This is INSERT INTO ... DEFAULT VALUES. Load the default value. */
1399 iRegStore);
1403 }
1410 }
1417 }
1418 }
1419 }
1422 /* Run the BEFORE and INSTEAD OF triggers, if there are any
1423 */
1428 /* build the NEW.* reference row. Note that if there is an INTEGER
1429 ** PRIMARY KEY into which a NULL is being inserted, that NULL will be
1430 ** translated into a unique ID for the row. But on a BEFORE trigger,
1431 ** we do not know what the unique ID will be (because the insert has
1432 ** not happened yet) so we substitute a rowid of -1
1433 */
1444 }
1449 }
1451 /* Copy the new data already generated. */
1455 #ifndef SQLITE_OMIT_GENERATED_COLUMNS
1456 /* Compute the new value for generated columns after all other
1457 ** columns have already been computed. This must be done after
1458 ** computing the ROWID in case one of the generated columns
1459 ** refers to the ROWID. */
1464 }
1465 #endif
1467 /* If this is an INSERT on a view with an INSTEAD OF INSERT trigger,
1468 ** do not attempt any conversions before assembling the record.
1469 ** If this is a real table, attempt conversions as required by the
1470 ** table column affinities.
1471 */
1474 }
1476 /* Fire BEFORE or INSTEAD OF triggers */
1481 }
1485 /* The row that the VUpdate opcode will delete: none */
1487 }
1489 /* Compute the new rowid */
1493 /* Rowid already initialized at tag-20191021-001 */
1501 }
1502 }
1503 /* If the PRIMARY KEY expression is NULL, then use OP_NewRowid
1504 ** to generate a unique primary key value.
1505 */
1515 }
1517 }
1523 }
1526 #ifndef SQLITE_OMIT_GENERATED_COLUMNS
1527 /* Compute the new value for generated columns after all other
1528 ** columns have already been computed. This must be done after
1529 ** computing the ROWID in case one of the generated columns
1530 ** is derived from the INTEGER PRIMARY KEY. */
1533 }
1534 #endif
1536 /* Generate code to check constraints and generate index keys and
1537 ** do the insertion.
1538 */
1539 #ifndef SQLITE_OMIT_VIRTUALTABLE
1547 #endif
1548 {
1553 );
1556 }
1558 /* Set the OPFLAG_USESEEKRESULT flag if either (a) there are no REPLACE
1559 ** constraints or (b) there are no triggers and this table is not a
1560 ** parent table in a foreign key constraint. It is safe to set the
1561 ** flag in the second case as if any REPLACE constraint is hit, an
1562 ** OP_Delete or OP_IdxDelete instruction will be executed on each
1563 ** cursor that is disturbed. And these instructions both clear the
1564 ** VdbeCursor.seekResult variable, disabling the OPFLAG_USESEEKRESULT
1565 ** functionality. */
1569 );
1570 }
1571 #ifdef SQLITE_ALLOW_ROWID_IN_VIEW
1573 /* If there is a RETURNING clause, populate the rowid register with
1574 ** constant value -1, in case one or more of the returned expressions
1575 ** refer to the "rowid" of the view. */
1577 #endif
1578 }
1580 /* Update the count of rows that are inserted
1581 */
1584 }
1587 /* Code AFTER triggers */
1590 }
1592 /* The bottom of the main insertion loop, if the data source
1593 ** is a SELECT statement.
1594 */
1602 #ifdef SQLITE_DEBUG
1603 /* If we are jumping back to an OP_Yield that is preceded by an
1604 ** OP_ReleaseReg, set the p5 flag on the OP_Goto so that the
1605 ** OP_ReleaseReg will be included in the loop. */
1609 }
1610 #endif
1612 }
1614 #ifndef SQLITE_OMIT_XFER_OPT
1615 insert_end:
1617 /* Update the sqlite_sequence table by storing the content of the
1618 ** maximum rowid counter values recorded while inserting into
1619 ** autoincrement tables.
1620 */
1623 }
1625 /*
1626 ** Return the number of rows inserted. If this routine is
1627 ** generating code because of a call to sqlite3NestedParse(), do not
1628 ** invoke the callback function.
1629 */
1632 }
1634 insert_cleanup:
1641 }
1643 /* Make sure "isView" and other macros defined above are undefined. Otherwise
1644 ** they may interfere with compilation of other functions in this file
1645 ** (or in another file, if this file becomes part of the amalgamation). */
1646 #ifdef isView
1647 #undef isView
1648 #endif
1649 #ifdef pTrigger
1650 #undef pTrigger
1651 #endif
1652 #ifdef tmask
1653 #undef tmask
1654 #endif
1656 /*
1657 ** Meanings of bits in of pWalker->eCode for
1658 ** sqlite3ExprReferencesUpdatedColumn()
1659 */
1663 /* This is the Walker callback from sqlite3ExprReferencesUpdatedColumn().
1664 * Set bit 0x01 of pWalker->eCode if pWalker->eCode to 0 and if this
1665 ** expression node references any of the
1666 ** columns that are being modified by an UPDATE statement.
1667 */
1674 }
1677 }
1678 }
1680 }
1682 /*
1683 ** pExpr is a CHECK constraint on a row that is being UPDATE-ed. The
1684 ** only columns that are modified by the UPDATE are those for which
1685 ** aiChng[i]>=0, and also the ROWID is modified if chngRowid is true.
1686 **
1687 ** Return true if CHECK constraint pExpr uses any of the
1688 ** changing columns (or the rowid if it is changing). In other words,
1689 ** return true if this CHECK constraint must be validated for
1690 ** the new row in the UPDATE statement.
1691 **
1692 ** 2018-09-15: pExpr might also be an expression for an index-on-expressions.
1693 ** The operation of this routine is the same - return true if an only if
1694 ** the expression uses one or more of columns identified by the second and
1695 ** third arguments.
1696 */
1701 ){
1702 Walker w;
1711 }
1717 }
1719 /*
1720 ** The sqlite3GenerateConstraintChecks() routine usually wants to visit
1721 ** the indexes of a table in the order provided in the Table->pIndex list.
1722 ** However, sometimes (rarely - when there is an upsert) it wants to visit
1723 ** the indexes in a different order. The following data structures accomplish
1724 ** this.
1725 **
1726 ** The IndexIterator object is used to walk through all of the indexes
1727 ** of a table in either Index.pNext order, or in some other order established
1728 ** by an array of IndexListTerm objects.
1729 */
1744 };
1746 /* When IndexIterator.eType==1, then each index is an array of instances
1747 ** of the following object
1748 */
1752 };
1754 /* Return the first index on the list */
1763 }
1764 }
1766 /* Return the next index from the list. Return NULL when out of indexes */
1773 }
1780 }
1781 }
1783 /*
1784 ** Generate code to do constraint checks prior to an INSERT or an UPDATE
1785 ** on table pTab.
1786 **
1787 ** The regNewData parameter is the first register in a range that contains
1788 ** the data to be inserted or the data after the update. There will be
1789 ** pTab->nCol+1 registers in this range. The first register (the one
1790 ** that regNewData points to) will contain the new rowid, or NULL in the
1791 ** case of a WITHOUT ROWID table. The second register in the range will
1792 ** contain the content of the first table column. The third register will
1793 ** contain the content of the second table column. And so forth.
1794 **
1795 ** The regOldData parameter is similar to regNewData except that it contains
1796 ** the data prior to an UPDATE rather than afterwards. regOldData is zero
1797 ** for an INSERT. This routine can distinguish between UPDATE and INSERT by
1798 ** checking regOldData for zero.
1799 **
1800 ** For an UPDATE, the pkChng boolean is true if the true primary key (the
1801 ** rowid for a normal table or the PRIMARY KEY for a WITHOUT ROWID table)
1802 ** might be modified by the UPDATE. If pkChng is false, then the key of
1803 ** the iDataCur content table is guaranteed to be unchanged by the UPDATE.
1804 **
1805 ** For an INSERT, the pkChng boolean indicates whether or not the rowid
1806 ** was explicitly specified as part of the INSERT statement. If pkChng
1807 ** is zero, it means that the either rowid is computed automatically or
1808 ** that the table is a WITHOUT ROWID table and has no rowid. On an INSERT,
1809 ** pkChng will only be true if the INSERT statement provides an integer
1810 ** value for either the rowid column or its INTEGER PRIMARY KEY alias.
1811 **
1812 ** The code generated by this routine will store new index entries into
1813 ** registers identified by aRegIdx[]. No index entry is created for
1814 ** indices where aRegIdx[i]==0. The order of indices in aRegIdx[] is
1815 ** the same as the order of indices on the linked list of indices
1816 ** at pTab->pIndex.
1817 **
1818 ** (2019-05-07) The generated code also creates a new record for the
1819 ** main table, if pTab is a rowid table, and stores that record in the
1820 ** register identified by aRegIdx[nIdx] - in other words in the first
1821 ** entry of aRegIdx[] past the last index. It is important that the
1822 ** record be generated during constraint checks to avoid affinity changes
1823 ** to the register content that occur after constraint checks but before
1824 ** the new record is inserted.
1825 **
1826 ** The caller must have already opened writeable cursors on the main
1827 ** table and all applicable indices (that is to say, all indices for which
1828 ** aRegIdx[] is not zero). iDataCur is the cursor for the main table when
1829 ** inserting or updating a rowid table, or the cursor for the PRIMARY KEY
1830 ** index when operating on a WITHOUT ROWID table. iIdxCur is the cursor
1831 ** for the first index in the pTab->pIndex list. Cursors for other indices
1832 ** are at iIdxCur+N for the N-th element of the pTab->pIndex list.
1833 **
1834 ** This routine also generates code to check constraints. NOT NULL,
1835 ** CHECK, and UNIQUE constraints are all checked. If a constraint fails,
1836 ** then the appropriate action is performed. There are five possible
1837 ** actions: ROLLBACK, ABORT, FAIL, REPLACE, and IGNORE.
1838 **
1839 ** Constraint type Action What Happens
1840 ** --------------- ---------- ----------------------------------------
1841 ** any ROLLBACK The current transaction is rolled back and
1842 ** sqlite3_step() returns immediately with a
1843 ** return code of SQLITE_CONSTRAINT.
1844 **
1845 ** any ABORT Back out changes from the current command
1846 ** only (do not do a complete rollback) then
1847 ** cause sqlite3_step() to return immediately
1848 ** with SQLITE_CONSTRAINT.
1849 **
1850 ** any FAIL Sqlite3_step() returns immediately with a
1851 ** return code of SQLITE_CONSTRAINT. The
1852 ** transaction is not rolled back and any
1853 ** changes to prior rows are retained.
1854 **
1855 ** any IGNORE The attempt in insert or update the current
1856 ** row is skipped, without throwing an error.
1857 ** Processing continues with the next row.
1858 ** (There is an immediate jump to ignoreDest.)
1859 **
1860 ** NOT NULL REPLACE The NULL value is replace by the default
1861 ** value for that column. If the default value
1862 ** is NULL, the action is the same as ABORT.
1863 **
1864 ** UNIQUE REPLACE The other row that conflicts with the row
1865 ** being inserted is removed.
1866 **
1867 ** CHECK REPLACE Illegal. The results in an exception.
1868 **
1869 ** Which action to take is determined by the overrideError parameter.
1870 ** Or if overrideError==OE_Default, then the pParse->onError parameter
1871 ** is used. Or if pParse->onError==OE_Default then the onError value
1872 ** for the constraint is used.
1873 */
1888 ){
1906 /* Variables associated with retesting uniqueness constraints after
1907 ** replace triggers fire have run */
1922 /* pPk is the PRIMARY KEY index for WITHOUT ROWID tables and NULL for
1923 ** normal rowid tables. nPkField is the number of key fields in the
1924 ** pPk index or 1 for a rowid table. In other words, nPkField is the
1925 ** number of fields in the true primary key of the table. */
1932 }
1934 /* Record that this module has started */
1938 /* Test all NOT NULL constraints.
1939 */
1953 }
1956 nGenerated++;
1958 }
1960 /* Do not check NOT NULL on columns that do not change */
1962 }
1967 }
1971 ){
1978 }
1981 }
1991 nSeenReplace++;
1996 }
1999 /* no break */ deliberate_fall_through
2011 }
2017 }
2021 /* If there are no generated columns with NOT NULL constraints
2022 ** and no NOT NULL ON CONFLICT REPLACE constraints, then a single
2023 ** pass is sufficient */
2025 }
2028 #ifndef SQLITE_OMIT_GENERATED_COLUMNS
2030 /* If any NOT NULL ON CONFLICT REPLACE constraints fired on the
2031 ** first pass, recomputed values for all generated columns, as
2032 ** those values might depend on columns affected by the REPLACE.
2033 */
2035 }
2036 #endif
2040 /* Test all CHECK constraints
2041 */
2042 #ifndef SQLITE_OMIT_CHECK
2053 ){
2054 /* The check constraints do not reference any of the columns being
2055 ** updated so there is no point it verifying the check constraint */
2057 }
2061 }
2067 }
2077 P5_ConstraintCheck);
2078 }
2080 }
2082 }
2085 /* UNIQUE and PRIMARY KEY constraints should be handled in the following
2086 ** order:
2087 **
2088 ** (1) OE_Update
2089 ** (2) OE_Abort, OE_Fail, OE_Rollback, OE_Ignore
2090 ** (3) OE_Replace
2091 **
2092 ** OE_Fail and OE_Ignore must happen before any changes are made.
2093 ** OE_Update guarantees that only a single row will change, so it
2094 ** must happen before OE_Replace. Technically, OE_Abort and OE_Rollback
2095 ** could happen in any order, but they are grouped up front for
2096 ** convenience.
2097 **
2098 ** 2018-08-14: Ticket https://www.sqlite.org/src/info/908f001483982c43
2099 ** The order of constraints used to have OE_Update as (2) and OE_Abort
2100 ** and so forth as (1). But apparently PostgreSQL checks the OE_Update
2101 ** constraint before any others, so it had to be moved.
2102 **
2103 ** Constraint checking code is generated in this order:
2104 ** (A) The rowid constraint
2105 ** (B) Unique index constraints that do not have OE_Replace as their
2106 ** default conflict resolution strategy
2107 ** (C) Unique index that do use OE_Replace by default.
2108 **
2109 ** The ordering of (2) and (3) is accomplished by making sure the linked
2110 ** list of indexes attached to a table puts all OE_Replace indexes last
2111 ** in the list. See sqlite3CreateIndex() for where that happens.
2112 */
2119 /* There is just on ON CONFLICT clause and it has no constraint-target */
2122 /* A single ON CONFLICT DO NOTHING clause, without a constraint-target.
2123 ** Make all unique constraint resolution be OE_Ignore */
2127 /* A single ON CONFLICT DO UPDATE. Make all resolutions OE_Update */
2129 }
2131 /* Otherwise, we'll need to run the IndexListTerm array version of the
2132 ** iterator to ensure that all of the ON CONFLICT conditions are
2133 ** checked first and in order. */
2135 u64 nByte;
2140 }
2155 jj++;
2156 }
2161 i++;
2162 }
2167 i++;
2168 }
2170 }
2171 }
2173 /* Determine if it is possible that triggers (either explicitly coded
2174 ** triggers or FK resolution actions) might run as a result of deletes
2175 ** that happen when OE_Replace conflict resolution occurs. (Call these
2176 ** "replace triggers".) If any replace triggers run, we will need to
2177 ** recheck all of the uniqueness constraints after they have all run.
2178 ** But on the recheck, the resolution is OE_Abort instead of OE_Replace.
2179 **
2180 ** If replace triggers are a possibility, then
2181 **
2182 ** (1) Allocate register regTrigCnt and initialize it to zero.
2183 ** That register will count the number of replace triggers that
2184 ** fire. Constraint recheck only occurs if the number is positive.
2185 ** (2) Initialize pTrigger to the list of all DELETE triggers on pTab.
2186 ** (3) Initialize addrRecheck and lblRecheckOk
2187 **
2188 ** The uniqueness rechecking code will create a series of tests to run
2189 ** in a second pass. The addrRecheck and lblRecheckOk variables are
2190 ** used to link together these tests which are separated from each other
2191 ** in the generate bytecode.
2192 */
2194 /* There are not DELETE triggers nor FK constraints. No constraint
2195 ** rechecks are needed. */
2205 }
2207 /* Replace triggers might exist. Allocate the counter and
2208 ** initialize it to zero. */
2214 }
2215 }
2217 /* If rowid is changing, make sure the new rowid does not previously
2218 ** exist in the table.
2219 */
2223 /* Figure out what action to take in case of a rowid collision */
2229 }
2231 /* figure out whether or not upsert applies in this case */
2239 }
2240 }
2242 /* The first ON CONFLICT clause has a conflict target other than
2243 ** the IPK. We have to jump ahead to that first ON CONFLICT clause
2244 ** and then come back here and deal with the IPK afterwards */
2246 }
2247 }
2249 /* If the response to a rowid conflict is REPLACE but the response
2250 ** to some other UNIQUE constraint is FAIL or IGNORE, then we need
2251 ** to defer the running of the rowid conflict checking until after
2252 ** the UNIQUE constraints have run.
2253 */
2258 ){
2261 }
2264 /* pkChng!=0 does not mean that the rowid has changed, only that
2265 ** it might have changed. Skip the conflict logic below if the rowid
2266 ** is unchanged. */
2270 }
2272 /* Check to see if the new rowid already exists in the table. Skip
2273 ** the following conflict logic if it does not. */
2282 /* no break */ deliberate_fall_through
2283 }
2292 }
2294 /* If there are DELETE triggers on this table and the
2295 ** recursive-triggers flag is set, call GenerateRowDelete() to
2296 ** remove the conflicting row from the table. This will fire
2297 ** the triggers and remove both the table and index b-tree entries.
2298 **
2299 ** Otherwise, if there are no triggers or the recursive-triggers
2300 ** flag is not set, but the table has one or more indexes, call
2301 ** GenerateRowIndexDelete(). This removes the index b-tree entries
2302 ** only. The table b-tree entry will be replaced by the new entry
2303 ** when it is inserted.
2304 **
2305 ** If either GenerateRowDelete() or GenerateRowIndexDelete() is called,
2306 ** also invoke MultiWrite() to indicate that this VDBE may require
2307 ** statement rollback (if the statement is aborted after the delete
2308 ** takes place). Earlier versions called sqlite3MultiWrite() regardless,
2309 ** but being more selective here allows statements like:
2310 **
2311 ** REPLACE INTO t(rowid) VALUES($newrowid)
2312 **
2313 ** to run without a statement journal if there are no indexes on the
2314 ** table.
2315 */
2321 nReplaceTrig++;
2323 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
2325 /* This OP_Delete opcode fires the pre-update-hook only. It does
2326 ** not modify the b-tree. It is more efficient to let the coming
2327 ** OP_Insert replace the existing entry than it is to delete the
2328 ** existing entry and then insert a new one. */
2335 }
2336 }
2339 }
2340 #ifndef SQLITE_OMIT_UPSERT
2343 /* no break */ deliberate_fall_through
2344 }
2345 #endif
2350 }
2351 }
2358 }
2359 }
2361 /* Test all UNIQUE constraints by creating entries for each UNIQUE
2362 ** index and making sure that duplicate entries do not already exist.
2363 ** Compute the revised record entries for indices as we go.
2364 **
2365 ** This loop also handles the case of the PRIMARY KEY index for a
2366 ** WITHOUT ROWID table.
2367 */
2369 pIdx;
2371 ){
2383 }
2384 }
2389 }
2394 /* Skip partial indices for which the WHERE clause is not true */
2399 SQLITE_JUMPIFNULL);
2401 }
2403 /* Create a record for this index entry as it should appear after
2404 ** the insert or update. Store that record in the aRegIdx[ix] register
2405 */
2424 }
2425 }
2428 #ifdef SQLITE_ENABLE_NULL_TRIM
2431 }
2432 #endif
2435 /* In an UPDATE operation, if this index is the PRIMARY KEY index
2436 ** of a WITHOUT ROWID table and there has been no change the
2437 ** primary key, then no collision is possible. The collision detection
2438 ** logic below can all be skipped. */
2442 }
2444 /* Find out what action to take in case there is a uniqueness conflict */
2449 }
2454 }
2456 /* Figure out if the upsert clause applies to this index */
2462 }
2463 }
2465 /* Collision detection may be omitted if all of the following are true:
2466 ** (1) The conflict resolution algorithm is REPLACE
2467 ** (2) The table is a WITHOUT ROWID table
2468 ** (3) There are no secondary indexes on the table
2469 ** (4) No delete triggers need to be fired if there is a conflict
2470 ** (5) No FK constraint counters need to be updated if a conflict occurs.
2471 **
2472 ** This is not possible for ENABLE_PREUPDATE_HOOK builds, as the row
2473 ** must be explicitly deleted in order to ensure any pre-update hook
2474 ** is invoked. */
2476 #ifndef SQLITE_ENABLE_PREUPDATE_HOOK
2484 ){
2487 }
2490 /* Check to see if the new index entry will be unique */
2492 addrConflictCk =
2496 /* Generate code to handle collisions */
2501 /* Conflict only if the rowid of the existing index entry
2502 ** is different from old-rowid */
2507 }
2510 /* Extract the PRIMARY KEY from the end of the index entry and
2511 ** store it in registers regR..regR+nPk-1 */
2519 }
2520 }
2522 /* If currently processing the PRIMARY KEY of a WITHOUT ROWID
2523 ** table, only conflict if the new PRIMARY KEY values are actually
2524 ** different from the old. See TH3 withoutrowid04.test.
2525 **
2526 ** For a UNIQUE index, only conflict if the PRIMARY KEY values
2527 ** of the matched index row are different from the original PRIMARY
2528 ** KEY values of this row before the update. */
2540 }
2544 );
2548 }
2549 }
2550 }
2551 }
2553 /* Generate code that executes if the new index entry is not unique */
2565 }
2566 #ifndef SQLITE_OMIT_UPSERT
2569 /* no break */ deliberate_fall_through
2570 }
2571 #endif
2576 }
2587 nReplaceTrig++;
2588 }
2591 }
2597 }
2605 /* Here we insert code that will be invoked after all constraint
2606 ** checks have run, if and only if one or more replace triggers
2607 ** fired. */
2611 /* Bypass the recheck if this partial index is not defined
2612 ** for the current row */
2615 }
2616 /* Copy the constraint check code from above, except change
2617 ** the constraint-ok jump destination to be the address of
2618 ** the next retest block */
2621 /* The sqlite3VdbeAddOp4() call might reallocate the opcode array.
2622 ** Hence, make a complete copy of the opcode, rather than using
2623 ** a pointer to the opcode. */
2632 }
2637 }
2638 nConflictCk--;
2639 addrConflictCk++;
2640 }
2641 /* If the retest fails, issue an abort */
2645 }
2648 }
2649 }
2653 && upsertIpkReturn
2655 ){
2659 }
2660 }
2662 /* If the IPK constraint is a REPLACE, run it last */
2668 }
2670 /* Recheck all uniqueness constraints after replace triggers have run */
2680 }
2686 }
2688 }
2690 /* Generate the table record */
2697 }
2698 }
2702 }
2704 #ifdef SQLITE_ENABLE_NULL_TRIM
2705 /*
2706 ** Change the P5 operand on the last opcode (which should be an OP_MakeRecord)
2707 ** to be the number of columns in table pTab that must not be NULL-trimmed.
2708 **
2709 ** Or if no columns of pTab may be NULL-trimmed, leave P5 at zero.
2710 */
2712 u16 i;
2714 /* Records with omitted columns are only allowed for schema format
2715 ** version 2 and later (SQLite version 3.1.4, 2005-02-20). */
2721 }
2723 }
2724 #endif
2726 /*
2727 ** Table pTab is a WITHOUT ROWID table that is being written to. The cursor
2728 ** number is iCur, and register regData contains the new record for the
2729 ** PK index. This function adds code to invoke the pre-update hook,
2730 ** if one is registered.
2731 */
2732 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
2738 ){
2747 }
2748 #else
2749 # define codeWithoutRowidPreupdate(a,b,c,d)
2750 #endif
2752 /*
2753 ** This routine generates code to finish the INSERT or UPDATE operation
2754 ** that was started by a prior call to sqlite3GenerateConstraintChecks.
2755 ** A consecutive range of registers starting at regNewData contains the
2756 ** rowid and the content to be inserted.
2757 **
2758 ** The arguments to this routine should be the same as the first six
2759 ** arguments to sqlite3GenerateConstraintChecks.
2760 */
2771 ){
2780 );
2786 /* All REPLACE indexes are at the end of the list */
2794 }
2801 }
2802 }
2807 }
2814 }
2817 }
2820 }
2824 }
2826 }
2828 /*
2829 ** Allocate cursors for the pTab table and all its indices and generate
2830 ** code to open and initialized those cursors.
2831 **
2832 ** The cursor for the object that contains the complete data (normally
2833 ** the table itself, but the PRIMARY KEY index in the case of a WITHOUT
2834 ** ROWID table) is returned in *piDataCur. The first index cursor is
2835 ** returned in *piIdxCur. The number of indices is returned.
2836 **
2837 ** Use iBase as the first cursor (either the *piDataCur for rowid tables
2838 ** or the first index for WITHOUT ROWID tables) if it is non-negative.
2839 ** If iBase is negative, then allocate the next available cursor.
2840 **
2841 ** For a rowid table, *piDataCur will be exactly one less than *piIdxCur.
2842 ** For a WITHOUT ROWID table, *piDataCur will be somewhere in the range
2843 ** of *piIdxCurs, depending on where the PRIMARY KEY index appears on the
2844 ** pTab->pIndex list.
2845 **
2846 ** If pTab is a virtual table, then this routine is a no-op and the
2847 ** *piDataCur and *piIdxCur values are left uninitialized.
2848 */
2858 ){
2870 /* This routine is a no-op for virtual tables. Leave the output
2871 ** variables *piDataCur and *piIdxCur set to illegal cursor numbers
2872 ** for improved error detection. */
2875 }
2886 }
2894 }
2900 }
2901 }
2904 }
2907 #ifdef SQLITE_TEST
2908 /*
2909 ** The following global variable is incremented whenever the
2910 ** transfer optimization is used. This is used for testing
2911 ** purposes only - to make sure the transfer optimization really
2912 ** is happening when it is supposed to.
2913 */
2918 #ifndef SQLITE_OMIT_XFER_OPT
2919 /*
2920 ** Check to see if index pSrc is compatible as a source of data
2921 ** for index pDest in an insert transfer optimization. The rules
2922 ** for a compatible index:
2923 **
2924 ** * The index is over the same set of columns
2925 ** * The same DESC and ASC markings occurs on all columns
2926 ** * The same onError processing (OE_Abort, OE_Ignore, etc)
2927 ** * The same collating sequence on each column
2928 ** * The index has the exact same WHERE clause
2929 */
2936 }
2939 }
2943 }
2949 }
2950 }
2953 }
2956 }
2957 }
2960 }
2962 /* If no test above fails then the indices must be compatible */
2964 }
2966 /*
2967 ** Attempt the transfer optimization on INSERTs of the form
2968 **
2969 ** INSERT INTO tab1 SELECT * FROM tab2;
2970 **
2971 ** The xfer optimization transfers raw records from tab2 over to tab1.
2972 ** Columns are not decoded and reassembled, which greatly improves
2973 ** performance. Raw index records are transferred in the same way.
2974 **
2975 ** The xfer optimization is only attempted if tab1 and tab2 are compatible.
2976 ** There are lots of rules for determining compatibility - see comments
2977 ** embedded in the code for details.
2978 **
2979 ** This routine returns TRUE if the optimization is guaranteed to be used.
2980 ** Sometimes the xfer optimization will only work if the destination table
2981 ** is empty - a factor that can only be determined at run-time. In that
2982 ** case, this routine generates code for the xfer optimization but also
2983 ** does a test to see if the destination table is empty and jumps over the
2984 ** xfer optimization code if the test fails. In that case, this routine
2985 ** returns FALSE so that the caller will know to go ahead and generate
2986 ** an unoptimized transfer. This routine also returns FALSE if there
2987 ** is no chance that the xfer optimization can be applied.
2988 **
2989 ** This optimization is particularly useful at making VACUUM run faster.
2990 */
2997 ){
3016 /* Do not attempt to process this query if there are an WITH clauses
3017 ** attached to it. Proceeding may generate a false "no such table: xxx"
3018 ** error if pSelect reads from a CTE named "xxx". */
3020 }
3021 #ifndef SQLITE_OMIT_VIRTUALTABLE
3024 }
3025 #endif
3029 }
3033 }
3036 }
3039 }
3042 }
3043 /* Do not need to test for a HAVING clause. If HAVING is present but
3044 ** there is no ORDER BY, we will get an error. */
3047 }
3050 }
3053 }
3056 }
3061 }
3065 }
3067 /* At this point we have established that the statement is of the
3068 ** correct syntactic form to participate in this optimization. Now
3069 ** we have to check the semantics.
3070 */
3075 }
3079 }
3082 }
3085 }
3088 }
3091 }
3094 }
3098 #ifdef SQLITE_ENABLE_HIDDEN_COLUMNS
3101 ){
3103 }
3104 #endif
3105 #ifndef SQLITE_OMIT_GENERATED_COLUMNS
3106 /* Even if tables t1 and t2 have identical schemas, if they contain
3107 ** generated columns, then this statement is semantically incorrect:
3108 **
3109 ** INSERT INTO t2 SELECT * FROM t1;
3110 **
3111 ** The reason is that generated column values are returned by the
3112 ** the SELECT statement on the right but the INSERT statement on the
3113 ** left wants them to be omitted.
3114 **
3115 ** Nevertheless, this is a useful notational shorthand to tell SQLite
3116 ** to do a bulk transfer all of the content from t1 over to t2.
3117 **
3118 ** We could, in theory, disable this (except for internal use by the
3119 ** VACUUM command where it is actually needed). But why do that? It
3120 ** seems harmless enough, and provides a useful service.
3121 */
3125 }
3126 /* But the transfer is only allowed if both the source and destination
3127 ** tables have the exact same expressions for generated columns.
3128 ** This requirement could be relaxed for VIRTUAL columns, I suppose.
3129 */
3137 }
3138 }
3139 #endif
3142 }
3146 }
3149 }
3150 /* Default values for second and subsequent columns need to match. */
3161 ){
3163 }
3164 }
3165 }
3169 }
3172 }
3175 }
3178 /* The sqlite3FaultSim() call allows this corruption test to be
3179 ** bypassed during testing, in order to exercise other corruption tests
3180 ** further downstream. */
3182 }
3183 }
3184 #ifndef SQLITE_OMIT_CHECK
3188 ){
3190 }
3191 #endif
3192 #ifndef SQLITE_OMIT_FOREIGN_KEY
3193 /* Disallow the transfer optimization if the destination table contains
3194 ** any foreign key constraints. This is more restrictive than necessary.
3195 ** But the main beneficiary of the transfer optimization is the VACUUM
3196 ** command, and the VACUUM command disables foreign key constraints. So
3197 ** the extra complication to make this rule less restrictive is probably
3198 ** not worth the effort. Ticket [6284df89debdfa61db8073e062908af0c9b6118e]
3199 */
3203 }
3204 #endif
3207 }
3209 /* If we get this far, it means that the xfer optimization is at
3210 ** least a possibility, though it might only work if the destination
3211 ** table (tab1) is initially empty.
3212 */
3213 #ifdef SQLITE_TEST
3214 sqlite3_xferopt_count++;
3215 #endif
3231 )){
3232 /* In some circumstances, we are able to run the xfer optimization
3233 ** only if the destination table is initially empty. Unless the
3234 ** DBFLAG_Vacuum flag is set, this block generates code to make
3235 ** that determination. If DBFLAG_Vacuum is set, then the destination
3236 ** table is always empty.
3237 **
3238 ** Conditions under which the destination must be empty:
3239 **
3240 ** (1) There is no INTEGER PRIMARY KEY but there are indices.
3241 ** (If the destination is not initially empty, the rowid fields
3242 ** of index entries might need to change.)
3243 **
3244 ** (2) The destination has a unique index. (The xfer optimization
3245 ** is unable to test uniqueness.)
3246 **
3247 ** (3) onError is something other than OE_Abort and OE_Rollback.
3248 */
3252 }
3254 u8 insFlags;
3265 }
3272 }
3279 }
3280 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
3285 #endif
3286 {
3288 }
3292 }
3301 }
3306 }
3317 /* This INSERT command is part of a VACUUM operation, which guarantees
3318 ** that the destination table is empty. If all indexed columns use
3319 ** collation sequence BINARY, then it can also be assumed that the
3320 ** index will be populated by inserting keys in strictly sorted
3321 ** order. In this case, instead of seeking within the b-tree as part
3322 ** of every OP_IdxInsert opcode, an OP_SeekEnd is added before the
3323 ** OP_IdxInsert to seek to the point within the b-tree where each key
3324 ** should be inserted. This is faster.
3325 **
3326 ** If any of the indexed columns use a collation sequence other than
3327 ** BINARY, this optimization is disabled. This is because the user
3328 ** might change the definition of a collation sequence and then run
3329 ** a VACUUM command. In that case keys may not be written in strictly
3330 ** sorted order. */
3334 }
3339 }
3342 }
3348 ){
3350 }
3351 }
3358 }
3370 }
3371 }