xref: /sqlite-3.40.0/src/insert.c (revision 9a243e69)
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 */
15 #include "sqliteInt.h"
16 
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 */
26 void sqlite3OpenTable(
27   Parse *pParse,  /* Generate code into this VDBE */
28   int iCur,       /* The cursor number of the table */
29   int iDb,        /* The database index in sqlite3.aDb[] */
30   Table *pTab,    /* The table to be opened */
31   int opcode      /* OP_OpenRead or OP_OpenWrite */
32 ){
33   Vdbe *v;
34   assert( !IsVirtual(pTab) );
35   v = sqlite3GetVdbe(pParse);
36   assert( opcode==OP_OpenWrite || opcode==OP_OpenRead );
37   sqlite3TableLock(pParse, iDb, pTab->tnum,
38                    (opcode==OP_OpenWrite)?1:0, pTab->zName);
39   if( HasRowid(pTab) ){
40     sqlite3VdbeAddOp4Int(v, opcode, iCur, pTab->tnum, iDb, pTab->nCol);
41     VdbeComment((v, "%s", pTab->zName));
42   }else{
43     Index *pPk = sqlite3PrimaryKeyIndex(pTab);
44     assert( pPk!=0 );
45     assert( pPk->tnum==pTab->tnum );
46     sqlite3VdbeAddOp3(v, opcode, iCur, pPk->tnum, iDb);
47     sqlite3VdbeSetP4KeyInfo(pParse, pPk);
48     VdbeComment((v, "%s", pTab->zName));
49   }
50 }
51 
52 /*
53 ** Return a pointer to the column affinity string associated with index
54 ** pIdx. A column affinity string has one character for each column in
55 ** the table, according to the affinity of the column:
56 **
57 **  Character      Column affinity
58 **  ------------------------------
59 **  'A'            BLOB
60 **  'B'            TEXT
61 **  'C'            NUMERIC
62 **  'D'            INTEGER
63 **  'F'            REAL
64 **
65 ** An extra 'D' is appended to the end of the string to cover the
66 ** rowid that appears as the last column in every index.
67 **
68 ** Memory for the buffer containing the column index affinity string
69 ** is managed along with the rest of the Index structure. It will be
70 ** released when sqlite3DeleteIndex() is called.
71 */
72 const char *sqlite3IndexAffinityStr(sqlite3 *db, Index *pIdx){
73   if( !pIdx->zColAff ){
74     /* The first time a column affinity string for a particular index is
75     ** required, it is allocated and populated here. It is then stored as
76     ** a member of the Index structure for subsequent use.
77     **
78     ** The column affinity string will eventually be deleted by
79     ** sqliteDeleteIndex() when the Index structure itself is cleaned
80     ** up.
81     */
82     int n;
83     Table *pTab = pIdx->pTable;
84     pIdx->zColAff = (char *)sqlite3DbMallocRaw(0, pIdx->nColumn+1);
85     if( !pIdx->zColAff ){
86       sqlite3OomFault(db);
87       return 0;
88     }
89     for(n=0; n<pIdx->nColumn; n++){
90       i16 x = pIdx->aiColumn[n];
91       if( x>=0 ){
92         pIdx->zColAff[n] = pTab->aCol[x].affinity;
93       }else if( x==XN_ROWID ){
94         pIdx->zColAff[n] = SQLITE_AFF_INTEGER;
95       }else{
96         char aff;
97         assert( x==XN_EXPR );
98         assert( pIdx->aColExpr!=0 );
99         aff = sqlite3ExprAffinity(pIdx->aColExpr->a[n].pExpr);
100         if( aff==0 ) aff = SQLITE_AFF_BLOB;
101         pIdx->zColAff[n] = aff;
102       }
103     }
104     pIdx->zColAff[n] = 0;
105   }
106 
107   return pIdx->zColAff;
108 }
109 
110 /*
111 ** Compute the affinity string for table pTab, if it has not already been
112 ** computed.  As an optimization, omit trailing SQLITE_AFF_BLOB affinities.
113 **
114 ** If the affinity exists (if it is no entirely SQLITE_AFF_BLOB values) and
115 ** if iReg>0 then code an OP_Affinity opcode that will set the affinities
116 ** for register iReg and following.  Or if affinities exists and iReg==0,
117 ** then just set the P4 operand of the previous opcode (which should  be
118 ** an OP_MakeRecord) to the affinity string.
119 **
120 ** A column affinity string has one character per column:
121 **
122 **  Character      Column affinity
123 **  ------------------------------
124 **  'A'            BLOB
125 **  'B'            TEXT
126 **  'C'            NUMERIC
127 **  'D'            INTEGER
128 **  'E'            REAL
129 */
130 void sqlite3TableAffinity(Vdbe *v, Table *pTab, int iReg){
131   int i;
132   char *zColAff = pTab->zColAff;
133   if( zColAff==0 ){
134     sqlite3 *db = sqlite3VdbeDb(v);
135     zColAff = (char *)sqlite3DbMallocRaw(0, pTab->nCol+1);
136     if( !zColAff ){
137       sqlite3OomFault(db);
138       return;
139     }
140 
141     for(i=0; i<pTab->nCol; i++){
142       zColAff[i] = pTab->aCol[i].affinity;
143     }
144     do{
145       zColAff[i--] = 0;
146     }while( i>=0 && zColAff[i]==SQLITE_AFF_BLOB );
147     pTab->zColAff = zColAff;
148   }
149   i = sqlite3Strlen30(zColAff);
150   if( i ){
151     if( iReg ){
152       sqlite3VdbeAddOp4(v, OP_Affinity, iReg, i, 0, zColAff, i);
153     }else{
154       sqlite3VdbeChangeP4(v, -1, zColAff, i);
155     }
156   }
157 }
158 
159 /*
160 ** Return non-zero if the table pTab in database iDb or any of its indices
161 ** have been opened at any point in the VDBE program. This is used to see if
162 ** a statement of the form  "INSERT INTO <iDb, pTab> SELECT ..." can
163 ** run without using a temporary table for the results of the SELECT.
164 */
165 static int readsTable(Parse *p, int iDb, Table *pTab){
166   Vdbe *v = sqlite3GetVdbe(p);
167   int i;
168   int iEnd = sqlite3VdbeCurrentAddr(v);
169 #ifndef SQLITE_OMIT_VIRTUALTABLE
170   VTable *pVTab = IsVirtual(pTab) ? sqlite3GetVTable(p->db, pTab) : 0;
171 #endif
172 
173   for(i=1; i<iEnd; i++){
174     VdbeOp *pOp = sqlite3VdbeGetOp(v, i);
175     assert( pOp!=0 );
176     if( pOp->opcode==OP_OpenRead && pOp->p3==iDb ){
177       Index *pIndex;
178       int tnum = pOp->p2;
179       if( tnum==pTab->tnum ){
180         return 1;
181       }
182       for(pIndex=pTab->pIndex; pIndex; pIndex=pIndex->pNext){
183         if( tnum==pIndex->tnum ){
184           return 1;
185         }
186       }
187     }
188 #ifndef SQLITE_OMIT_VIRTUALTABLE
189     if( pOp->opcode==OP_VOpen && pOp->p4.pVtab==pVTab ){
190       assert( pOp->p4.pVtab!=0 );
191       assert( pOp->p4type==P4_VTAB );
192       return 1;
193     }
194 #endif
195   }
196   return 0;
197 }
198 
199 #ifndef SQLITE_OMIT_AUTOINCREMENT
200 /*
201 ** Locate or create an AutoincInfo structure associated with table pTab
202 ** which is in database iDb.  Return the register number for the register
203 ** that holds the maximum rowid.  Return zero if pTab is not an AUTOINCREMENT
204 ** table.  (Also return zero when doing a VACUUM since we do not want to
205 ** update the AUTOINCREMENT counters during a VACUUM.)
206 **
207 ** There is at most one AutoincInfo structure per table even if the
208 ** same table is autoincremented multiple times due to inserts within
209 ** triggers.  A new AutoincInfo structure is created if this is the
210 ** first use of table pTab.  On 2nd and subsequent uses, the original
211 ** AutoincInfo structure is used.
212 **
213 ** Three memory locations are allocated:
214 **
215 **   (1)  Register to hold the name of the pTab table.
216 **   (2)  Register to hold the maximum ROWID of pTab.
217 **   (3)  Register to hold the rowid in sqlite_sequence of pTab
218 **
219 ** The 2nd register is the one that is returned.  That is all the
220 ** insert routine needs to know about.
221 */
222 static int autoIncBegin(
223   Parse *pParse,      /* Parsing context */
224   int iDb,            /* Index of the database holding pTab */
225   Table *pTab         /* The table we are writing to */
226 ){
227   int memId = 0;      /* Register holding maximum rowid */
228   if( (pTab->tabFlags & TF_Autoincrement)!=0
229    && (pParse->db->mDbFlags & DBFLAG_Vacuum)==0
230   ){
231     Parse *pToplevel = sqlite3ParseToplevel(pParse);
232     AutoincInfo *pInfo;
233 
234     pInfo = pToplevel->pAinc;
235     while( pInfo && pInfo->pTab!=pTab ){ pInfo = pInfo->pNext; }
236     if( pInfo==0 ){
237       pInfo = sqlite3DbMallocRawNN(pParse->db, sizeof(*pInfo));
238       if( pInfo==0 ) return 0;
239       pInfo->pNext = pToplevel->pAinc;
240       pToplevel->pAinc = pInfo;
241       pInfo->pTab = pTab;
242       pInfo->iDb = iDb;
243       pToplevel->nMem++;                  /* Register to hold name of table */
244       pInfo->regCtr = ++pToplevel->nMem;  /* Max rowid register */
245       pToplevel->nMem++;                  /* Rowid in sqlite_sequence */
246     }
247     memId = pInfo->regCtr;
248   }
249   return memId;
250 }
251 
252 /*
253 ** This routine generates code that will initialize all of the
254 ** register used by the autoincrement tracker.
255 */
256 void sqlite3AutoincrementBegin(Parse *pParse){
257   AutoincInfo *p;            /* Information about an AUTOINCREMENT */
258   sqlite3 *db = pParse->db;  /* The database connection */
259   Db *pDb;                   /* Database only autoinc table */
260   int memId;                 /* Register holding max rowid */
261   Vdbe *v = pParse->pVdbe;   /* VDBE under construction */
262 
263   /* This routine is never called during trigger-generation.  It is
264   ** only called from the top-level */
265   assert( pParse->pTriggerTab==0 );
266   assert( sqlite3IsToplevel(pParse) );
267 
268   assert( v );   /* We failed long ago if this is not so */
269   for(p = pParse->pAinc; p; p = p->pNext){
270     static const int iLn = VDBE_OFFSET_LINENO(2);
271     static const VdbeOpList autoInc[] = {
272       /* 0  */ {OP_Null,    0,  0, 0},
273       /* 1  */ {OP_Rewind,  0,  9, 0},
274       /* 2  */ {OP_Column,  0,  0, 0},
275       /* 3  */ {OP_Ne,      0,  7, 0},
276       /* 4  */ {OP_Rowid,   0,  0, 0},
277       /* 5  */ {OP_Column,  0,  1, 0},
278       /* 6  */ {OP_Goto,    0,  9, 0},
279       /* 7  */ {OP_Next,    0,  2, 0},
280       /* 8  */ {OP_Integer, 0,  0, 0},
281       /* 9  */ {OP_Close,   0,  0, 0}
282     };
283     VdbeOp *aOp;
284     pDb = &db->aDb[p->iDb];
285     memId = p->regCtr;
286     assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
287     sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenRead);
288     sqlite3VdbeLoadString(v, memId-1, p->pTab->zName);
289     aOp = sqlite3VdbeAddOpList(v, ArraySize(autoInc), autoInc, iLn);
290     if( aOp==0 ) break;
291     aOp[0].p2 = memId;
292     aOp[0].p3 = memId+1;
293     aOp[2].p3 = memId;
294     aOp[3].p1 = memId-1;
295     aOp[3].p3 = memId;
296     aOp[3].p5 = SQLITE_JUMPIFNULL;
297     aOp[4].p2 = memId+1;
298     aOp[5].p3 = memId;
299     aOp[8].p2 = memId;
300   }
301 }
302 
303 /*
304 ** Update the maximum rowid for an autoincrement calculation.
305 **
306 ** This routine should be called when the regRowid register holds a
307 ** new rowid that is about to be inserted.  If that new rowid is
308 ** larger than the maximum rowid in the memId memory cell, then the
309 ** memory cell is updated.
310 */
311 static void autoIncStep(Parse *pParse, int memId, int regRowid){
312   if( memId>0 ){
313     sqlite3VdbeAddOp2(pParse->pVdbe, OP_MemMax, memId, regRowid);
314   }
315 }
316 
317 /*
318 ** This routine generates the code needed to write autoincrement
319 ** maximum rowid values back into the sqlite_sequence register.
320 ** Every statement that might do an INSERT into an autoincrement
321 ** table (either directly or through triggers) needs to call this
322 ** routine just before the "exit" code.
323 */
324 static SQLITE_NOINLINE void autoIncrementEnd(Parse *pParse){
325   AutoincInfo *p;
326   Vdbe *v = pParse->pVdbe;
327   sqlite3 *db = pParse->db;
328 
329   assert( v );
330   for(p = pParse->pAinc; p; p = p->pNext){
331     static const int iLn = VDBE_OFFSET_LINENO(2);
332     static const VdbeOpList autoIncEnd[] = {
333       /* 0 */ {OP_NotNull,     0, 2, 0},
334       /* 1 */ {OP_NewRowid,    0, 0, 0},
335       /* 2 */ {OP_MakeRecord,  0, 2, 0},
336       /* 3 */ {OP_Insert,      0, 0, 0},
337       /* 4 */ {OP_Close,       0, 0, 0}
338     };
339     VdbeOp *aOp;
340     Db *pDb = &db->aDb[p->iDb];
341     int iRec;
342     int memId = p->regCtr;
343 
344     iRec = sqlite3GetTempReg(pParse);
345     assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
346     sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenWrite);
347     aOp = sqlite3VdbeAddOpList(v, ArraySize(autoIncEnd), autoIncEnd, iLn);
348     if( aOp==0 ) break;
349     aOp[0].p1 = memId+1;
350     aOp[1].p2 = memId+1;
351     aOp[2].p1 = memId-1;
352     aOp[2].p3 = iRec;
353     aOp[3].p2 = iRec;
354     aOp[3].p3 = memId+1;
355     aOp[3].p5 = OPFLAG_APPEND;
356     sqlite3ReleaseTempReg(pParse, iRec);
357   }
358 }
359 void sqlite3AutoincrementEnd(Parse *pParse){
360   if( pParse->pAinc ) autoIncrementEnd(pParse);
361 }
362 #else
363 /*
364 ** If SQLITE_OMIT_AUTOINCREMENT is defined, then the three routines
365 ** above are all no-ops
366 */
367 # define autoIncBegin(A,B,C) (0)
368 # define autoIncStep(A,B,C)
369 #endif /* SQLITE_OMIT_AUTOINCREMENT */
370 
371 
372 /* Forward declaration */
373 static int xferOptimization(
374   Parse *pParse,        /* Parser context */
375   Table *pDest,         /* The table we are inserting into */
376   Select *pSelect,      /* A SELECT statement to use as the data source */
377   int onError,          /* How to handle constraint errors */
378   int iDbDest           /* The database of pDest */
379 );
380 
381 /*
382 ** This routine is called to handle SQL of the following forms:
383 **
384 **    insert into TABLE (IDLIST) values(EXPRLIST),(EXPRLIST),...
385 **    insert into TABLE (IDLIST) select
386 **    insert into TABLE (IDLIST) default values
387 **
388 ** The IDLIST following the table name is always optional.  If omitted,
389 ** then a list of all (non-hidden) columns for the table is substituted.
390 ** The IDLIST appears in the pColumn parameter.  pColumn is NULL if IDLIST
391 ** is omitted.
392 **
393 ** For the pSelect parameter holds the values to be inserted for the
394 ** first two forms shown above.  A VALUES clause is really just short-hand
395 ** for a SELECT statement that omits the FROM clause and everything else
396 ** that follows.  If the pSelect parameter is NULL, that means that the
397 ** DEFAULT VALUES form of the INSERT statement is intended.
398 **
399 ** The code generated follows one of four templates.  For a simple
400 ** insert with data coming from a single-row VALUES clause, the code executes
401 ** once straight down through.  Pseudo-code follows (we call this
402 ** the "1st template"):
403 **
404 **         open write cursor to <table> and its indices
405 **         put VALUES clause expressions into registers
406 **         write the resulting record into <table>
407 **         cleanup
408 **
409 ** The three remaining templates assume the statement is of the form
410 **
411 **   INSERT INTO <table> SELECT ...
412 **
413 ** If the SELECT clause is of the restricted form "SELECT * FROM <table2>" -
414 ** in other words if the SELECT pulls all columns from a single table
415 ** and there is no WHERE or LIMIT or GROUP BY or ORDER BY clauses, and
416 ** if <table2> and <table1> are distinct tables but have identical
417 ** schemas, including all the same indices, then a special optimization
418 ** is invoked that copies raw records from <table2> over to <table1>.
419 ** See the xferOptimization() function for the implementation of this
420 ** template.  This is the 2nd template.
421 **
422 **         open a write cursor to <table>
423 **         open read cursor on <table2>
424 **         transfer all records in <table2> over to <table>
425 **         close cursors
426 **         foreach index on <table>
427 **           open a write cursor on the <table> index
428 **           open a read cursor on the corresponding <table2> index
429 **           transfer all records from the read to the write cursors
430 **           close cursors
431 **         end foreach
432 **
433 ** The 3rd template is for when the second template does not apply
434 ** and the SELECT clause does not read from <table> at any time.
435 ** The generated code follows this template:
436 **
437 **         X <- A
438 **         goto B
439 **      A: setup for the SELECT
440 **         loop over the rows in the SELECT
441 **           load values into registers R..R+n
442 **           yield X
443 **         end loop
444 **         cleanup after the SELECT
445 **         end-coroutine X
446 **      B: open write cursor to <table> and its indices
447 **      C: yield X, at EOF goto D
448 **         insert the select result into <table> from R..R+n
449 **         goto C
450 **      D: cleanup
451 **
452 ** The 4th template is used if the insert statement takes its
453 ** values from a SELECT but the data is being inserted into a table
454 ** that is also read as part of the SELECT.  In the third form,
455 ** we have to use an intermediate table to store the results of
456 ** the select.  The template is like this:
457 **
458 **         X <- A
459 **         goto B
460 **      A: setup for the SELECT
461 **         loop over the tables in the SELECT
462 **           load value into register R..R+n
463 **           yield X
464 **         end loop
465 **         cleanup after the SELECT
466 **         end co-routine R
467 **      B: open temp table
468 **      L: yield X, at EOF goto M
469 **         insert row from R..R+n into temp table
470 **         goto L
471 **      M: open write cursor to <table> and its indices
472 **         rewind temp table
473 **      C: loop over rows of intermediate table
474 **           transfer values form intermediate table into <table>
475 **         end loop
476 **      D: cleanup
477 */
478 void sqlite3Insert(
479   Parse *pParse,        /* Parser context */
480   SrcList *pTabList,    /* Name of table into which we are inserting */
481   Select *pSelect,      /* A SELECT statement to use as the data source */
482   IdList *pColumn,      /* Column names corresponding to IDLIST. */
483   int onError           /* How to handle constraint errors */
484 ){
485   sqlite3 *db;          /* The main database structure */
486   Table *pTab;          /* The table to insert into.  aka TABLE */
487   char *zTab;           /* Name of the table into which we are inserting */
488   int i, j;             /* Loop counters */
489   Vdbe *v;              /* Generate code into this virtual machine */
490   Index *pIdx;          /* For looping over indices of the table */
491   int nColumn;          /* Number of columns in the data */
492   int nHidden = 0;      /* Number of hidden columns if TABLE is virtual */
493   int iDataCur = 0;     /* VDBE cursor that is the main data repository */
494   int iIdxCur = 0;      /* First index cursor */
495   int ipkColumn = -1;   /* Column that is the INTEGER PRIMARY KEY */
496   int endOfLoop;        /* Label for the end of the insertion loop */
497   int srcTab = 0;       /* Data comes from this temporary cursor if >=0 */
498   int addrInsTop = 0;   /* Jump to label "D" */
499   int addrCont = 0;     /* Top of insert loop. Label "C" in templates 3 and 4 */
500   SelectDest dest;      /* Destination for SELECT on rhs of INSERT */
501   int iDb;              /* Index of database holding TABLE */
502   u8 useTempTable = 0;  /* Store SELECT results in intermediate table */
503   u8 appendFlag = 0;    /* True if the insert is likely to be an append */
504   u8 withoutRowid;      /* 0 for normal table.  1 for WITHOUT ROWID table */
505   u8 bIdListInOrder;    /* True if IDLIST is in table order */
506   ExprList *pList = 0;  /* List of VALUES() to be inserted  */
507 
508   /* Register allocations */
509   int regFromSelect = 0;/* Base register for data coming from SELECT */
510   int regAutoinc = 0;   /* Register holding the AUTOINCREMENT counter */
511   int regRowCount = 0;  /* Memory cell used for the row counter */
512   int regIns;           /* Block of regs holding rowid+data being inserted */
513   int regRowid;         /* registers holding insert rowid */
514   int regData;          /* register holding first column to insert */
515   int *aRegIdx = 0;     /* One register allocated to each index */
516 
517 #ifndef SQLITE_OMIT_TRIGGER
518   int isView;                 /* True if attempting to insert into a view */
519   Trigger *pTrigger;          /* List of triggers on pTab, if required */
520   int tmask;                  /* Mask of trigger times */
521 #endif
522 
523   db = pParse->db;
524   if( pParse->nErr || db->mallocFailed ){
525     goto insert_cleanup;
526   }
527   dest.iSDParm = 0;  /* Suppress a harmless compiler warning */
528 
529   /* If the Select object is really just a simple VALUES() list with a
530   ** single row (the common case) then keep that one row of values
531   ** and discard the other (unused) parts of the pSelect object
532   */
533   if( pSelect && (pSelect->selFlags & SF_Values)!=0 && pSelect->pPrior==0 ){
534     pList = pSelect->pEList;
535     pSelect->pEList = 0;
536     sqlite3SelectDelete(db, pSelect);
537     pSelect = 0;
538   }
539 
540   /* Locate the table into which we will be inserting new information.
541   */
542   assert( pTabList->nSrc==1 );
543   zTab = pTabList->a[0].zName;
544   if( NEVER(zTab==0) ) goto insert_cleanup;
545   pTab = sqlite3SrcListLookup(pParse, pTabList);
546   if( pTab==0 ){
547     goto insert_cleanup;
548   }
549   iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
550   assert( iDb<db->nDb );
551   if( sqlite3AuthCheck(pParse, SQLITE_INSERT, pTab->zName, 0,
552                        db->aDb[iDb].zDbSName) ){
553     goto insert_cleanup;
554   }
555   withoutRowid = !HasRowid(pTab);
556 
557   /* Figure out if we have any triggers and if the table being
558   ** inserted into is a view
559   */
560 #ifndef SQLITE_OMIT_TRIGGER
561   pTrigger = sqlite3TriggersExist(pParse, pTab, TK_INSERT, 0, &tmask);
562   isView = pTab->pSelect!=0;
563 #else
564 # define pTrigger 0
565 # define tmask 0
566 # define isView 0
567 #endif
568 #ifdef SQLITE_OMIT_VIEW
569 # undef isView
570 # define isView 0
571 #endif
572   assert( (pTrigger && tmask) || (pTrigger==0 && tmask==0) );
573 
574   /* If pTab is really a view, make sure it has been initialized.
575   ** ViewGetColumnNames() is a no-op if pTab is not a view.
576   */
577   if( sqlite3ViewGetColumnNames(pParse, pTab) ){
578     goto insert_cleanup;
579   }
580 
581   /* Cannot insert into a read-only table.
582   */
583   if( sqlite3IsReadOnly(pParse, pTab, tmask) ){
584     goto insert_cleanup;
585   }
586 
587   /* Allocate a VDBE
588   */
589   v = sqlite3GetVdbe(pParse);
590   if( v==0 ) goto insert_cleanup;
591   if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
592   sqlite3BeginWriteOperation(pParse, pSelect || pTrigger, iDb);
593 
594 #ifndef SQLITE_OMIT_XFER_OPT
595   /* If the statement is of the form
596   **
597   **       INSERT INTO <table1> SELECT * FROM <table2>;
598   **
599   ** Then special optimizations can be applied that make the transfer
600   ** very fast and which reduce fragmentation of indices.
601   **
602   ** This is the 2nd template.
603   */
604   if( pColumn==0 && xferOptimization(pParse, pTab, pSelect, onError, iDb) ){
605     assert( !pTrigger );
606     assert( pList==0 );
607     goto insert_end;
608   }
609 #endif /* SQLITE_OMIT_XFER_OPT */
610 
611   /* If this is an AUTOINCREMENT table, look up the sequence number in the
612   ** sqlite_sequence table and store it in memory cell regAutoinc.
613   */
614   regAutoinc = autoIncBegin(pParse, iDb, pTab);
615 
616   /* Allocate registers for holding the rowid of the new row,
617   ** the content of the new row, and the assembled row record.
618   */
619   regRowid = regIns = pParse->nMem+1;
620   pParse->nMem += pTab->nCol + 1;
621   if( IsVirtual(pTab) ){
622     regRowid++;
623     pParse->nMem++;
624   }
625   regData = regRowid+1;
626 
627   /* If the INSERT statement included an IDLIST term, then make sure
628   ** all elements of the IDLIST really are columns of the table and
629   ** remember the column indices.
630   **
631   ** If the table has an INTEGER PRIMARY KEY column and that column
632   ** is named in the IDLIST, then record in the ipkColumn variable
633   ** the index into IDLIST of the primary key column.  ipkColumn is
634   ** the index of the primary key as it appears in IDLIST, not as
635   ** is appears in the original table.  (The index of the INTEGER
636   ** PRIMARY KEY in the original table is pTab->iPKey.)
637   */
638   bIdListInOrder = (pTab->tabFlags & TF_OOOHidden)==0;
639   if( pColumn ){
640     for(i=0; i<pColumn->nId; i++){
641       pColumn->a[i].idx = -1;
642     }
643     for(i=0; i<pColumn->nId; i++){
644       for(j=0; j<pTab->nCol; j++){
645         if( sqlite3StrICmp(pColumn->a[i].zName, pTab->aCol[j].zName)==0 ){
646           pColumn->a[i].idx = j;
647           if( i!=j ) bIdListInOrder = 0;
648           if( j==pTab->iPKey ){
649             ipkColumn = i;  assert( !withoutRowid );
650           }
651           break;
652         }
653       }
654       if( j>=pTab->nCol ){
655         if( sqlite3IsRowid(pColumn->a[i].zName) && !withoutRowid ){
656           ipkColumn = i;
657           bIdListInOrder = 0;
658         }else{
659           sqlite3ErrorMsg(pParse, "table %S has no column named %s",
660               pTabList, 0, pColumn->a[i].zName);
661           pParse->checkSchema = 1;
662           goto insert_cleanup;
663         }
664       }
665     }
666   }
667 
668   /* Figure out how many columns of data are supplied.  If the data
669   ** is coming from a SELECT statement, then generate a co-routine that
670   ** produces a single row of the SELECT on each invocation.  The
671   ** co-routine is the common header to the 3rd and 4th templates.
672   */
673   if( pSelect ){
674     /* Data is coming from a SELECT or from a multi-row VALUES clause.
675     ** Generate a co-routine to run the SELECT. */
676     int regYield;       /* Register holding co-routine entry-point */
677     int addrTop;        /* Top of the co-routine */
678     int rc;             /* Result code */
679 
680     regYield = ++pParse->nMem;
681     addrTop = sqlite3VdbeCurrentAddr(v) + 1;
682     sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, addrTop);
683     sqlite3SelectDestInit(&dest, SRT_Coroutine, regYield);
684     dest.iSdst = bIdListInOrder ? regData : 0;
685     dest.nSdst = pTab->nCol;
686     rc = sqlite3Select(pParse, pSelect, &dest);
687     regFromSelect = dest.iSdst;
688     if( rc || db->mallocFailed || pParse->nErr ) goto insert_cleanup;
689     sqlite3VdbeEndCoroutine(v, regYield);
690     sqlite3VdbeJumpHere(v, addrTop - 1);                       /* label B: */
691     assert( pSelect->pEList );
692     nColumn = pSelect->pEList->nExpr;
693 
694     /* Set useTempTable to TRUE if the result of the SELECT statement
695     ** should be written into a temporary table (template 4).  Set to
696     ** FALSE if each output row of the SELECT can be written directly into
697     ** the destination table (template 3).
698     **
699     ** A temp table must be used if the table being updated is also one
700     ** of the tables being read by the SELECT statement.  Also use a
701     ** temp table in the case of row triggers.
702     */
703     if( pTrigger || readsTable(pParse, iDb, pTab) ){
704       useTempTable = 1;
705     }
706 
707     if( useTempTable ){
708       /* Invoke the coroutine to extract information from the SELECT
709       ** and add it to a transient table srcTab.  The code generated
710       ** here is from the 4th template:
711       **
712       **      B: open temp table
713       **      L: yield X, goto M at EOF
714       **         insert row from R..R+n into temp table
715       **         goto L
716       **      M: ...
717       */
718       int regRec;          /* Register to hold packed record */
719       int regTempRowid;    /* Register to hold temp table ROWID */
720       int addrL;           /* Label "L" */
721 
722       srcTab = pParse->nTab++;
723       regRec = sqlite3GetTempReg(pParse);
724       regTempRowid = sqlite3GetTempReg(pParse);
725       sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
726       addrL = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm); VdbeCoverage(v);
727       sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
728       sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regTempRowid);
729       sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regTempRowid);
730       sqlite3VdbeGoto(v, addrL);
731       sqlite3VdbeJumpHere(v, addrL);
732       sqlite3ReleaseTempReg(pParse, regRec);
733       sqlite3ReleaseTempReg(pParse, regTempRowid);
734     }
735   }else{
736     /* This is the case if the data for the INSERT is coming from a
737     ** single-row VALUES clause
738     */
739     NameContext sNC;
740     memset(&sNC, 0, sizeof(sNC));
741     sNC.pParse = pParse;
742     srcTab = -1;
743     assert( useTempTable==0 );
744     if( pList ){
745       nColumn = pList->nExpr;
746       if( sqlite3ResolveExprListNames(&sNC, pList) ){
747         goto insert_cleanup;
748       }
749     }else{
750       nColumn = 0;
751     }
752   }
753 
754   /* If there is no IDLIST term but the table has an integer primary
755   ** key, the set the ipkColumn variable to the integer primary key
756   ** column index in the original table definition.
757   */
758   if( pColumn==0 && nColumn>0 ){
759     ipkColumn = pTab->iPKey;
760   }
761 
762   /* Make sure the number of columns in the source data matches the number
763   ** of columns to be inserted into the table.
764   */
765   for(i=0; i<pTab->nCol; i++){
766     nHidden += (IsHiddenColumn(&pTab->aCol[i]) ? 1 : 0);
767   }
768   if( pColumn==0 && nColumn && nColumn!=(pTab->nCol-nHidden) ){
769     sqlite3ErrorMsg(pParse,
770        "table %S has %d columns but %d values were supplied",
771        pTabList, 0, pTab->nCol-nHidden, nColumn);
772     goto insert_cleanup;
773   }
774   if( pColumn!=0 && nColumn!=pColumn->nId ){
775     sqlite3ErrorMsg(pParse, "%d values for %d columns", nColumn, pColumn->nId);
776     goto insert_cleanup;
777   }
778 
779   /* Initialize the count of rows to be inserted
780   */
781   if( db->flags & SQLITE_CountRows ){
782     regRowCount = ++pParse->nMem;
783     sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
784   }
785 
786   /* If this is not a view, open the table and and all indices */
787   if( !isView ){
788     int nIdx;
789     nIdx = sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, 0, -1, 0,
790                                       &iDataCur, &iIdxCur);
791     aRegIdx = sqlite3DbMallocRawNN(db, sizeof(int)*(nIdx+1));
792     if( aRegIdx==0 ){
793       goto insert_cleanup;
794     }
795     for(i=0, pIdx=pTab->pIndex; i<nIdx; pIdx=pIdx->pNext, i++){
796       assert( pIdx );
797       aRegIdx[i] = ++pParse->nMem;
798       pParse->nMem += pIdx->nColumn;
799     }
800   }
801 
802   /* This is the top of the main insertion loop */
803   if( useTempTable ){
804     /* This block codes the top of loop only.  The complete loop is the
805     ** following pseudocode (template 4):
806     **
807     **         rewind temp table, if empty goto D
808     **      C: loop over rows of intermediate table
809     **           transfer values form intermediate table into <table>
810     **         end loop
811     **      D: ...
812     */
813     addrInsTop = sqlite3VdbeAddOp1(v, OP_Rewind, srcTab); VdbeCoverage(v);
814     addrCont = sqlite3VdbeCurrentAddr(v);
815   }else if( pSelect ){
816     /* This block codes the top of loop only.  The complete loop is the
817     ** following pseudocode (template 3):
818     **
819     **      C: yield X, at EOF goto D
820     **         insert the select result into <table> from R..R+n
821     **         goto C
822     **      D: ...
823     */
824     addrInsTop = addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
825     VdbeCoverage(v);
826   }
827 
828   /* Run the BEFORE and INSTEAD OF triggers, if there are any
829   */
830   endOfLoop = sqlite3VdbeMakeLabel(v);
831   if( tmask & TRIGGER_BEFORE ){
832     int regCols = sqlite3GetTempRange(pParse, pTab->nCol+1);
833 
834     /* build the NEW.* reference row.  Note that if there is an INTEGER
835     ** PRIMARY KEY into which a NULL is being inserted, that NULL will be
836     ** translated into a unique ID for the row.  But on a BEFORE trigger,
837     ** we do not know what the unique ID will be (because the insert has
838     ** not happened yet) so we substitute a rowid of -1
839     */
840     if( ipkColumn<0 ){
841       sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
842     }else{
843       int addr1;
844       assert( !withoutRowid );
845       if( useTempTable ){
846         sqlite3VdbeAddOp3(v, OP_Column, srcTab, ipkColumn, regCols);
847       }else{
848         assert( pSelect==0 );  /* Otherwise useTempTable is true */
849         sqlite3ExprCode(pParse, pList->a[ipkColumn].pExpr, regCols);
850       }
851       addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regCols); VdbeCoverage(v);
852       sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
853       sqlite3VdbeJumpHere(v, addr1);
854       sqlite3VdbeAddOp1(v, OP_MustBeInt, regCols); VdbeCoverage(v);
855     }
856 
857     /* Cannot have triggers on a virtual table. If it were possible,
858     ** this block would have to account for hidden column.
859     */
860     assert( !IsVirtual(pTab) );
861 
862     /* Create the new column data
863     */
864     for(i=j=0; i<pTab->nCol; i++){
865       if( pColumn ){
866         for(j=0; j<pColumn->nId; j++){
867           if( pColumn->a[j].idx==i ) break;
868         }
869       }
870       if( (!useTempTable && !pList) || (pColumn && j>=pColumn->nId)
871             || (pColumn==0 && IsOrdinaryHiddenColumn(&pTab->aCol[i])) ){
872         sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regCols+i+1);
873       }else if( useTempTable ){
874         sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, regCols+i+1);
875       }else{
876         assert( pSelect==0 ); /* Otherwise useTempTable is true */
877         sqlite3ExprCodeAndCache(pParse, pList->a[j].pExpr, regCols+i+1);
878       }
879       if( pColumn==0 && !IsOrdinaryHiddenColumn(&pTab->aCol[i]) ) j++;
880     }
881 
882     /* If this is an INSERT on a view with an INSTEAD OF INSERT trigger,
883     ** do not attempt any conversions before assembling the record.
884     ** If this is a real table, attempt conversions as required by the
885     ** table column affinities.
886     */
887     if( !isView ){
888       sqlite3TableAffinity(v, pTab, regCols+1);
889     }
890 
891     /* Fire BEFORE or INSTEAD OF triggers */
892     sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_BEFORE,
893         pTab, regCols-pTab->nCol-1, onError, endOfLoop);
894 
895     sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol+1);
896   }
897 
898   /* Compute the content of the next row to insert into a range of
899   ** registers beginning at regIns.
900   */
901   if( !isView ){
902     if( IsVirtual(pTab) ){
903       /* The row that the VUpdate opcode will delete: none */
904       sqlite3VdbeAddOp2(v, OP_Null, 0, regIns);
905     }
906     if( ipkColumn>=0 ){
907       if( useTempTable ){
908         sqlite3VdbeAddOp3(v, OP_Column, srcTab, ipkColumn, regRowid);
909       }else if( pSelect ){
910         sqlite3VdbeAddOp2(v, OP_Copy, regFromSelect+ipkColumn, regRowid);
911       }else{
912         VdbeOp *pOp;
913         sqlite3ExprCode(pParse, pList->a[ipkColumn].pExpr, regRowid);
914         pOp = sqlite3VdbeGetOp(v, -1);
915         if( ALWAYS(pOp) && pOp->opcode==OP_Null && !IsVirtual(pTab) ){
916           appendFlag = 1;
917           pOp->opcode = OP_NewRowid;
918           pOp->p1 = iDataCur;
919           pOp->p2 = regRowid;
920           pOp->p3 = regAutoinc;
921         }
922       }
923       /* If the PRIMARY KEY expression is NULL, then use OP_NewRowid
924       ** to generate a unique primary key value.
925       */
926       if( !appendFlag ){
927         int addr1;
928         if( !IsVirtual(pTab) ){
929           addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regRowid); VdbeCoverage(v);
930           sqlite3VdbeAddOp3(v, OP_NewRowid, iDataCur, regRowid, regAutoinc);
931           sqlite3VdbeJumpHere(v, addr1);
932         }else{
933           addr1 = sqlite3VdbeCurrentAddr(v);
934           sqlite3VdbeAddOp2(v, OP_IsNull, regRowid, addr1+2); VdbeCoverage(v);
935         }
936         sqlite3VdbeAddOp1(v, OP_MustBeInt, regRowid); VdbeCoverage(v);
937       }
938     }else if( IsVirtual(pTab) || withoutRowid ){
939       sqlite3VdbeAddOp2(v, OP_Null, 0, regRowid);
940     }else{
941       sqlite3VdbeAddOp3(v, OP_NewRowid, iDataCur, regRowid, regAutoinc);
942       appendFlag = 1;
943     }
944     autoIncStep(pParse, regAutoinc, regRowid);
945 
946     /* Compute data for all columns of the new entry, beginning
947     ** with the first column.
948     */
949     nHidden = 0;
950     for(i=0; i<pTab->nCol; i++){
951       int iRegStore = regRowid+1+i;
952       if( i==pTab->iPKey ){
953         /* The value of the INTEGER PRIMARY KEY column is always a NULL.
954         ** Whenever this column is read, the rowid will be substituted
955         ** in its place.  Hence, fill this column with a NULL to avoid
956         ** taking up data space with information that will never be used.
957         ** As there may be shallow copies of this value, make it a soft-NULL */
958         sqlite3VdbeAddOp1(v, OP_SoftNull, iRegStore);
959         continue;
960       }
961       if( pColumn==0 ){
962         if( IsHiddenColumn(&pTab->aCol[i]) ){
963           j = -1;
964           nHidden++;
965         }else{
966           j = i - nHidden;
967         }
968       }else{
969         for(j=0; j<pColumn->nId; j++){
970           if( pColumn->a[j].idx==i ) break;
971         }
972       }
973       if( j<0 || nColumn==0 || (pColumn && j>=pColumn->nId) ){
974         sqlite3ExprCodeFactorable(pParse, pTab->aCol[i].pDflt, iRegStore);
975       }else if( useTempTable ){
976         sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, iRegStore);
977       }else if( pSelect ){
978         if( regFromSelect!=regData ){
979           sqlite3VdbeAddOp2(v, OP_SCopy, regFromSelect+j, iRegStore);
980         }
981       }else{
982         sqlite3ExprCode(pParse, pList->a[j].pExpr, iRegStore);
983       }
984     }
985 
986     /* Generate code to check constraints and generate index keys and
987     ** do the insertion.
988     */
989 #ifndef SQLITE_OMIT_VIRTUALTABLE
990     if( IsVirtual(pTab) ){
991       const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
992       sqlite3VtabMakeWritable(pParse, pTab);
993       sqlite3VdbeAddOp4(v, OP_VUpdate, 1, pTab->nCol+2, regIns, pVTab, P4_VTAB);
994       sqlite3VdbeChangeP5(v, onError==OE_Default ? OE_Abort : onError);
995       sqlite3MayAbort(pParse);
996     }else
997 #endif
998     {
999       int isReplace;    /* Set to true if constraints may cause a replace */
1000       int bUseSeek;     /* True to use OPFLAG_SEEKRESULT */
1001       sqlite3GenerateConstraintChecks(pParse, pTab, aRegIdx, iDataCur, iIdxCur,
1002           regIns, 0, ipkColumn>=0, onError, endOfLoop, &isReplace, 0
1003       );
1004       sqlite3FkCheck(pParse, pTab, 0, regIns, 0, 0);
1005 
1006       /* Set the OPFLAG_USESEEKRESULT flag if either (a) there are no REPLACE
1007       ** constraints or (b) there are no triggers and this table is not a
1008       ** parent table in a foreign key constraint. It is safe to set the
1009       ** flag in the second case as if any REPLACE constraint is hit, an
1010       ** OP_Delete or OP_IdxDelete instruction will be executed on each
1011       ** cursor that is disturbed. And these instructions both clear the
1012       ** VdbeCursor.seekResult variable, disabling the OPFLAG_USESEEKRESULT
1013       ** functionality.  */
1014       bUseSeek = (isReplace==0 || (pTrigger==0 &&
1015           ((db->flags & SQLITE_ForeignKeys)==0 || sqlite3FkReferences(pTab)==0)
1016       ));
1017       sqlite3CompleteInsertion(pParse, pTab, iDataCur, iIdxCur,
1018           regIns, aRegIdx, 0, appendFlag, bUseSeek
1019       );
1020     }
1021   }
1022 
1023   /* Update the count of rows that are inserted
1024   */
1025   if( (db->flags & SQLITE_CountRows)!=0 ){
1026     sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
1027   }
1028 
1029   if( pTrigger ){
1030     /* Code AFTER triggers */
1031     sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_AFTER,
1032         pTab, regData-2-pTab->nCol, onError, endOfLoop);
1033   }
1034 
1035   /* The bottom of the main insertion loop, if the data source
1036   ** is a SELECT statement.
1037   */
1038   sqlite3VdbeResolveLabel(v, endOfLoop);
1039   if( useTempTable ){
1040     sqlite3VdbeAddOp2(v, OP_Next, srcTab, addrCont); VdbeCoverage(v);
1041     sqlite3VdbeJumpHere(v, addrInsTop);
1042     sqlite3VdbeAddOp1(v, OP_Close, srcTab);
1043   }else if( pSelect ){
1044     sqlite3VdbeGoto(v, addrCont);
1045     sqlite3VdbeJumpHere(v, addrInsTop);
1046   }
1047 
1048 insert_end:
1049   /* Update the sqlite_sequence table by storing the content of the
1050   ** maximum rowid counter values recorded while inserting into
1051   ** autoincrement tables.
1052   */
1053   if( pParse->nested==0 && pParse->pTriggerTab==0 ){
1054     sqlite3AutoincrementEnd(pParse);
1055   }
1056 
1057   /*
1058   ** Return the number of rows inserted. If this routine is
1059   ** generating code because of a call to sqlite3NestedParse(), do not
1060   ** invoke the callback function.
1061   */
1062   if( (db->flags&SQLITE_CountRows) && !pParse->nested && !pParse->pTriggerTab ){
1063     sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
1064     sqlite3VdbeSetNumCols(v, 1);
1065     sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows inserted", SQLITE_STATIC);
1066   }
1067 
1068 insert_cleanup:
1069   sqlite3SrcListDelete(db, pTabList);
1070   sqlite3ExprListDelete(db, pList);
1071   sqlite3SelectDelete(db, pSelect);
1072   sqlite3IdListDelete(db, pColumn);
1073   sqlite3DbFree(db, aRegIdx);
1074 }
1075 
1076 /* Make sure "isView" and other macros defined above are undefined. Otherwise
1077 ** they may interfere with compilation of other functions in this file
1078 ** (or in another file, if this file becomes part of the amalgamation).  */
1079 #ifdef isView
1080  #undef isView
1081 #endif
1082 #ifdef pTrigger
1083  #undef pTrigger
1084 #endif
1085 #ifdef tmask
1086  #undef tmask
1087 #endif
1088 
1089 /*
1090 ** Meanings of bits in of pWalker->eCode for checkConstraintUnchanged()
1091 */
1092 #define CKCNSTRNT_COLUMN   0x01    /* CHECK constraint uses a changing column */
1093 #define CKCNSTRNT_ROWID    0x02    /* CHECK constraint references the ROWID */
1094 
1095 /* This is the Walker callback from checkConstraintUnchanged().  Set
1096 ** bit 0x01 of pWalker->eCode if
1097 ** pWalker->eCode to 0 if this expression node references any of the
1098 ** columns that are being modifed by an UPDATE statement.
1099 */
1100 static int checkConstraintExprNode(Walker *pWalker, Expr *pExpr){
1101   if( pExpr->op==TK_COLUMN ){
1102     assert( pExpr->iColumn>=0 || pExpr->iColumn==-1 );
1103     if( pExpr->iColumn>=0 ){
1104       if( pWalker->u.aiCol[pExpr->iColumn]>=0 ){
1105         pWalker->eCode |= CKCNSTRNT_COLUMN;
1106       }
1107     }else{
1108       pWalker->eCode |= CKCNSTRNT_ROWID;
1109     }
1110   }
1111   return WRC_Continue;
1112 }
1113 
1114 /*
1115 ** pExpr is a CHECK constraint on a row that is being UPDATE-ed.  The
1116 ** only columns that are modified by the UPDATE are those for which
1117 ** aiChng[i]>=0, and also the ROWID is modified if chngRowid is true.
1118 **
1119 ** Return true if CHECK constraint pExpr does not use any of the
1120 ** changing columns (or the rowid if it is changing).  In other words,
1121 ** return true if this CHECK constraint can be skipped when validating
1122 ** the new row in the UPDATE statement.
1123 */
1124 static int checkConstraintUnchanged(Expr *pExpr, int *aiChng, int chngRowid){
1125   Walker w;
1126   memset(&w, 0, sizeof(w));
1127   w.eCode = 0;
1128   w.xExprCallback = checkConstraintExprNode;
1129   w.u.aiCol = aiChng;
1130   sqlite3WalkExpr(&w, pExpr);
1131   if( !chngRowid ){
1132     testcase( (w.eCode & CKCNSTRNT_ROWID)!=0 );
1133     w.eCode &= ~CKCNSTRNT_ROWID;
1134   }
1135   testcase( w.eCode==0 );
1136   testcase( w.eCode==CKCNSTRNT_COLUMN );
1137   testcase( w.eCode==CKCNSTRNT_ROWID );
1138   testcase( w.eCode==(CKCNSTRNT_ROWID|CKCNSTRNT_COLUMN) );
1139   return !w.eCode;
1140 }
1141 
1142 /*
1143 ** Generate code to do constraint checks prior to an INSERT or an UPDATE
1144 ** on table pTab.
1145 **
1146 ** The regNewData parameter is the first register in a range that contains
1147 ** the data to be inserted or the data after the update.  There will be
1148 ** pTab->nCol+1 registers in this range.  The first register (the one
1149 ** that regNewData points to) will contain the new rowid, or NULL in the
1150 ** case of a WITHOUT ROWID table.  The second register in the range will
1151 ** contain the content of the first table column.  The third register will
1152 ** contain the content of the second table column.  And so forth.
1153 **
1154 ** The regOldData parameter is similar to regNewData except that it contains
1155 ** the data prior to an UPDATE rather than afterwards.  regOldData is zero
1156 ** for an INSERT.  This routine can distinguish between UPDATE and INSERT by
1157 ** checking regOldData for zero.
1158 **
1159 ** For an UPDATE, the pkChng boolean is true if the true primary key (the
1160 ** rowid for a normal table or the PRIMARY KEY for a WITHOUT ROWID table)
1161 ** might be modified by the UPDATE.  If pkChng is false, then the key of
1162 ** the iDataCur content table is guaranteed to be unchanged by the UPDATE.
1163 **
1164 ** For an INSERT, the pkChng boolean indicates whether or not the rowid
1165 ** was explicitly specified as part of the INSERT statement.  If pkChng
1166 ** is zero, it means that the either rowid is computed automatically or
1167 ** that the table is a WITHOUT ROWID table and has no rowid.  On an INSERT,
1168 ** pkChng will only be true if the INSERT statement provides an integer
1169 ** value for either the rowid column or its INTEGER PRIMARY KEY alias.
1170 **
1171 ** The code generated by this routine will store new index entries into
1172 ** registers identified by aRegIdx[].  No index entry is created for
1173 ** indices where aRegIdx[i]==0.  The order of indices in aRegIdx[] is
1174 ** the same as the order of indices on the linked list of indices
1175 ** at pTab->pIndex.
1176 **
1177 ** The caller must have already opened writeable cursors on the main
1178 ** table and all applicable indices (that is to say, all indices for which
1179 ** aRegIdx[] is not zero).  iDataCur is the cursor for the main table when
1180 ** inserting or updating a rowid table, or the cursor for the PRIMARY KEY
1181 ** index when operating on a WITHOUT ROWID table.  iIdxCur is the cursor
1182 ** for the first index in the pTab->pIndex list.  Cursors for other indices
1183 ** are at iIdxCur+N for the N-th element of the pTab->pIndex list.
1184 **
1185 ** This routine also generates code to check constraints.  NOT NULL,
1186 ** CHECK, and UNIQUE constraints are all checked.  If a constraint fails,
1187 ** then the appropriate action is performed.  There are five possible
1188 ** actions: ROLLBACK, ABORT, FAIL, REPLACE, and IGNORE.
1189 **
1190 **  Constraint type  Action       What Happens
1191 **  ---------------  ----------   ----------------------------------------
1192 **  any              ROLLBACK     The current transaction is rolled back and
1193 **                                sqlite3_step() returns immediately with a
1194 **                                return code of SQLITE_CONSTRAINT.
1195 **
1196 **  any              ABORT        Back out changes from the current command
1197 **                                only (do not do a complete rollback) then
1198 **                                cause sqlite3_step() to return immediately
1199 **                                with SQLITE_CONSTRAINT.
1200 **
1201 **  any              FAIL         Sqlite3_step() returns immediately with a
1202 **                                return code of SQLITE_CONSTRAINT.  The
1203 **                                transaction is not rolled back and any
1204 **                                changes to prior rows are retained.
1205 **
1206 **  any              IGNORE       The attempt in insert or update the current
1207 **                                row is skipped, without throwing an error.
1208 **                                Processing continues with the next row.
1209 **                                (There is an immediate jump to ignoreDest.)
1210 **
1211 **  NOT NULL         REPLACE      The NULL value is replace by the default
1212 **                                value for that column.  If the default value
1213 **                                is NULL, the action is the same as ABORT.
1214 **
1215 **  UNIQUE           REPLACE      The other row that conflicts with the row
1216 **                                being inserted is removed.
1217 **
1218 **  CHECK            REPLACE      Illegal.  The results in an exception.
1219 **
1220 ** Which action to take is determined by the overrideError parameter.
1221 ** Or if overrideError==OE_Default, then the pParse->onError parameter
1222 ** is used.  Or if pParse->onError==OE_Default then the onError value
1223 ** for the constraint is used.
1224 */
1225 void sqlite3GenerateConstraintChecks(
1226   Parse *pParse,       /* The parser context */
1227   Table *pTab,         /* The table being inserted or updated */
1228   int *aRegIdx,        /* Use register aRegIdx[i] for index i.  0 for unused */
1229   int iDataCur,        /* Canonical data cursor (main table or PK index) */
1230   int iIdxCur,         /* First index cursor */
1231   int regNewData,      /* First register in a range holding values to insert */
1232   int regOldData,      /* Previous content.  0 for INSERTs */
1233   u8 pkChng,           /* Non-zero if the rowid or PRIMARY KEY changed */
1234   u8 overrideError,    /* Override onError to this if not OE_Default */
1235   int ignoreDest,      /* Jump to this label on an OE_Ignore resolution */
1236   int *pbMayReplace,   /* OUT: Set to true if constraint may cause a replace */
1237   int *aiChng          /* column i is unchanged if aiChng[i]<0 */
1238 ){
1239   Vdbe *v;             /* VDBE under constrution */
1240   Index *pIdx;         /* Pointer to one of the indices */
1241   Index *pPk = 0;      /* The PRIMARY KEY index */
1242   sqlite3 *db;         /* Database connection */
1243   int i;               /* loop counter */
1244   int ix;              /* Index loop counter */
1245   int nCol;            /* Number of columns */
1246   int onError;         /* Conflict resolution strategy */
1247   int addr1;           /* Address of jump instruction */
1248   int seenReplace = 0; /* True if REPLACE is used to resolve INT PK conflict */
1249   int nPkField;        /* Number of fields in PRIMARY KEY. 1 for ROWID tables */
1250   int ipkTop = 0;      /* Top of the rowid change constraint check */
1251   int ipkBottom = 0;   /* Bottom of the rowid change constraint check */
1252   u8 isUpdate;         /* True if this is an UPDATE operation */
1253   u8 bAffinityDone = 0;  /* True if the OP_Affinity operation has been run */
1254 
1255   isUpdate = regOldData!=0;
1256   db = pParse->db;
1257   v = sqlite3GetVdbe(pParse);
1258   assert( v!=0 );
1259   assert( pTab->pSelect==0 );  /* This table is not a VIEW */
1260   nCol = pTab->nCol;
1261 
1262   /* pPk is the PRIMARY KEY index for WITHOUT ROWID tables and NULL for
1263   ** normal rowid tables.  nPkField is the number of key fields in the
1264   ** pPk index or 1 for a rowid table.  In other words, nPkField is the
1265   ** number of fields in the true primary key of the table. */
1266   if( HasRowid(pTab) ){
1267     pPk = 0;
1268     nPkField = 1;
1269   }else{
1270     pPk = sqlite3PrimaryKeyIndex(pTab);
1271     nPkField = pPk->nKeyCol;
1272   }
1273 
1274   /* Record that this module has started */
1275   VdbeModuleComment((v, "BEGIN: GenCnstCks(%d,%d,%d,%d,%d)",
1276                      iDataCur, iIdxCur, regNewData, regOldData, pkChng));
1277 
1278   /* Test all NOT NULL constraints.
1279   */
1280   for(i=0; i<nCol; i++){
1281     if( i==pTab->iPKey ){
1282       continue;        /* ROWID is never NULL */
1283     }
1284     if( aiChng && aiChng[i]<0 ){
1285       /* Don't bother checking for NOT NULL on columns that do not change */
1286       continue;
1287     }
1288     onError = pTab->aCol[i].notNull;
1289     if( onError==OE_None ) continue;  /* This column is allowed to be NULL */
1290     if( overrideError!=OE_Default ){
1291       onError = overrideError;
1292     }else if( onError==OE_Default ){
1293       onError = OE_Abort;
1294     }
1295     if( onError==OE_Replace && pTab->aCol[i].pDflt==0 ){
1296       onError = OE_Abort;
1297     }
1298     assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
1299         || onError==OE_Ignore || onError==OE_Replace );
1300     switch( onError ){
1301       case OE_Abort:
1302         sqlite3MayAbort(pParse);
1303         /* Fall through */
1304       case OE_Rollback:
1305       case OE_Fail: {
1306         char *zMsg = sqlite3MPrintf(db, "%s.%s", pTab->zName,
1307                                     pTab->aCol[i].zName);
1308         sqlite3VdbeAddOp3(v, OP_HaltIfNull, SQLITE_CONSTRAINT_NOTNULL, onError,
1309                           regNewData+1+i);
1310         sqlite3VdbeAppendP4(v, zMsg, P4_DYNAMIC);
1311         sqlite3VdbeChangeP5(v, P5_ConstraintNotNull);
1312         VdbeCoverage(v);
1313         break;
1314       }
1315       case OE_Ignore: {
1316         sqlite3VdbeAddOp2(v, OP_IsNull, regNewData+1+i, ignoreDest);
1317         VdbeCoverage(v);
1318         break;
1319       }
1320       default: {
1321         assert( onError==OE_Replace );
1322         addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regNewData+1+i);
1323            VdbeCoverage(v);
1324         sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regNewData+1+i);
1325         sqlite3VdbeJumpHere(v, addr1);
1326         break;
1327       }
1328     }
1329   }
1330 
1331   /* Test all CHECK constraints
1332   */
1333 #ifndef SQLITE_OMIT_CHECK
1334   if( pTab->pCheck && (db->flags & SQLITE_IgnoreChecks)==0 ){
1335     ExprList *pCheck = pTab->pCheck;
1336     pParse->iSelfTab = -(regNewData+1);
1337     onError = overrideError!=OE_Default ? overrideError : OE_Abort;
1338     for(i=0; i<pCheck->nExpr; i++){
1339       int allOk;
1340       Expr *pExpr = pCheck->a[i].pExpr;
1341       if( aiChng && checkConstraintUnchanged(pExpr, aiChng, pkChng) ) continue;
1342       allOk = sqlite3VdbeMakeLabel(v);
1343       sqlite3ExprIfTrue(pParse, pExpr, allOk, SQLITE_JUMPIFNULL);
1344       if( onError==OE_Ignore ){
1345         sqlite3VdbeGoto(v, ignoreDest);
1346       }else{
1347         char *zName = pCheck->a[i].zName;
1348         if( zName==0 ) zName = pTab->zName;
1349         if( onError==OE_Replace ) onError = OE_Abort; /* IMP: R-15569-63625 */
1350         sqlite3HaltConstraint(pParse, SQLITE_CONSTRAINT_CHECK,
1351                               onError, zName, P4_TRANSIENT,
1352                               P5_ConstraintCheck);
1353       }
1354       sqlite3VdbeResolveLabel(v, allOk);
1355     }
1356     pParse->iSelfTab = 0;
1357   }
1358 #endif /* !defined(SQLITE_OMIT_CHECK) */
1359 
1360   /* If rowid is changing, make sure the new rowid does not previously
1361   ** exist in the table.
1362   */
1363   if( pkChng && pPk==0 ){
1364     int addrRowidOk = sqlite3VdbeMakeLabel(v);
1365 
1366     /* Figure out what action to take in case of a rowid collision */
1367     onError = pTab->keyConf;
1368     if( overrideError!=OE_Default ){
1369       onError = overrideError;
1370     }else if( onError==OE_Default ){
1371       onError = OE_Abort;
1372     }
1373 
1374     if( isUpdate ){
1375       /* pkChng!=0 does not mean that the rowid has changed, only that
1376       ** it might have changed.  Skip the conflict logic below if the rowid
1377       ** is unchanged. */
1378       sqlite3VdbeAddOp3(v, OP_Eq, regNewData, addrRowidOk, regOldData);
1379       sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
1380       VdbeCoverage(v);
1381     }
1382 
1383     /* If the response to a rowid conflict is REPLACE but the response
1384     ** to some other UNIQUE constraint is FAIL or IGNORE, then we need
1385     ** to defer the running of the rowid conflict checking until after
1386     ** the UNIQUE constraints have run.
1387     */
1388     if( onError==OE_Replace && overrideError!=OE_Replace ){
1389       for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
1390         if( pIdx->onError==OE_Ignore || pIdx->onError==OE_Fail ){
1391           ipkTop = sqlite3VdbeAddOp0(v, OP_Goto);
1392           break;
1393         }
1394       }
1395     }
1396 
1397     /* Check to see if the new rowid already exists in the table.  Skip
1398     ** the following conflict logic if it does not. */
1399     sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, addrRowidOk, regNewData);
1400     VdbeCoverage(v);
1401 
1402     /* Generate code that deals with a rowid collision */
1403     switch( onError ){
1404       default: {
1405         onError = OE_Abort;
1406         /* Fall thru into the next case */
1407       }
1408       case OE_Rollback:
1409       case OE_Abort:
1410       case OE_Fail: {
1411         sqlite3RowidConstraint(pParse, onError, pTab);
1412         break;
1413       }
1414       case OE_Replace: {
1415         /* If there are DELETE triggers on this table and the
1416         ** recursive-triggers flag is set, call GenerateRowDelete() to
1417         ** remove the conflicting row from the table. This will fire
1418         ** the triggers and remove both the table and index b-tree entries.
1419         **
1420         ** Otherwise, if there are no triggers or the recursive-triggers
1421         ** flag is not set, but the table has one or more indexes, call
1422         ** GenerateRowIndexDelete(). This removes the index b-tree entries
1423         ** only. The table b-tree entry will be replaced by the new entry
1424         ** when it is inserted.
1425         **
1426         ** If either GenerateRowDelete() or GenerateRowIndexDelete() is called,
1427         ** also invoke MultiWrite() to indicate that this VDBE may require
1428         ** statement rollback (if the statement is aborted after the delete
1429         ** takes place). Earlier versions called sqlite3MultiWrite() regardless,
1430         ** but being more selective here allows statements like:
1431         **
1432         **   REPLACE INTO t(rowid) VALUES($newrowid)
1433         **
1434         ** to run without a statement journal if there are no indexes on the
1435         ** table.
1436         */
1437         Trigger *pTrigger = 0;
1438         if( db->flags&SQLITE_RecTriggers ){
1439           pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
1440         }
1441         if( pTrigger || sqlite3FkRequired(pParse, pTab, 0, 0) ){
1442           sqlite3MultiWrite(pParse);
1443           sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
1444                                    regNewData, 1, 0, OE_Replace, 1, -1);
1445         }else{
1446 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
1447           if( HasRowid(pTab) ){
1448             /* This OP_Delete opcode fires the pre-update-hook only. It does
1449             ** not modify the b-tree. It is more efficient to let the coming
1450             ** OP_Insert replace the existing entry than it is to delete the
1451             ** existing entry and then insert a new one. */
1452             sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, OPFLAG_ISNOOP);
1453             sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
1454           }
1455 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
1456           if( pTab->pIndex ){
1457             sqlite3MultiWrite(pParse);
1458             sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur,0,-1);
1459           }
1460         }
1461         seenReplace = 1;
1462         break;
1463       }
1464       case OE_Ignore: {
1465         /*assert( seenReplace==0 );*/
1466         sqlite3VdbeGoto(v, ignoreDest);
1467         break;
1468       }
1469     }
1470     sqlite3VdbeResolveLabel(v, addrRowidOk);
1471     if( ipkTop ){
1472       ipkBottom = sqlite3VdbeAddOp0(v, OP_Goto);
1473       sqlite3VdbeJumpHere(v, ipkTop);
1474     }
1475   }
1476 
1477   /* Test all UNIQUE constraints by creating entries for each UNIQUE
1478   ** index and making sure that duplicate entries do not already exist.
1479   ** Compute the revised record entries for indices as we go.
1480   **
1481   ** This loop also handles the case of the PRIMARY KEY index for a
1482   ** WITHOUT ROWID table.
1483   */
1484   for(ix=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, ix++){
1485     int regIdx;          /* Range of registers hold conent for pIdx */
1486     int regR;            /* Range of registers holding conflicting PK */
1487     int iThisCur;        /* Cursor for this UNIQUE index */
1488     int addrUniqueOk;    /* Jump here if the UNIQUE constraint is satisfied */
1489 
1490     if( aRegIdx[ix]==0 ) continue;  /* Skip indices that do not change */
1491     if( bAffinityDone==0 ){
1492       sqlite3TableAffinity(v, pTab, regNewData+1);
1493       bAffinityDone = 1;
1494     }
1495     iThisCur = iIdxCur+ix;
1496     addrUniqueOk = sqlite3VdbeMakeLabel(v);
1497 
1498     /* Skip partial indices for which the WHERE clause is not true */
1499     if( pIdx->pPartIdxWhere ){
1500       sqlite3VdbeAddOp2(v, OP_Null, 0, aRegIdx[ix]);
1501       pParse->iSelfTab = -(regNewData+1);
1502       sqlite3ExprIfFalseDup(pParse, pIdx->pPartIdxWhere, addrUniqueOk,
1503                             SQLITE_JUMPIFNULL);
1504       pParse->iSelfTab = 0;
1505     }
1506 
1507     /* Create a record for this index entry as it should appear after
1508     ** the insert or update.  Store that record in the aRegIdx[ix] register
1509     */
1510     regIdx = aRegIdx[ix]+1;
1511     for(i=0; i<pIdx->nColumn; i++){
1512       int iField = pIdx->aiColumn[i];
1513       int x;
1514       if( iField==XN_EXPR ){
1515         pParse->iSelfTab = -(regNewData+1);
1516         sqlite3ExprCodeCopy(pParse, pIdx->aColExpr->a[i].pExpr, regIdx+i);
1517         pParse->iSelfTab = 0;
1518         VdbeComment((v, "%s column %d", pIdx->zName, i));
1519       }else{
1520         if( iField==XN_ROWID || iField==pTab->iPKey ){
1521           x = regNewData;
1522         }else{
1523           x = iField + regNewData + 1;
1524         }
1525         sqlite3VdbeAddOp2(v, iField<0 ? OP_IntCopy : OP_SCopy, x, regIdx+i);
1526         VdbeComment((v, "%s", iField<0 ? "rowid" : pTab->aCol[iField].zName));
1527       }
1528     }
1529     sqlite3VdbeAddOp3(v, OP_MakeRecord, regIdx, pIdx->nColumn, aRegIdx[ix]);
1530     VdbeComment((v, "for %s", pIdx->zName));
1531 #ifdef SQLITE_ENABLE_NULL_TRIM
1532     if( pIdx->idxType==2 ) sqlite3SetMakeRecordP5(v, pIdx->pTable);
1533 #endif
1534 
1535     /* In an UPDATE operation, if this index is the PRIMARY KEY index
1536     ** of a WITHOUT ROWID table and there has been no change the
1537     ** primary key, then no collision is possible.  The collision detection
1538     ** logic below can all be skipped. */
1539     if( isUpdate && pPk==pIdx && pkChng==0 ){
1540       sqlite3VdbeResolveLabel(v, addrUniqueOk);
1541       continue;
1542     }
1543 
1544     /* Find out what action to take in case there is a uniqueness conflict */
1545     onError = pIdx->onError;
1546     if( onError==OE_None ){
1547       sqlite3VdbeResolveLabel(v, addrUniqueOk);
1548       continue;  /* pIdx is not a UNIQUE index */
1549     }
1550     if( overrideError!=OE_Default ){
1551       onError = overrideError;
1552     }else if( onError==OE_Default ){
1553       onError = OE_Abort;
1554     }
1555 
1556     /* Collision detection may be omitted if all of the following are true:
1557     **   (1) The conflict resolution algorithm is REPLACE
1558     **   (2) The table is a WITHOUT ROWID table
1559     **   (3) There are no secondary indexes on the table
1560     **   (4) No delete triggers need to be fired if there is a conflict
1561     **   (5) No FK constraint counters need to be updated if a conflict occurs.
1562     */
1563     if( (ix==0 && pIdx->pNext==0)                   /* Condition 3 */
1564      && pPk==pIdx                                   /* Condition 2 */
1565      && onError==OE_Replace                         /* Condition 1 */
1566      && ( 0==(db->flags&SQLITE_RecTriggers) ||      /* Condition 4 */
1567           0==sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0))
1568      && ( 0==(db->flags&SQLITE_ForeignKeys) ||      /* Condition 5 */
1569          (0==pTab->pFKey && 0==sqlite3FkReferences(pTab)))
1570     ){
1571       sqlite3VdbeResolveLabel(v, addrUniqueOk);
1572       continue;
1573     }
1574 
1575     /* Check to see if the new index entry will be unique */
1576     sqlite3VdbeAddOp4Int(v, OP_NoConflict, iThisCur, addrUniqueOk,
1577                          regIdx, pIdx->nKeyCol); VdbeCoverage(v);
1578 
1579     /* Generate code to handle collisions */
1580     regR = (pIdx==pPk) ? regIdx : sqlite3GetTempRange(pParse, nPkField);
1581     if( isUpdate || onError==OE_Replace ){
1582       if( HasRowid(pTab) ){
1583         sqlite3VdbeAddOp2(v, OP_IdxRowid, iThisCur, regR);
1584         /* Conflict only if the rowid of the existing index entry
1585         ** is different from old-rowid */
1586         if( isUpdate ){
1587           sqlite3VdbeAddOp3(v, OP_Eq, regR, addrUniqueOk, regOldData);
1588           sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
1589           VdbeCoverage(v);
1590         }
1591       }else{
1592         int x;
1593         /* Extract the PRIMARY KEY from the end of the index entry and
1594         ** store it in registers regR..regR+nPk-1 */
1595         if( pIdx!=pPk ){
1596           for(i=0; i<pPk->nKeyCol; i++){
1597             assert( pPk->aiColumn[i]>=0 );
1598             x = sqlite3ColumnOfIndex(pIdx, pPk->aiColumn[i]);
1599             sqlite3VdbeAddOp3(v, OP_Column, iThisCur, x, regR+i);
1600             VdbeComment((v, "%s.%s", pTab->zName,
1601                          pTab->aCol[pPk->aiColumn[i]].zName));
1602           }
1603         }
1604         if( isUpdate ){
1605           /* If currently processing the PRIMARY KEY of a WITHOUT ROWID
1606           ** table, only conflict if the new PRIMARY KEY values are actually
1607           ** different from the old.
1608           **
1609           ** For a UNIQUE index, only conflict if the PRIMARY KEY values
1610           ** of the matched index row are different from the original PRIMARY
1611           ** KEY values of this row before the update.  */
1612           int addrJump = sqlite3VdbeCurrentAddr(v)+pPk->nKeyCol;
1613           int op = OP_Ne;
1614           int regCmp = (IsPrimaryKeyIndex(pIdx) ? regIdx : regR);
1615 
1616           for(i=0; i<pPk->nKeyCol; i++){
1617             char *p4 = (char*)sqlite3LocateCollSeq(pParse, pPk->azColl[i]);
1618             x = pPk->aiColumn[i];
1619             assert( x>=0 );
1620             if( i==(pPk->nKeyCol-1) ){
1621               addrJump = addrUniqueOk;
1622               op = OP_Eq;
1623             }
1624             sqlite3VdbeAddOp4(v, op,
1625                 regOldData+1+x, addrJump, regCmp+i, p4, P4_COLLSEQ
1626             );
1627             sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
1628             VdbeCoverageIf(v, op==OP_Eq);
1629             VdbeCoverageIf(v, op==OP_Ne);
1630           }
1631         }
1632       }
1633     }
1634 
1635     /* Generate code that executes if the new index entry is not unique */
1636     assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
1637         || onError==OE_Ignore || onError==OE_Replace );
1638     switch( onError ){
1639       case OE_Rollback:
1640       case OE_Abort:
1641       case OE_Fail: {
1642         sqlite3UniqueConstraint(pParse, onError, pIdx);
1643         break;
1644       }
1645       case OE_Ignore: {
1646         sqlite3VdbeGoto(v, ignoreDest);
1647         break;
1648       }
1649       default: {
1650         Trigger *pTrigger = 0;
1651         assert( onError==OE_Replace );
1652         sqlite3MultiWrite(pParse);
1653         if( db->flags&SQLITE_RecTriggers ){
1654           pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
1655         }
1656         sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
1657             regR, nPkField, 0, OE_Replace,
1658             (pIdx==pPk ? ONEPASS_SINGLE : ONEPASS_OFF), iThisCur);
1659         seenReplace = 1;
1660         break;
1661       }
1662     }
1663     sqlite3VdbeResolveLabel(v, addrUniqueOk);
1664     if( regR!=regIdx ) sqlite3ReleaseTempRange(pParse, regR, nPkField);
1665   }
1666   if( ipkTop ){
1667     sqlite3VdbeGoto(v, ipkTop+1);
1668     sqlite3VdbeJumpHere(v, ipkBottom);
1669   }
1670 
1671   *pbMayReplace = seenReplace;
1672   VdbeModuleComment((v, "END: GenCnstCks(%d)", seenReplace));
1673 }
1674 
1675 #ifdef SQLITE_ENABLE_NULL_TRIM
1676 /*
1677 ** Change the P5 operand on the last opcode (which should be an OP_MakeRecord)
1678 ** to be the number of columns in table pTab that must not be NULL-trimmed.
1679 **
1680 ** Or if no columns of pTab may be NULL-trimmed, leave P5 at zero.
1681 */
1682 void sqlite3SetMakeRecordP5(Vdbe *v, Table *pTab){
1683   u16 i;
1684 
1685   /* Records with omitted columns are only allowed for schema format
1686   ** version 2 and later (SQLite version 3.1.4, 2005-02-20). */
1687   if( pTab->pSchema->file_format<2 ) return;
1688 
1689   for(i=pTab->nCol-1; i>0; i--){
1690     if( pTab->aCol[i].pDflt!=0 ) break;
1691     if( pTab->aCol[i].colFlags & COLFLAG_PRIMKEY ) break;
1692   }
1693   sqlite3VdbeChangeP5(v, i+1);
1694 }
1695 #endif
1696 
1697 /*
1698 ** This routine generates code to finish the INSERT or UPDATE operation
1699 ** that was started by a prior call to sqlite3GenerateConstraintChecks.
1700 ** A consecutive range of registers starting at regNewData contains the
1701 ** rowid and the content to be inserted.
1702 **
1703 ** The arguments to this routine should be the same as the first six
1704 ** arguments to sqlite3GenerateConstraintChecks.
1705 */
1706 void sqlite3CompleteInsertion(
1707   Parse *pParse,      /* The parser context */
1708   Table *pTab,        /* the table into which we are inserting */
1709   int iDataCur,       /* Cursor of the canonical data source */
1710   int iIdxCur,        /* First index cursor */
1711   int regNewData,     /* Range of content */
1712   int *aRegIdx,       /* Register used by each index.  0 for unused indices */
1713   int update_flags,   /* True for UPDATE, False for INSERT */
1714   int appendBias,     /* True if this is likely to be an append */
1715   int useSeekResult   /* True to set the USESEEKRESULT flag on OP_[Idx]Insert */
1716 ){
1717   Vdbe *v;            /* Prepared statements under construction */
1718   Index *pIdx;        /* An index being inserted or updated */
1719   u8 pik_flags;       /* flag values passed to the btree insert */
1720   int regData;        /* Content registers (after the rowid) */
1721   int regRec;         /* Register holding assembled record for the table */
1722   int i;              /* Loop counter */
1723   u8 bAffinityDone = 0; /* True if OP_Affinity has been run already */
1724 
1725   assert( update_flags==0
1726        || update_flags==OPFLAG_ISUPDATE
1727        || update_flags==(OPFLAG_ISUPDATE|OPFLAG_SAVEPOSITION)
1728   );
1729 
1730   v = sqlite3GetVdbe(pParse);
1731   assert( v!=0 );
1732   assert( pTab->pSelect==0 );  /* This table is not a VIEW */
1733   for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
1734     if( aRegIdx[i]==0 ) continue;
1735     bAffinityDone = 1;
1736     if( pIdx->pPartIdxWhere ){
1737       sqlite3VdbeAddOp2(v, OP_IsNull, aRegIdx[i], sqlite3VdbeCurrentAddr(v)+2);
1738       VdbeCoverage(v);
1739     }
1740     pik_flags = (useSeekResult ? OPFLAG_USESEEKRESULT : 0);
1741     if( IsPrimaryKeyIndex(pIdx) && !HasRowid(pTab) ){
1742       assert( pParse->nested==0 );
1743       pik_flags |= OPFLAG_NCHANGE;
1744       pik_flags |= (update_flags & OPFLAG_SAVEPOSITION);
1745 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
1746       if( update_flags==0 ){
1747         sqlite3VdbeAddOp4(v, OP_InsertInt,
1748             iIdxCur+i, aRegIdx[i], 0, (char*)pTab, P4_TABLE
1749         );
1750         sqlite3VdbeChangeP5(v, OPFLAG_ISNOOP);
1751       }
1752 #endif
1753     }
1754     sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iIdxCur+i, aRegIdx[i],
1755                          aRegIdx[i]+1,
1756                          pIdx->uniqNotNull ? pIdx->nKeyCol: pIdx->nColumn);
1757     sqlite3VdbeChangeP5(v, pik_flags);
1758   }
1759   if( !HasRowid(pTab) ) return;
1760   regData = regNewData + 1;
1761   regRec = sqlite3GetTempReg(pParse);
1762   sqlite3VdbeAddOp3(v, OP_MakeRecord, regData, pTab->nCol, regRec);
1763   sqlite3SetMakeRecordP5(v, pTab);
1764   if( !bAffinityDone ){
1765     sqlite3TableAffinity(v, pTab, 0);
1766     sqlite3ExprCacheAffinityChange(pParse, regData, pTab->nCol);
1767   }
1768   if( pParse->nested ){
1769     pik_flags = 0;
1770   }else{
1771     pik_flags = OPFLAG_NCHANGE;
1772     pik_flags |= (update_flags?update_flags:OPFLAG_LASTROWID);
1773   }
1774   if( appendBias ){
1775     pik_flags |= OPFLAG_APPEND;
1776   }
1777   if( useSeekResult ){
1778     pik_flags |= OPFLAG_USESEEKRESULT;
1779   }
1780   sqlite3VdbeAddOp3(v, OP_Insert, iDataCur, regRec, regNewData);
1781   if( !pParse->nested ){
1782     sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
1783   }
1784   sqlite3VdbeChangeP5(v, pik_flags);
1785 }
1786 
1787 /*
1788 ** Allocate cursors for the pTab table and all its indices and generate
1789 ** code to open and initialized those cursors.
1790 **
1791 ** The cursor for the object that contains the complete data (normally
1792 ** the table itself, but the PRIMARY KEY index in the case of a WITHOUT
1793 ** ROWID table) is returned in *piDataCur.  The first index cursor is
1794 ** returned in *piIdxCur.  The number of indices is returned.
1795 **
1796 ** Use iBase as the first cursor (either the *piDataCur for rowid tables
1797 ** or the first index for WITHOUT ROWID tables) if it is non-negative.
1798 ** If iBase is negative, then allocate the next available cursor.
1799 **
1800 ** For a rowid table, *piDataCur will be exactly one less than *piIdxCur.
1801 ** For a WITHOUT ROWID table, *piDataCur will be somewhere in the range
1802 ** of *piIdxCurs, depending on where the PRIMARY KEY index appears on the
1803 ** pTab->pIndex list.
1804 **
1805 ** If pTab is a virtual table, then this routine is a no-op and the
1806 ** *piDataCur and *piIdxCur values are left uninitialized.
1807 */
1808 int sqlite3OpenTableAndIndices(
1809   Parse *pParse,   /* Parsing context */
1810   Table *pTab,     /* Table to be opened */
1811   int op,          /* OP_OpenRead or OP_OpenWrite */
1812   u8 p5,           /* P5 value for OP_Open* opcodes (except on WITHOUT ROWID) */
1813   int iBase,       /* Use this for the table cursor, if there is one */
1814   u8 *aToOpen,     /* If not NULL: boolean for each table and index */
1815   int *piDataCur,  /* Write the database source cursor number here */
1816   int *piIdxCur    /* Write the first index cursor number here */
1817 ){
1818   int i;
1819   int iDb;
1820   int iDataCur;
1821   Index *pIdx;
1822   Vdbe *v;
1823 
1824   assert( op==OP_OpenRead || op==OP_OpenWrite );
1825   assert( op==OP_OpenWrite || p5==0 );
1826   if( IsVirtual(pTab) ){
1827     /* This routine is a no-op for virtual tables. Leave the output
1828     ** variables *piDataCur and *piIdxCur uninitialized so that valgrind
1829     ** can detect if they are used by mistake in the caller. */
1830     return 0;
1831   }
1832   iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
1833   v = sqlite3GetVdbe(pParse);
1834   assert( v!=0 );
1835   if( iBase<0 ) iBase = pParse->nTab;
1836   iDataCur = iBase++;
1837   if( piDataCur ) *piDataCur = iDataCur;
1838   if( HasRowid(pTab) && (aToOpen==0 || aToOpen[0]) ){
1839     sqlite3OpenTable(pParse, iDataCur, iDb, pTab, op);
1840   }else{
1841     sqlite3TableLock(pParse, iDb, pTab->tnum, op==OP_OpenWrite, pTab->zName);
1842   }
1843   if( piIdxCur ) *piIdxCur = iBase;
1844   for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
1845     int iIdxCur = iBase++;
1846     assert( pIdx->pSchema==pTab->pSchema );
1847     if( IsPrimaryKeyIndex(pIdx) && !HasRowid(pTab) ){
1848       if( piDataCur ) *piDataCur = iIdxCur;
1849       p5 = 0;
1850     }
1851     if( aToOpen==0 || aToOpen[i+1] ){
1852       sqlite3VdbeAddOp3(v, op, iIdxCur, pIdx->tnum, iDb);
1853       sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
1854       sqlite3VdbeChangeP5(v, p5);
1855       VdbeComment((v, "%s", pIdx->zName));
1856     }
1857   }
1858   if( iBase>pParse->nTab ) pParse->nTab = iBase;
1859   return i;
1860 }
1861 
1862 
1863 #ifdef SQLITE_TEST
1864 /*
1865 ** The following global variable is incremented whenever the
1866 ** transfer optimization is used.  This is used for testing
1867 ** purposes only - to make sure the transfer optimization really
1868 ** is happening when it is supposed to.
1869 */
1870 int sqlite3_xferopt_count;
1871 #endif /* SQLITE_TEST */
1872 
1873 
1874 #ifndef SQLITE_OMIT_XFER_OPT
1875 /*
1876 ** Check to see if index pSrc is compatible as a source of data
1877 ** for index pDest in an insert transfer optimization.  The rules
1878 ** for a compatible index:
1879 **
1880 **    *   The index is over the same set of columns
1881 **    *   The same DESC and ASC markings occurs on all columns
1882 **    *   The same onError processing (OE_Abort, OE_Ignore, etc)
1883 **    *   The same collating sequence on each column
1884 **    *   The index has the exact same WHERE clause
1885 */
1886 static int xferCompatibleIndex(Index *pDest, Index *pSrc){
1887   int i;
1888   assert( pDest && pSrc );
1889   assert( pDest->pTable!=pSrc->pTable );
1890   if( pDest->nKeyCol!=pSrc->nKeyCol ){
1891     return 0;   /* Different number of columns */
1892   }
1893   if( pDest->onError!=pSrc->onError ){
1894     return 0;   /* Different conflict resolution strategies */
1895   }
1896   for(i=0; i<pSrc->nKeyCol; i++){
1897     if( pSrc->aiColumn[i]!=pDest->aiColumn[i] ){
1898       return 0;   /* Different columns indexed */
1899     }
1900     if( pSrc->aiColumn[i]==XN_EXPR ){
1901       assert( pSrc->aColExpr!=0 && pDest->aColExpr!=0 );
1902       if( sqlite3ExprCompare(0, pSrc->aColExpr->a[i].pExpr,
1903                              pDest->aColExpr->a[i].pExpr, -1)!=0 ){
1904         return 0;   /* Different expressions in the index */
1905       }
1906     }
1907     if( pSrc->aSortOrder[i]!=pDest->aSortOrder[i] ){
1908       return 0;   /* Different sort orders */
1909     }
1910     if( sqlite3_stricmp(pSrc->azColl[i],pDest->azColl[i])!=0 ){
1911       return 0;   /* Different collating sequences */
1912     }
1913   }
1914   if( sqlite3ExprCompare(0, pSrc->pPartIdxWhere, pDest->pPartIdxWhere, -1) ){
1915     return 0;     /* Different WHERE clauses */
1916   }
1917 
1918   /* If no test above fails then the indices must be compatible */
1919   return 1;
1920 }
1921 
1922 /*
1923 ** Attempt the transfer optimization on INSERTs of the form
1924 **
1925 **     INSERT INTO tab1 SELECT * FROM tab2;
1926 **
1927 ** The xfer optimization transfers raw records from tab2 over to tab1.
1928 ** Columns are not decoded and reassembled, which greatly improves
1929 ** performance.  Raw index records are transferred in the same way.
1930 **
1931 ** The xfer optimization is only attempted if tab1 and tab2 are compatible.
1932 ** There are lots of rules for determining compatibility - see comments
1933 ** embedded in the code for details.
1934 **
1935 ** This routine returns TRUE if the optimization is guaranteed to be used.
1936 ** Sometimes the xfer optimization will only work if the destination table
1937 ** is empty - a factor that can only be determined at run-time.  In that
1938 ** case, this routine generates code for the xfer optimization but also
1939 ** does a test to see if the destination table is empty and jumps over the
1940 ** xfer optimization code if the test fails.  In that case, this routine
1941 ** returns FALSE so that the caller will know to go ahead and generate
1942 ** an unoptimized transfer.  This routine also returns FALSE if there
1943 ** is no chance that the xfer optimization can be applied.
1944 **
1945 ** This optimization is particularly useful at making VACUUM run faster.
1946 */
1947 static int xferOptimization(
1948   Parse *pParse,        /* Parser context */
1949   Table *pDest,         /* The table we are inserting into */
1950   Select *pSelect,      /* A SELECT statement to use as the data source */
1951   int onError,          /* How to handle constraint errors */
1952   int iDbDest           /* The database of pDest */
1953 ){
1954   sqlite3 *db = pParse->db;
1955   ExprList *pEList;                /* The result set of the SELECT */
1956   Table *pSrc;                     /* The table in the FROM clause of SELECT */
1957   Index *pSrcIdx, *pDestIdx;       /* Source and destination indices */
1958   struct SrcList_item *pItem;      /* An element of pSelect->pSrc */
1959   int i;                           /* Loop counter */
1960   int iDbSrc;                      /* The database of pSrc */
1961   int iSrc, iDest;                 /* Cursors from source and destination */
1962   int addr1, addr2;                /* Loop addresses */
1963   int emptyDestTest = 0;           /* Address of test for empty pDest */
1964   int emptySrcTest = 0;            /* Address of test for empty pSrc */
1965   Vdbe *v;                         /* The VDBE we are building */
1966   int regAutoinc;                  /* Memory register used by AUTOINC */
1967   int destHasUniqueIdx = 0;        /* True if pDest has a UNIQUE index */
1968   int regData, regRowid;           /* Registers holding data and rowid */
1969 
1970   if( pSelect==0 ){
1971     return 0;   /* Must be of the form  INSERT INTO ... SELECT ... */
1972   }
1973   if( pParse->pWith || pSelect->pWith ){
1974     /* Do not attempt to process this query if there are an WITH clauses
1975     ** attached to it. Proceeding may generate a false "no such table: xxx"
1976     ** error if pSelect reads from a CTE named "xxx".  */
1977     return 0;
1978   }
1979   if( sqlite3TriggerList(pParse, pDest) ){
1980     return 0;   /* tab1 must not have triggers */
1981   }
1982 #ifndef SQLITE_OMIT_VIRTUALTABLE
1983   if( IsVirtual(pDest) ){
1984     return 0;   /* tab1 must not be a virtual table */
1985   }
1986 #endif
1987   if( onError==OE_Default ){
1988     if( pDest->iPKey>=0 ) onError = pDest->keyConf;
1989     if( onError==OE_Default ) onError = OE_Abort;
1990   }
1991   assert(pSelect->pSrc);   /* allocated even if there is no FROM clause */
1992   if( pSelect->pSrc->nSrc!=1 ){
1993     return 0;   /* FROM clause must have exactly one term */
1994   }
1995   if( pSelect->pSrc->a[0].pSelect ){
1996     return 0;   /* FROM clause cannot contain a subquery */
1997   }
1998   if( pSelect->pWhere ){
1999     return 0;   /* SELECT may not have a WHERE clause */
2000   }
2001   if( pSelect->pOrderBy ){
2002     return 0;   /* SELECT may not have an ORDER BY clause */
2003   }
2004   /* Do not need to test for a HAVING clause.  If HAVING is present but
2005   ** there is no ORDER BY, we will get an error. */
2006   if( pSelect->pGroupBy ){
2007     return 0;   /* SELECT may not have a GROUP BY clause */
2008   }
2009   if( pSelect->pLimit ){
2010     return 0;   /* SELECT may not have a LIMIT clause */
2011   }
2012   assert( pSelect->pOffset==0 );  /* Must be so if pLimit==0 */
2013   if( pSelect->pPrior ){
2014     return 0;   /* SELECT may not be a compound query */
2015   }
2016   if( pSelect->selFlags & SF_Distinct ){
2017     return 0;   /* SELECT may not be DISTINCT */
2018   }
2019   pEList = pSelect->pEList;
2020   assert( pEList!=0 );
2021   if( pEList->nExpr!=1 ){
2022     return 0;   /* The result set must have exactly one column */
2023   }
2024   assert( pEList->a[0].pExpr );
2025   if( pEList->a[0].pExpr->op!=TK_ASTERISK ){
2026     return 0;   /* The result set must be the special operator "*" */
2027   }
2028 
2029   /* At this point we have established that the statement is of the
2030   ** correct syntactic form to participate in this optimization.  Now
2031   ** we have to check the semantics.
2032   */
2033   pItem = pSelect->pSrc->a;
2034   pSrc = sqlite3LocateTableItem(pParse, 0, pItem);
2035   if( pSrc==0 ){
2036     return 0;   /* FROM clause does not contain a real table */
2037   }
2038   if( pSrc==pDest ){
2039     return 0;   /* tab1 and tab2 may not be the same table */
2040   }
2041   if( HasRowid(pDest)!=HasRowid(pSrc) ){
2042     return 0;   /* source and destination must both be WITHOUT ROWID or not */
2043   }
2044 #ifndef SQLITE_OMIT_VIRTUALTABLE
2045   if( IsVirtual(pSrc) ){
2046     return 0;   /* tab2 must not be a virtual table */
2047   }
2048 #endif
2049   if( pSrc->pSelect ){
2050     return 0;   /* tab2 may not be a view */
2051   }
2052   if( pDest->nCol!=pSrc->nCol ){
2053     return 0;   /* Number of columns must be the same in tab1 and tab2 */
2054   }
2055   if( pDest->iPKey!=pSrc->iPKey ){
2056     return 0;   /* Both tables must have the same INTEGER PRIMARY KEY */
2057   }
2058   for(i=0; i<pDest->nCol; i++){
2059     Column *pDestCol = &pDest->aCol[i];
2060     Column *pSrcCol = &pSrc->aCol[i];
2061 #ifdef SQLITE_ENABLE_HIDDEN_COLUMNS
2062     if( (db->mDbFlags & DBFLAG_Vacuum)==0
2063      && (pDestCol->colFlags | pSrcCol->colFlags) & COLFLAG_HIDDEN
2064     ){
2065       return 0;    /* Neither table may have __hidden__ columns */
2066     }
2067 #endif
2068     if( pDestCol->affinity!=pSrcCol->affinity ){
2069       return 0;    /* Affinity must be the same on all columns */
2070     }
2071     if( sqlite3_stricmp(pDestCol->zColl, pSrcCol->zColl)!=0 ){
2072       return 0;    /* Collating sequence must be the same on all columns */
2073     }
2074     if( pDestCol->notNull && !pSrcCol->notNull ){
2075       return 0;    /* tab2 must be NOT NULL if tab1 is */
2076     }
2077     /* Default values for second and subsequent columns need to match. */
2078     if( i>0 ){
2079       assert( pDestCol->pDflt==0 || pDestCol->pDflt->op==TK_SPAN );
2080       assert( pSrcCol->pDflt==0 || pSrcCol->pDflt->op==TK_SPAN );
2081       if( (pDestCol->pDflt==0)!=(pSrcCol->pDflt==0)
2082        || (pDestCol->pDflt && strcmp(pDestCol->pDflt->u.zToken,
2083                                        pSrcCol->pDflt->u.zToken)!=0)
2084       ){
2085         return 0;    /* Default values must be the same for all columns */
2086       }
2087     }
2088   }
2089   for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
2090     if( IsUniqueIndex(pDestIdx) ){
2091       destHasUniqueIdx = 1;
2092     }
2093     for(pSrcIdx=pSrc->pIndex; pSrcIdx; pSrcIdx=pSrcIdx->pNext){
2094       if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
2095     }
2096     if( pSrcIdx==0 ){
2097       return 0;    /* pDestIdx has no corresponding index in pSrc */
2098     }
2099   }
2100 #ifndef SQLITE_OMIT_CHECK
2101   if( pDest->pCheck && sqlite3ExprListCompare(pSrc->pCheck,pDest->pCheck,-1) ){
2102     return 0;   /* Tables have different CHECK constraints.  Ticket #2252 */
2103   }
2104 #endif
2105 #ifndef SQLITE_OMIT_FOREIGN_KEY
2106   /* Disallow the transfer optimization if the destination table constains
2107   ** any foreign key constraints.  This is more restrictive than necessary.
2108   ** But the main beneficiary of the transfer optimization is the VACUUM
2109   ** command, and the VACUUM command disables foreign key constraints.  So
2110   ** the extra complication to make this rule less restrictive is probably
2111   ** not worth the effort.  Ticket [6284df89debdfa61db8073e062908af0c9b6118e]
2112   */
2113   if( (db->flags & SQLITE_ForeignKeys)!=0 && pDest->pFKey!=0 ){
2114     return 0;
2115   }
2116 #endif
2117   if( (db->flags & SQLITE_CountRows)!=0 ){
2118     return 0;  /* xfer opt does not play well with PRAGMA count_changes */
2119   }
2120 
2121   /* If we get this far, it means that the xfer optimization is at
2122   ** least a possibility, though it might only work if the destination
2123   ** table (tab1) is initially empty.
2124   */
2125 #ifdef SQLITE_TEST
2126   sqlite3_xferopt_count++;
2127 #endif
2128   iDbSrc = sqlite3SchemaToIndex(db, pSrc->pSchema);
2129   v = sqlite3GetVdbe(pParse);
2130   sqlite3CodeVerifySchema(pParse, iDbSrc);
2131   iSrc = pParse->nTab++;
2132   iDest = pParse->nTab++;
2133   regAutoinc = autoIncBegin(pParse, iDbDest, pDest);
2134   regData = sqlite3GetTempReg(pParse);
2135   regRowid = sqlite3GetTempReg(pParse);
2136   sqlite3OpenTable(pParse, iDest, iDbDest, pDest, OP_OpenWrite);
2137   assert( HasRowid(pDest) || destHasUniqueIdx );
2138   if( (db->mDbFlags & DBFLAG_Vacuum)==0 && (
2139       (pDest->iPKey<0 && pDest->pIndex!=0)          /* (1) */
2140    || destHasUniqueIdx                              /* (2) */
2141    || (onError!=OE_Abort && onError!=OE_Rollback)   /* (3) */
2142   )){
2143     /* In some circumstances, we are able to run the xfer optimization
2144     ** only if the destination table is initially empty. Unless the
2145     ** DBFLAG_Vacuum flag is set, this block generates code to make
2146     ** that determination. If DBFLAG_Vacuum is set, then the destination
2147     ** table is always empty.
2148     **
2149     ** Conditions under which the destination must be empty:
2150     **
2151     ** (1) There is no INTEGER PRIMARY KEY but there are indices.
2152     **     (If the destination is not initially empty, the rowid fields
2153     **     of index entries might need to change.)
2154     **
2155     ** (2) The destination has a unique index.  (The xfer optimization
2156     **     is unable to test uniqueness.)
2157     **
2158     ** (3) onError is something other than OE_Abort and OE_Rollback.
2159     */
2160     addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iDest, 0); VdbeCoverage(v);
2161     emptyDestTest = sqlite3VdbeAddOp0(v, OP_Goto);
2162     sqlite3VdbeJumpHere(v, addr1);
2163   }
2164   if( HasRowid(pSrc) ){
2165     u8 insFlags;
2166     sqlite3OpenTable(pParse, iSrc, iDbSrc, pSrc, OP_OpenRead);
2167     emptySrcTest = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0); VdbeCoverage(v);
2168     if( pDest->iPKey>=0 ){
2169       addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
2170       addr2 = sqlite3VdbeAddOp3(v, OP_NotExists, iDest, 0, regRowid);
2171       VdbeCoverage(v);
2172       sqlite3RowidConstraint(pParse, onError, pDest);
2173       sqlite3VdbeJumpHere(v, addr2);
2174       autoIncStep(pParse, regAutoinc, regRowid);
2175     }else if( pDest->pIndex==0 ){
2176       addr1 = sqlite3VdbeAddOp2(v, OP_NewRowid, iDest, regRowid);
2177     }else{
2178       addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
2179       assert( (pDest->tabFlags & TF_Autoincrement)==0 );
2180     }
2181     sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
2182     if( db->mDbFlags & DBFLAG_Vacuum ){
2183       sqlite3VdbeAddOp1(v, OP_SeekEnd, iDest);
2184       insFlags = OPFLAG_NCHANGE|OPFLAG_LASTROWID|
2185                            OPFLAG_APPEND|OPFLAG_USESEEKRESULT;
2186     }else{
2187       insFlags = OPFLAG_NCHANGE|OPFLAG_LASTROWID|OPFLAG_APPEND;
2188     }
2189     sqlite3VdbeAddOp4(v, OP_Insert, iDest, regData, regRowid,
2190                       (char*)pDest, P4_TABLE);
2191     sqlite3VdbeChangeP5(v, insFlags);
2192     sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1); VdbeCoverage(v);
2193     sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
2194     sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
2195   }else{
2196     sqlite3TableLock(pParse, iDbDest, pDest->tnum, 1, pDest->zName);
2197     sqlite3TableLock(pParse, iDbSrc, pSrc->tnum, 0, pSrc->zName);
2198   }
2199   for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
2200     u8 idxInsFlags = 0;
2201     for(pSrcIdx=pSrc->pIndex; ALWAYS(pSrcIdx); pSrcIdx=pSrcIdx->pNext){
2202       if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
2203     }
2204     assert( pSrcIdx );
2205     sqlite3VdbeAddOp3(v, OP_OpenRead, iSrc, pSrcIdx->tnum, iDbSrc);
2206     sqlite3VdbeSetP4KeyInfo(pParse, pSrcIdx);
2207     VdbeComment((v, "%s", pSrcIdx->zName));
2208     sqlite3VdbeAddOp3(v, OP_OpenWrite, iDest, pDestIdx->tnum, iDbDest);
2209     sqlite3VdbeSetP4KeyInfo(pParse, pDestIdx);
2210     sqlite3VdbeChangeP5(v, OPFLAG_BULKCSR);
2211     VdbeComment((v, "%s", pDestIdx->zName));
2212     addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0); VdbeCoverage(v);
2213     sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
2214     if( db->mDbFlags & DBFLAG_Vacuum ){
2215       /* This INSERT command is part of a VACUUM operation, which guarantees
2216       ** that the destination table is empty. If all indexed columns use
2217       ** collation sequence BINARY, then it can also be assumed that the
2218       ** index will be populated by inserting keys in strictly sorted
2219       ** order. In this case, instead of seeking within the b-tree as part
2220       ** of every OP_IdxInsert opcode, an OP_SeekEnd is added before the
2221       ** OP_IdxInsert to seek to the point within the b-tree where each key
2222       ** should be inserted. This is faster.
2223       **
2224       ** If any of the indexed columns use a collation sequence other than
2225       ** BINARY, this optimization is disabled. This is because the user
2226       ** might change the definition of a collation sequence and then run
2227       ** a VACUUM command. In that case keys may not be written in strictly
2228       ** sorted order.  */
2229       for(i=0; i<pSrcIdx->nColumn; i++){
2230         const char *zColl = pSrcIdx->azColl[i];
2231         if( sqlite3_stricmp(sqlite3StrBINARY, zColl) ) break;
2232       }
2233       if( i==pSrcIdx->nColumn ){
2234         idxInsFlags = OPFLAG_USESEEKRESULT;
2235         sqlite3VdbeAddOp1(v, OP_SeekEnd, iDest);
2236       }
2237     }
2238     if( !HasRowid(pSrc) && pDestIdx->idxType==2 ){
2239       idxInsFlags |= OPFLAG_NCHANGE;
2240     }
2241     sqlite3VdbeAddOp2(v, OP_IdxInsert, iDest, regData);
2242     sqlite3VdbeChangeP5(v, idxInsFlags|OPFLAG_APPEND);
2243     sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1+1); VdbeCoverage(v);
2244     sqlite3VdbeJumpHere(v, addr1);
2245     sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
2246     sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
2247   }
2248   if( emptySrcTest ) sqlite3VdbeJumpHere(v, emptySrcTest);
2249   sqlite3ReleaseTempReg(pParse, regRowid);
2250   sqlite3ReleaseTempReg(pParse, regData);
2251   if( emptyDestTest ){
2252     sqlite3AutoincrementEnd(pParse);
2253     sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_OK, 0);
2254     sqlite3VdbeJumpHere(v, emptyDestTest);
2255     sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
2256     return 0;
2257   }else{
2258     return 1;
2259   }
2260 }
2261 #endif /* SQLITE_OMIT_XFER_OPT */
2262