xref: /sqlite-3.40.0/src/insert.c (revision 8c53b4e7)
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   assert( zColAff!=0 );
150   i = sqlite3Strlen30NN(zColAff);
151   if( i ){
152     if( iReg ){
153       sqlite3VdbeAddOp4(v, OP_Affinity, iReg, i, 0, zColAff, i);
154     }else{
155       sqlite3VdbeChangeP4(v, -1, zColAff, i);
156     }
157   }
158 }
159 
160 /*
161 ** Return non-zero if the table pTab in database iDb or any of its indices
162 ** have been opened at any point in the VDBE program. This is used to see if
163 ** a statement of the form  "INSERT INTO <iDb, pTab> SELECT ..." can
164 ** run without using a temporary table for the results of the SELECT.
165 */
166 static int readsTable(Parse *p, int iDb, Table *pTab){
167   Vdbe *v = sqlite3GetVdbe(p);
168   int i;
169   int iEnd = sqlite3VdbeCurrentAddr(v);
170 #ifndef SQLITE_OMIT_VIRTUALTABLE
171   VTable *pVTab = IsVirtual(pTab) ? sqlite3GetVTable(p->db, pTab) : 0;
172 #endif
173 
174   for(i=1; i<iEnd; i++){
175     VdbeOp *pOp = sqlite3VdbeGetOp(v, i);
176     assert( pOp!=0 );
177     if( pOp->opcode==OP_OpenRead && pOp->p3==iDb ){
178       Index *pIndex;
179       int tnum = pOp->p2;
180       if( tnum==pTab->tnum ){
181         return 1;
182       }
183       for(pIndex=pTab->pIndex; pIndex; pIndex=pIndex->pNext){
184         if( tnum==pIndex->tnum ){
185           return 1;
186         }
187       }
188     }
189 #ifndef SQLITE_OMIT_VIRTUALTABLE
190     if( pOp->opcode==OP_VOpen && pOp->p4.pVtab==pVTab ){
191       assert( pOp->p4.pVtab!=0 );
192       assert( pOp->p4type==P4_VTAB );
193       return 1;
194     }
195 #endif
196   }
197   return 0;
198 }
199 
200 #ifndef SQLITE_OMIT_AUTOINCREMENT
201 /*
202 ** Locate or create an AutoincInfo structure associated with table pTab
203 ** which is in database iDb.  Return the register number for the register
204 ** that holds the maximum rowid.  Return zero if pTab is not an AUTOINCREMENT
205 ** table.  (Also return zero when doing a VACUUM since we do not want to
206 ** update the AUTOINCREMENT counters during a VACUUM.)
207 **
208 ** There is at most one AutoincInfo structure per table even if the
209 ** same table is autoincremented multiple times due to inserts within
210 ** triggers.  A new AutoincInfo structure is created if this is the
211 ** first use of table pTab.  On 2nd and subsequent uses, the original
212 ** AutoincInfo structure is used.
213 **
214 ** Four consecutive registers are allocated:
215 **
216 **   (1)  The name of the pTab table.
217 **   (2)  The maximum ROWID of pTab.
218 **   (3)  The rowid in sqlite_sequence of pTab
219 **   (4)  The original value of the max ROWID in pTab, or NULL if none
220 **
221 ** The 2nd register is the one that is returned.  That is all the
222 ** insert routine needs to know about.
223 */
224 static int autoIncBegin(
225   Parse *pParse,      /* Parsing context */
226   int iDb,            /* Index of the database holding pTab */
227   Table *pTab         /* The table we are writing to */
228 ){
229   int memId = 0;      /* Register holding maximum rowid */
230   assert( pParse->db->aDb[iDb].pSchema!=0 );
231   if( (pTab->tabFlags & TF_Autoincrement)!=0
232    && (pParse->db->mDbFlags & DBFLAG_Vacuum)==0
233   ){
234     Parse *pToplevel = sqlite3ParseToplevel(pParse);
235     AutoincInfo *pInfo;
236     Table *pSeqTab = pParse->db->aDb[iDb].pSchema->pSeqTab;
237 
238     /* Verify that the sqlite_sequence table exists and is an ordinary
239     ** rowid table with exactly two columns.
240     ** Ticket d8dc2b3a58cd5dc2918a1d4acb 2018-05-23 */
241     if( pSeqTab==0
242      || !HasRowid(pSeqTab)
243      || IsVirtual(pSeqTab)
244      || pSeqTab->nCol!=2
245     ){
246       pParse->nErr++;
247       pParse->rc = SQLITE_CORRUPT_SEQUENCE;
248       return 0;
249     }
250 
251     pInfo = pToplevel->pAinc;
252     while( pInfo && pInfo->pTab!=pTab ){ pInfo = pInfo->pNext; }
253     if( pInfo==0 ){
254       pInfo = sqlite3DbMallocRawNN(pParse->db, sizeof(*pInfo));
255       if( pInfo==0 ) return 0;
256       pInfo->pNext = pToplevel->pAinc;
257       pToplevel->pAinc = pInfo;
258       pInfo->pTab = pTab;
259       pInfo->iDb = iDb;
260       pToplevel->nMem++;                  /* Register to hold name of table */
261       pInfo->regCtr = ++pToplevel->nMem;  /* Max rowid register */
262       pToplevel->nMem +=2;       /* Rowid in sqlite_sequence + orig max val */
263     }
264     memId = pInfo->regCtr;
265   }
266   return memId;
267 }
268 
269 /*
270 ** This routine generates code that will initialize all of the
271 ** register used by the autoincrement tracker.
272 */
273 void sqlite3AutoincrementBegin(Parse *pParse){
274   AutoincInfo *p;            /* Information about an AUTOINCREMENT */
275   sqlite3 *db = pParse->db;  /* The database connection */
276   Db *pDb;                   /* Database only autoinc table */
277   int memId;                 /* Register holding max rowid */
278   Vdbe *v = pParse->pVdbe;   /* VDBE under construction */
279 
280   /* This routine is never called during trigger-generation.  It is
281   ** only called from the top-level */
282   assert( pParse->pTriggerTab==0 );
283   assert( sqlite3IsToplevel(pParse) );
284 
285   assert( v );   /* We failed long ago if this is not so */
286   for(p = pParse->pAinc; p; p = p->pNext){
287     static const int iLn = VDBE_OFFSET_LINENO(2);
288     static const VdbeOpList autoInc[] = {
289       /* 0  */ {OP_Null,    0,  0, 0},
290       /* 1  */ {OP_Rewind,  0, 10, 0},
291       /* 2  */ {OP_Column,  0,  0, 0},
292       /* 3  */ {OP_Ne,      0,  9, 0},
293       /* 4  */ {OP_Rowid,   0,  0, 0},
294       /* 5  */ {OP_Column,  0,  1, 0},
295       /* 6  */ {OP_AddImm,  0,  0, 0},
296       /* 7  */ {OP_Copy,    0,  0, 0},
297       /* 8  */ {OP_Goto,    0, 11, 0},
298       /* 9  */ {OP_Next,    0,  2, 0},
299       /* 10 */ {OP_Integer, 0,  0, 0},
300       /* 11 */ {OP_Close,   0,  0, 0}
301     };
302     VdbeOp *aOp;
303     pDb = &db->aDb[p->iDb];
304     memId = p->regCtr;
305     assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
306     sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenRead);
307     sqlite3VdbeLoadString(v, memId-1, p->pTab->zName);
308     aOp = sqlite3VdbeAddOpList(v, ArraySize(autoInc), autoInc, iLn);
309     if( aOp==0 ) break;
310     aOp[0].p2 = memId;
311     aOp[0].p3 = memId+2;
312     aOp[2].p3 = memId;
313     aOp[3].p1 = memId-1;
314     aOp[3].p3 = memId;
315     aOp[3].p5 = SQLITE_JUMPIFNULL;
316     aOp[4].p2 = memId+1;
317     aOp[5].p3 = memId;
318     aOp[6].p1 = memId;
319     aOp[7].p2 = memId+2;
320     aOp[7].p1 = memId;
321     aOp[10].p2 = memId;
322     if( pParse->nTab==0 ) pParse->nTab = 1;
323   }
324 }
325 
326 /*
327 ** Update the maximum rowid for an autoincrement calculation.
328 **
329 ** This routine should be called when the regRowid register holds a
330 ** new rowid that is about to be inserted.  If that new rowid is
331 ** larger than the maximum rowid in the memId memory cell, then the
332 ** memory cell is updated.
333 */
334 static void autoIncStep(Parse *pParse, int memId, int regRowid){
335   if( memId>0 ){
336     sqlite3VdbeAddOp2(pParse->pVdbe, OP_MemMax, memId, regRowid);
337   }
338 }
339 
340 /*
341 ** This routine generates the code needed to write autoincrement
342 ** maximum rowid values back into the sqlite_sequence register.
343 ** Every statement that might do an INSERT into an autoincrement
344 ** table (either directly or through triggers) needs to call this
345 ** routine just before the "exit" code.
346 */
347 static SQLITE_NOINLINE void autoIncrementEnd(Parse *pParse){
348   AutoincInfo *p;
349   Vdbe *v = pParse->pVdbe;
350   sqlite3 *db = pParse->db;
351 
352   assert( v );
353   for(p = pParse->pAinc; p; p = p->pNext){
354     static const int iLn = VDBE_OFFSET_LINENO(2);
355     static const VdbeOpList autoIncEnd[] = {
356       /* 0 */ {OP_NotNull,     0, 2, 0},
357       /* 1 */ {OP_NewRowid,    0, 0, 0},
358       /* 2 */ {OP_MakeRecord,  0, 2, 0},
359       /* 3 */ {OP_Insert,      0, 0, 0},
360       /* 4 */ {OP_Close,       0, 0, 0}
361     };
362     VdbeOp *aOp;
363     Db *pDb = &db->aDb[p->iDb];
364     int iRec;
365     int memId = p->regCtr;
366 
367     iRec = sqlite3GetTempReg(pParse);
368     assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
369     sqlite3VdbeAddOp3(v, OP_Le, memId+2, sqlite3VdbeCurrentAddr(v)+7, memId);
370     VdbeCoverage(v);
371     sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenWrite);
372     aOp = sqlite3VdbeAddOpList(v, ArraySize(autoIncEnd), autoIncEnd, iLn);
373     if( aOp==0 ) break;
374     aOp[0].p1 = memId+1;
375     aOp[1].p2 = memId+1;
376     aOp[2].p1 = memId-1;
377     aOp[2].p3 = iRec;
378     aOp[3].p2 = iRec;
379     aOp[3].p3 = memId+1;
380     aOp[3].p5 = OPFLAG_APPEND;
381     sqlite3ReleaseTempReg(pParse, iRec);
382   }
383 }
384 void sqlite3AutoincrementEnd(Parse *pParse){
385   if( pParse->pAinc ) autoIncrementEnd(pParse);
386 }
387 #else
388 /*
389 ** If SQLITE_OMIT_AUTOINCREMENT is defined, then the three routines
390 ** above are all no-ops
391 */
392 # define autoIncBegin(A,B,C) (0)
393 # define autoIncStep(A,B,C)
394 #endif /* SQLITE_OMIT_AUTOINCREMENT */
395 
396 
397 /* Forward declaration */
398 static int xferOptimization(
399   Parse *pParse,        /* Parser context */
400   Table *pDest,         /* The table we are inserting into */
401   Select *pSelect,      /* A SELECT statement to use as the data source */
402   int onError,          /* How to handle constraint errors */
403   int iDbDest           /* The database of pDest */
404 );
405 
406 /*
407 ** This routine is called to handle SQL of the following forms:
408 **
409 **    insert into TABLE (IDLIST) values(EXPRLIST),(EXPRLIST),...
410 **    insert into TABLE (IDLIST) select
411 **    insert into TABLE (IDLIST) default values
412 **
413 ** The IDLIST following the table name is always optional.  If omitted,
414 ** then a list of all (non-hidden) columns for the table is substituted.
415 ** The IDLIST appears in the pColumn parameter.  pColumn is NULL if IDLIST
416 ** is omitted.
417 **
418 ** For the pSelect parameter holds the values to be inserted for the
419 ** first two forms shown above.  A VALUES clause is really just short-hand
420 ** for a SELECT statement that omits the FROM clause and everything else
421 ** that follows.  If the pSelect parameter is NULL, that means that the
422 ** DEFAULT VALUES form of the INSERT statement is intended.
423 **
424 ** The code generated follows one of four templates.  For a simple
425 ** insert with data coming from a single-row VALUES clause, the code executes
426 ** once straight down through.  Pseudo-code follows (we call this
427 ** the "1st template"):
428 **
429 **         open write cursor to <table> and its indices
430 **         put VALUES clause expressions into registers
431 **         write the resulting record into <table>
432 **         cleanup
433 **
434 ** The three remaining templates assume the statement is of the form
435 **
436 **   INSERT INTO <table> SELECT ...
437 **
438 ** If the SELECT clause is of the restricted form "SELECT * FROM <table2>" -
439 ** in other words if the SELECT pulls all columns from a single table
440 ** and there is no WHERE or LIMIT or GROUP BY or ORDER BY clauses, and
441 ** if <table2> and <table1> are distinct tables but have identical
442 ** schemas, including all the same indices, then a special optimization
443 ** is invoked that copies raw records from <table2> over to <table1>.
444 ** See the xferOptimization() function for the implementation of this
445 ** template.  This is the 2nd template.
446 **
447 **         open a write cursor to <table>
448 **         open read cursor on <table2>
449 **         transfer all records in <table2> over to <table>
450 **         close cursors
451 **         foreach index on <table>
452 **           open a write cursor on the <table> index
453 **           open a read cursor on the corresponding <table2> index
454 **           transfer all records from the read to the write cursors
455 **           close cursors
456 **         end foreach
457 **
458 ** The 3rd template is for when the second template does not apply
459 ** and the SELECT clause does not read from <table> at any time.
460 ** The generated code follows this template:
461 **
462 **         X <- A
463 **         goto B
464 **      A: setup for the SELECT
465 **         loop over the rows in the SELECT
466 **           load values into registers R..R+n
467 **           yield X
468 **         end loop
469 **         cleanup after the SELECT
470 **         end-coroutine X
471 **      B: open write cursor to <table> and its indices
472 **      C: yield X, at EOF goto D
473 **         insert the select result into <table> from R..R+n
474 **         goto C
475 **      D: cleanup
476 **
477 ** The 4th template is used if the insert statement takes its
478 ** values from a SELECT but the data is being inserted into a table
479 ** that is also read as part of the SELECT.  In the third form,
480 ** we have to use an intermediate table to store the results of
481 ** the select.  The template is like this:
482 **
483 **         X <- A
484 **         goto B
485 **      A: setup for the SELECT
486 **         loop over the tables in the SELECT
487 **           load value into register R..R+n
488 **           yield X
489 **         end loop
490 **         cleanup after the SELECT
491 **         end co-routine R
492 **      B: open temp table
493 **      L: yield X, at EOF goto M
494 **         insert row from R..R+n into temp table
495 **         goto L
496 **      M: open write cursor to <table> and its indices
497 **         rewind temp table
498 **      C: loop over rows of intermediate table
499 **           transfer values form intermediate table into <table>
500 **         end loop
501 **      D: cleanup
502 */
503 void sqlite3Insert(
504   Parse *pParse,        /* Parser context */
505   SrcList *pTabList,    /* Name of table into which we are inserting */
506   Select *pSelect,      /* A SELECT statement to use as the data source */
507   IdList *pColumn,      /* Column names corresponding to IDLIST. */
508   int onError,          /* How to handle constraint errors */
509   Upsert *pUpsert       /* ON CONFLICT clauses for upsert, or NULL */
510 ){
511   sqlite3 *db;          /* The main database structure */
512   Table *pTab;          /* The table to insert into.  aka TABLE */
513   int i, j;             /* Loop counters */
514   Vdbe *v;              /* Generate code into this virtual machine */
515   Index *pIdx;          /* For looping over indices of the table */
516   int nColumn;          /* Number of columns in the data */
517   int nHidden = 0;      /* Number of hidden columns if TABLE is virtual */
518   int iDataCur = 0;     /* VDBE cursor that is the main data repository */
519   int iIdxCur = 0;      /* First index cursor */
520   int ipkColumn = -1;   /* Column that is the INTEGER PRIMARY KEY */
521   int endOfLoop;        /* Label for the end of the insertion loop */
522   int srcTab = 0;       /* Data comes from this temporary cursor if >=0 */
523   int addrInsTop = 0;   /* Jump to label "D" */
524   int addrCont = 0;     /* Top of insert loop. Label "C" in templates 3 and 4 */
525   SelectDest dest;      /* Destination for SELECT on rhs of INSERT */
526   int iDb;              /* Index of database holding TABLE */
527   u8 useTempTable = 0;  /* Store SELECT results in intermediate table */
528   u8 appendFlag = 0;    /* True if the insert is likely to be an append */
529   u8 withoutRowid;      /* 0 for normal table.  1 for WITHOUT ROWID table */
530   u8 bIdListInOrder;    /* True if IDLIST is in table order */
531   ExprList *pList = 0;  /* List of VALUES() to be inserted  */
532 
533   /* Register allocations */
534   int regFromSelect = 0;/* Base register for data coming from SELECT */
535   int regAutoinc = 0;   /* Register holding the AUTOINCREMENT counter */
536   int regRowCount = 0;  /* Memory cell used for the row counter */
537   int regIns;           /* Block of regs holding rowid+data being inserted */
538   int regRowid;         /* registers holding insert rowid */
539   int regData;          /* register holding first column to insert */
540   int *aRegIdx = 0;     /* One register allocated to each index */
541 
542 #ifndef SQLITE_OMIT_TRIGGER
543   int isView;                 /* True if attempting to insert into a view */
544   Trigger *pTrigger;          /* List of triggers on pTab, if required */
545   int tmask;                  /* Mask of trigger times */
546 #endif
547 
548   db = pParse->db;
549   if( pParse->nErr || db->mallocFailed ){
550     goto insert_cleanup;
551   }
552   dest.iSDParm = 0;  /* Suppress a harmless compiler warning */
553 
554   /* If the Select object is really just a simple VALUES() list with a
555   ** single row (the common case) then keep that one row of values
556   ** and discard the other (unused) parts of the pSelect object
557   */
558   if( pSelect && (pSelect->selFlags & SF_Values)!=0 && pSelect->pPrior==0 ){
559     pList = pSelect->pEList;
560     pSelect->pEList = 0;
561     sqlite3SelectDelete(db, pSelect);
562     pSelect = 0;
563   }
564 
565   /* Locate the table into which we will be inserting new information.
566   */
567   assert( pTabList->nSrc==1 );
568   pTab = sqlite3SrcListLookup(pParse, pTabList);
569   if( pTab==0 ){
570     goto insert_cleanup;
571   }
572   iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
573   assert( iDb<db->nDb );
574   if( sqlite3AuthCheck(pParse, SQLITE_INSERT, pTab->zName, 0,
575                        db->aDb[iDb].zDbSName) ){
576     goto insert_cleanup;
577   }
578   withoutRowid = !HasRowid(pTab);
579 
580   /* Figure out if we have any triggers and if the table being
581   ** inserted into is a view
582   */
583 #ifndef SQLITE_OMIT_TRIGGER
584   pTrigger = sqlite3TriggersExist(pParse, pTab, TK_INSERT, 0, &tmask);
585   isView = pTab->pSelect!=0;
586 #else
587 # define pTrigger 0
588 # define tmask 0
589 # define isView 0
590 #endif
591 #ifdef SQLITE_OMIT_VIEW
592 # undef isView
593 # define isView 0
594 #endif
595   assert( (pTrigger && tmask) || (pTrigger==0 && tmask==0) );
596 
597   /* If pTab is really a view, make sure it has been initialized.
598   ** ViewGetColumnNames() is a no-op if pTab is not a view.
599   */
600   if( sqlite3ViewGetColumnNames(pParse, pTab) ){
601     goto insert_cleanup;
602   }
603 
604   /* Cannot insert into a read-only table.
605   */
606   if( sqlite3IsReadOnly(pParse, pTab, tmask) ){
607     goto insert_cleanup;
608   }
609 
610   /* Allocate a VDBE
611   */
612   v = sqlite3GetVdbe(pParse);
613   if( v==0 ) goto insert_cleanup;
614   if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
615   sqlite3BeginWriteOperation(pParse, pSelect || pTrigger, iDb);
616 
617 #ifndef SQLITE_OMIT_XFER_OPT
618   /* If the statement is of the form
619   **
620   **       INSERT INTO <table1> SELECT * FROM <table2>;
621   **
622   ** Then special optimizations can be applied that make the transfer
623   ** very fast and which reduce fragmentation of indices.
624   **
625   ** This is the 2nd template.
626   */
627   if( pColumn==0 && xferOptimization(pParse, pTab, pSelect, onError, iDb) ){
628     assert( !pTrigger );
629     assert( pList==0 );
630     goto insert_end;
631   }
632 #endif /* SQLITE_OMIT_XFER_OPT */
633 
634   /* If this is an AUTOINCREMENT table, look up the sequence number in the
635   ** sqlite_sequence table and store it in memory cell regAutoinc.
636   */
637   regAutoinc = autoIncBegin(pParse, iDb, pTab);
638 
639   /* Allocate registers for holding the rowid of the new row,
640   ** the content of the new row, and the assembled row record.
641   */
642   regRowid = regIns = pParse->nMem+1;
643   pParse->nMem += pTab->nCol + 1;
644   if( IsVirtual(pTab) ){
645     regRowid++;
646     pParse->nMem++;
647   }
648   regData = regRowid+1;
649 
650   /* If the INSERT statement included an IDLIST term, then make sure
651   ** all elements of the IDLIST really are columns of the table and
652   ** remember the column indices.
653   **
654   ** If the table has an INTEGER PRIMARY KEY column and that column
655   ** is named in the IDLIST, then record in the ipkColumn variable
656   ** the index into IDLIST of the primary key column.  ipkColumn is
657   ** the index of the primary key as it appears in IDLIST, not as
658   ** is appears in the original table.  (The index of the INTEGER
659   ** PRIMARY KEY in the original table is pTab->iPKey.)
660   */
661   bIdListInOrder = (pTab->tabFlags & TF_OOOHidden)==0;
662   if( pColumn ){
663     for(i=0; i<pColumn->nId; i++){
664       pColumn->a[i].idx = -1;
665     }
666     for(i=0; i<pColumn->nId; i++){
667       for(j=0; j<pTab->nCol; j++){
668         if( sqlite3StrICmp(pColumn->a[i].zName, pTab->aCol[j].zName)==0 ){
669           pColumn->a[i].idx = j;
670           if( i!=j ) bIdListInOrder = 0;
671           if( j==pTab->iPKey ){
672             ipkColumn = i;  assert( !withoutRowid );
673           }
674           break;
675         }
676       }
677       if( j>=pTab->nCol ){
678         if( sqlite3IsRowid(pColumn->a[i].zName) && !withoutRowid ){
679           ipkColumn = i;
680           bIdListInOrder = 0;
681         }else{
682           sqlite3ErrorMsg(pParse, "table %S has no column named %s",
683               pTabList, 0, pColumn->a[i].zName);
684           pParse->checkSchema = 1;
685           goto insert_cleanup;
686         }
687       }
688     }
689   }
690 
691   /* Figure out how many columns of data are supplied.  If the data
692   ** is coming from a SELECT statement, then generate a co-routine that
693   ** produces a single row of the SELECT on each invocation.  The
694   ** co-routine is the common header to the 3rd and 4th templates.
695   */
696   if( pSelect ){
697     /* Data is coming from a SELECT or from a multi-row VALUES clause.
698     ** Generate a co-routine to run the SELECT. */
699     int regYield;       /* Register holding co-routine entry-point */
700     int addrTop;        /* Top of the co-routine */
701     int rc;             /* Result code */
702 
703     regYield = ++pParse->nMem;
704     addrTop = sqlite3VdbeCurrentAddr(v) + 1;
705     sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, addrTop);
706     sqlite3SelectDestInit(&dest, SRT_Coroutine, regYield);
707     dest.iSdst = bIdListInOrder ? regData : 0;
708     dest.nSdst = pTab->nCol;
709     rc = sqlite3Select(pParse, pSelect, &dest);
710     regFromSelect = dest.iSdst;
711     if( rc || db->mallocFailed || pParse->nErr ) goto insert_cleanup;
712     sqlite3VdbeEndCoroutine(v, regYield);
713     sqlite3VdbeJumpHere(v, addrTop - 1);                       /* label B: */
714     assert( pSelect->pEList );
715     nColumn = pSelect->pEList->nExpr;
716 
717     /* Set useTempTable to TRUE if the result of the SELECT statement
718     ** should be written into a temporary table (template 4).  Set to
719     ** FALSE if each output row of the SELECT can be written directly into
720     ** the destination table (template 3).
721     **
722     ** A temp table must be used if the table being updated is also one
723     ** of the tables being read by the SELECT statement.  Also use a
724     ** temp table in the case of row triggers.
725     */
726     if( pTrigger || readsTable(pParse, iDb, pTab) ){
727       useTempTable = 1;
728     }
729 
730     if( useTempTable ){
731       /* Invoke the coroutine to extract information from the SELECT
732       ** and add it to a transient table srcTab.  The code generated
733       ** here is from the 4th template:
734       **
735       **      B: open temp table
736       **      L: yield X, goto M at EOF
737       **         insert row from R..R+n into temp table
738       **         goto L
739       **      M: ...
740       */
741       int regRec;          /* Register to hold packed record */
742       int regTempRowid;    /* Register to hold temp table ROWID */
743       int addrL;           /* Label "L" */
744 
745       srcTab = pParse->nTab++;
746       regRec = sqlite3GetTempReg(pParse);
747       regTempRowid = sqlite3GetTempReg(pParse);
748       sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
749       addrL = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm); VdbeCoverage(v);
750       sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
751       sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regTempRowid);
752       sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regTempRowid);
753       sqlite3VdbeGoto(v, addrL);
754       sqlite3VdbeJumpHere(v, addrL);
755       sqlite3ReleaseTempReg(pParse, regRec);
756       sqlite3ReleaseTempReg(pParse, regTempRowid);
757     }
758   }else{
759     /* This is the case if the data for the INSERT is coming from a
760     ** single-row VALUES clause
761     */
762     NameContext sNC;
763     memset(&sNC, 0, sizeof(sNC));
764     sNC.pParse = pParse;
765     srcTab = -1;
766     assert( useTempTable==0 );
767     if( pList ){
768       nColumn = pList->nExpr;
769       if( sqlite3ResolveExprListNames(&sNC, pList) ){
770         goto insert_cleanup;
771       }
772     }else{
773       nColumn = 0;
774     }
775   }
776 
777   /* If there is no IDLIST term but the table has an integer primary
778   ** key, the set the ipkColumn variable to the integer primary key
779   ** column index in the original table definition.
780   */
781   if( pColumn==0 && nColumn>0 ){
782     ipkColumn = pTab->iPKey;
783   }
784 
785   /* Make sure the number of columns in the source data matches the number
786   ** of columns to be inserted into the table.
787   */
788   for(i=0; i<pTab->nCol; i++){
789     nHidden += (IsHiddenColumn(&pTab->aCol[i]) ? 1 : 0);
790   }
791   if( pColumn==0 && nColumn && nColumn!=(pTab->nCol-nHidden) ){
792     sqlite3ErrorMsg(pParse,
793        "table %S has %d columns but %d values were supplied",
794        pTabList, 0, pTab->nCol-nHidden, nColumn);
795     goto insert_cleanup;
796   }
797   if( pColumn!=0 && nColumn!=pColumn->nId ){
798     sqlite3ErrorMsg(pParse, "%d values for %d columns", nColumn, pColumn->nId);
799     goto insert_cleanup;
800   }
801 
802   /* Initialize the count of rows to be inserted
803   */
804   if( (db->flags & SQLITE_CountRows)!=0
805    && !pParse->nested
806    && !pParse->pTriggerTab
807   ){
808     regRowCount = ++pParse->nMem;
809     sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
810   }
811 
812   /* If this is not a view, open the table and and all indices */
813   if( !isView ){
814     int nIdx;
815     nIdx = sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, 0, -1, 0,
816                                       &iDataCur, &iIdxCur);
817     aRegIdx = sqlite3DbMallocRawNN(db, sizeof(int)*(nIdx+1));
818     if( aRegIdx==0 ){
819       goto insert_cleanup;
820     }
821     for(i=0, pIdx=pTab->pIndex; i<nIdx; pIdx=pIdx->pNext, i++){
822       assert( pIdx );
823       aRegIdx[i] = ++pParse->nMem;
824       pParse->nMem += pIdx->nColumn;
825     }
826   }
827 #ifndef SQLITE_OMIT_UPSERT
828   if( pUpsert ){
829     pTabList->a[0].iCursor = iDataCur;
830     pUpsert->pUpsertSrc = pTabList;
831     pUpsert->regData = regData;
832     pUpsert->iDataCur = iDataCur;
833     pUpsert->iIdxCur = iIdxCur;
834     if( pUpsert->pUpsertTarget ){
835       sqlite3UpsertAnalyzeTarget(pParse, pTabList, pUpsert);
836     }
837   }
838 #endif
839 
840 
841   /* This is the top of the main insertion loop */
842   if( useTempTable ){
843     /* This block codes the top of loop only.  The complete loop is the
844     ** following pseudocode (template 4):
845     **
846     **         rewind temp table, if empty goto D
847     **      C: loop over rows of intermediate table
848     **           transfer values form intermediate table into <table>
849     **         end loop
850     **      D: ...
851     */
852     addrInsTop = sqlite3VdbeAddOp1(v, OP_Rewind, srcTab); VdbeCoverage(v);
853     addrCont = sqlite3VdbeCurrentAddr(v);
854   }else if( pSelect ){
855     /* This block codes the top of loop only.  The complete loop is the
856     ** following pseudocode (template 3):
857     **
858     **      C: yield X, at EOF goto D
859     **         insert the select result into <table> from R..R+n
860     **         goto C
861     **      D: ...
862     */
863     addrInsTop = addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
864     VdbeCoverage(v);
865   }
866 
867   /* Run the BEFORE and INSTEAD OF triggers, if there are any
868   */
869   endOfLoop = sqlite3VdbeMakeLabel(v);
870   if( tmask & TRIGGER_BEFORE ){
871     int regCols = sqlite3GetTempRange(pParse, pTab->nCol+1);
872 
873     /* build the NEW.* reference row.  Note that if there is an INTEGER
874     ** PRIMARY KEY into which a NULL is being inserted, that NULL will be
875     ** translated into a unique ID for the row.  But on a BEFORE trigger,
876     ** we do not know what the unique ID will be (because the insert has
877     ** not happened yet) so we substitute a rowid of -1
878     */
879     if( ipkColumn<0 ){
880       sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
881     }else{
882       int addr1;
883       assert( !withoutRowid );
884       if( useTempTable ){
885         sqlite3VdbeAddOp3(v, OP_Column, srcTab, ipkColumn, regCols);
886       }else{
887         assert( pSelect==0 );  /* Otherwise useTempTable is true */
888         sqlite3ExprCode(pParse, pList->a[ipkColumn].pExpr, regCols);
889       }
890       addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regCols); VdbeCoverage(v);
891       sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
892       sqlite3VdbeJumpHere(v, addr1);
893       sqlite3VdbeAddOp1(v, OP_MustBeInt, regCols); VdbeCoverage(v);
894     }
895 
896     /* Cannot have triggers on a virtual table. If it were possible,
897     ** this block would have to account for hidden column.
898     */
899     assert( !IsVirtual(pTab) );
900 
901     /* Create the new column data
902     */
903     for(i=j=0; i<pTab->nCol; i++){
904       if( pColumn ){
905         for(j=0; j<pColumn->nId; j++){
906           if( pColumn->a[j].idx==i ) break;
907         }
908       }
909       if( (!useTempTable && !pList) || (pColumn && j>=pColumn->nId)
910             || (pColumn==0 && IsOrdinaryHiddenColumn(&pTab->aCol[i])) ){
911         sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regCols+i+1);
912       }else if( useTempTable ){
913         sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, regCols+i+1);
914       }else{
915         assert( pSelect==0 ); /* Otherwise useTempTable is true */
916         sqlite3ExprCodeAndCache(pParse, pList->a[j].pExpr, regCols+i+1);
917       }
918       if( pColumn==0 && !IsOrdinaryHiddenColumn(&pTab->aCol[i]) ) j++;
919     }
920 
921     /* If this is an INSERT on a view with an INSTEAD OF INSERT trigger,
922     ** do not attempt any conversions before assembling the record.
923     ** If this is a real table, attempt conversions as required by the
924     ** table column affinities.
925     */
926     if( !isView ){
927       sqlite3TableAffinity(v, pTab, regCols+1);
928     }
929 
930     /* Fire BEFORE or INSTEAD OF triggers */
931     sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_BEFORE,
932         pTab, regCols-pTab->nCol-1, onError, endOfLoop);
933 
934     sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol+1);
935   }
936 
937   /* Compute the content of the next row to insert into a range of
938   ** registers beginning at regIns.
939   */
940   if( !isView ){
941     if( IsVirtual(pTab) ){
942       /* The row that the VUpdate opcode will delete: none */
943       sqlite3VdbeAddOp2(v, OP_Null, 0, regIns);
944     }
945     if( ipkColumn>=0 ){
946       if( useTempTable ){
947         sqlite3VdbeAddOp3(v, OP_Column, srcTab, ipkColumn, regRowid);
948       }else if( pSelect ){
949         sqlite3VdbeAddOp2(v, OP_Copy, regFromSelect+ipkColumn, regRowid);
950       }else{
951         VdbeOp *pOp;
952         sqlite3ExprCode(pParse, pList->a[ipkColumn].pExpr, regRowid);
953         pOp = sqlite3VdbeGetOp(v, -1);
954         assert( pOp!=0 );
955         if( pOp->opcode==OP_Null && !IsVirtual(pTab) ){
956           appendFlag = 1;
957           pOp->opcode = OP_NewRowid;
958           pOp->p1 = iDataCur;
959           pOp->p2 = regRowid;
960           pOp->p3 = regAutoinc;
961         }
962       }
963       /* If the PRIMARY KEY expression is NULL, then use OP_NewRowid
964       ** to generate a unique primary key value.
965       */
966       if( !appendFlag ){
967         int addr1;
968         if( !IsVirtual(pTab) ){
969           addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regRowid); VdbeCoverage(v);
970           sqlite3VdbeAddOp3(v, OP_NewRowid, iDataCur, regRowid, regAutoinc);
971           sqlite3VdbeJumpHere(v, addr1);
972         }else{
973           addr1 = sqlite3VdbeCurrentAddr(v);
974           sqlite3VdbeAddOp2(v, OP_IsNull, regRowid, addr1+2); VdbeCoverage(v);
975         }
976         sqlite3VdbeAddOp1(v, OP_MustBeInt, regRowid); VdbeCoverage(v);
977       }
978     }else if( IsVirtual(pTab) || withoutRowid ){
979       sqlite3VdbeAddOp2(v, OP_Null, 0, regRowid);
980     }else{
981       sqlite3VdbeAddOp3(v, OP_NewRowid, iDataCur, regRowid, regAutoinc);
982       appendFlag = 1;
983     }
984     autoIncStep(pParse, regAutoinc, regRowid);
985 
986     /* Compute data for all columns of the new entry, beginning
987     ** with the first column.
988     */
989     nHidden = 0;
990     for(i=0; i<pTab->nCol; i++){
991       int iRegStore = regRowid+1+i;
992       if( i==pTab->iPKey ){
993         /* The value of the INTEGER PRIMARY KEY column is always a NULL.
994         ** Whenever this column is read, the rowid will be substituted
995         ** in its place.  Hence, fill this column with a NULL to avoid
996         ** taking up data space with information that will never be used.
997         ** As there may be shallow copies of this value, make it a soft-NULL */
998         sqlite3VdbeAddOp1(v, OP_SoftNull, iRegStore);
999         continue;
1000       }
1001       if( pColumn==0 ){
1002         if( IsHiddenColumn(&pTab->aCol[i]) ){
1003           j = -1;
1004           nHidden++;
1005         }else{
1006           j = i - nHidden;
1007         }
1008       }else{
1009         for(j=0; j<pColumn->nId; j++){
1010           if( pColumn->a[j].idx==i ) break;
1011         }
1012       }
1013       if( j<0 || nColumn==0 || (pColumn && j>=pColumn->nId) ){
1014         sqlite3ExprCodeFactorable(pParse, pTab->aCol[i].pDflt, iRegStore);
1015       }else if( useTempTable ){
1016         sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, iRegStore);
1017       }else if( pSelect ){
1018         if( regFromSelect!=regData ){
1019           sqlite3VdbeAddOp2(v, OP_SCopy, regFromSelect+j, iRegStore);
1020         }
1021       }else{
1022         sqlite3ExprCode(pParse, pList->a[j].pExpr, iRegStore);
1023       }
1024     }
1025 
1026     /* Generate code to check constraints and generate index keys and
1027     ** do the insertion.
1028     */
1029 #ifndef SQLITE_OMIT_VIRTUALTABLE
1030     if( IsVirtual(pTab) ){
1031       const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
1032       sqlite3VtabMakeWritable(pParse, pTab);
1033       sqlite3VdbeAddOp4(v, OP_VUpdate, 1, pTab->nCol+2, regIns, pVTab, P4_VTAB);
1034       sqlite3VdbeChangeP5(v, onError==OE_Default ? OE_Abort : onError);
1035       sqlite3MayAbort(pParse);
1036     }else
1037 #endif
1038     {
1039       int isReplace;    /* Set to true if constraints may cause a replace */
1040       int bUseSeek;     /* True to use OPFLAG_SEEKRESULT */
1041       sqlite3GenerateConstraintChecks(pParse, pTab, aRegIdx, iDataCur, iIdxCur,
1042           regIns, 0, ipkColumn>=0, onError, endOfLoop, &isReplace, 0, pUpsert
1043       );
1044       sqlite3FkCheck(pParse, pTab, 0, regIns, 0, 0);
1045 
1046       /* Set the OPFLAG_USESEEKRESULT flag if either (a) there are no REPLACE
1047       ** constraints or (b) there are no triggers and this table is not a
1048       ** parent table in a foreign key constraint. It is safe to set the
1049       ** flag in the second case as if any REPLACE constraint is hit, an
1050       ** OP_Delete or OP_IdxDelete instruction will be executed on each
1051       ** cursor that is disturbed. And these instructions both clear the
1052       ** VdbeCursor.seekResult variable, disabling the OPFLAG_USESEEKRESULT
1053       ** functionality.  */
1054       bUseSeek = (isReplace==0 || (pTrigger==0 &&
1055           ((db->flags & SQLITE_ForeignKeys)==0 || sqlite3FkReferences(pTab)==0)
1056       ));
1057       sqlite3CompleteInsertion(pParse, pTab, iDataCur, iIdxCur,
1058           regIns, aRegIdx, 0, appendFlag, bUseSeek
1059       );
1060     }
1061   }
1062 
1063   /* Update the count of rows that are inserted
1064   */
1065   if( regRowCount ){
1066     sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
1067   }
1068 
1069   if( pTrigger ){
1070     /* Code AFTER triggers */
1071     sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_AFTER,
1072         pTab, regData-2-pTab->nCol, onError, endOfLoop);
1073   }
1074 
1075   /* The bottom of the main insertion loop, if the data source
1076   ** is a SELECT statement.
1077   */
1078   sqlite3VdbeResolveLabel(v, endOfLoop);
1079   if( useTempTable ){
1080     sqlite3VdbeAddOp2(v, OP_Next, srcTab, addrCont); VdbeCoverage(v);
1081     sqlite3VdbeJumpHere(v, addrInsTop);
1082     sqlite3VdbeAddOp1(v, OP_Close, srcTab);
1083   }else if( pSelect ){
1084     sqlite3VdbeGoto(v, addrCont);
1085     sqlite3VdbeJumpHere(v, addrInsTop);
1086   }
1087 
1088 insert_end:
1089   /* Update the sqlite_sequence table by storing the content of the
1090   ** maximum rowid counter values recorded while inserting into
1091   ** autoincrement tables.
1092   */
1093   if( pParse->nested==0 && pParse->pTriggerTab==0 ){
1094     sqlite3AutoincrementEnd(pParse);
1095   }
1096 
1097   /*
1098   ** Return the number of rows inserted. If this routine is
1099   ** generating code because of a call to sqlite3NestedParse(), do not
1100   ** invoke the callback function.
1101   */
1102   if( regRowCount ){
1103     sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
1104     sqlite3VdbeSetNumCols(v, 1);
1105     sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows inserted", SQLITE_STATIC);
1106   }
1107 
1108 insert_cleanup:
1109   sqlite3SrcListDelete(db, pTabList);
1110   sqlite3ExprListDelete(db, pList);
1111   sqlite3UpsertDelete(db, pUpsert);
1112   sqlite3SelectDelete(db, pSelect);
1113   sqlite3IdListDelete(db, pColumn);
1114   sqlite3DbFree(db, aRegIdx);
1115 }
1116 
1117 /* Make sure "isView" and other macros defined above are undefined. Otherwise
1118 ** they may interfere with compilation of other functions in this file
1119 ** (or in another file, if this file becomes part of the amalgamation).  */
1120 #ifdef isView
1121  #undef isView
1122 #endif
1123 #ifdef pTrigger
1124  #undef pTrigger
1125 #endif
1126 #ifdef tmask
1127  #undef tmask
1128 #endif
1129 
1130 /*
1131 ** Meanings of bits in of pWalker->eCode for
1132 ** sqlite3ExprReferencesUpdatedColumn()
1133 */
1134 #define CKCNSTRNT_COLUMN   0x01    /* CHECK constraint uses a changing column */
1135 #define CKCNSTRNT_ROWID    0x02    /* CHECK constraint references the ROWID */
1136 
1137 /* This is the Walker callback from sqlite3ExprReferencesUpdatedColumn().
1138 *  Set bit 0x01 of pWalker->eCode if pWalker->eCode to 0 and if this
1139 ** expression node references any of the
1140 ** columns that are being modifed by an UPDATE statement.
1141 */
1142 static int checkConstraintExprNode(Walker *pWalker, Expr *pExpr){
1143   if( pExpr->op==TK_COLUMN ){
1144     assert( pExpr->iColumn>=0 || pExpr->iColumn==-1 );
1145     if( pExpr->iColumn>=0 ){
1146       if( pWalker->u.aiCol[pExpr->iColumn]>=0 ){
1147         pWalker->eCode |= CKCNSTRNT_COLUMN;
1148       }
1149     }else{
1150       pWalker->eCode |= CKCNSTRNT_ROWID;
1151     }
1152   }
1153   return WRC_Continue;
1154 }
1155 
1156 /*
1157 ** pExpr is a CHECK constraint on a row that is being UPDATE-ed.  The
1158 ** only columns that are modified by the UPDATE are those for which
1159 ** aiChng[i]>=0, and also the ROWID is modified if chngRowid is true.
1160 **
1161 ** Return true if CHECK constraint pExpr uses any of the
1162 ** changing columns (or the rowid if it is changing).  In other words,
1163 ** return true if this CHECK constraint must be validated for
1164 ** the new row in the UPDATE statement.
1165 **
1166 ** 2018-09-15: pExpr might also be an expression for an index-on-expressions.
1167 ** The operation of this routine is the same - return true if an only if
1168 ** the expression uses one or more of columns identified by the second and
1169 ** third arguments.
1170 */
1171 int sqlite3ExprReferencesUpdatedColumn(
1172   Expr *pExpr,    /* The expression to be checked */
1173   int *aiChng,    /* aiChng[x]>=0 if column x changed by the UPDATE */
1174   int chngRowid   /* True if UPDATE changes the rowid */
1175 ){
1176   Walker w;
1177   memset(&w, 0, sizeof(w));
1178   w.eCode = 0;
1179   w.xExprCallback = checkConstraintExprNode;
1180   w.u.aiCol = aiChng;
1181   sqlite3WalkExpr(&w, pExpr);
1182   if( !chngRowid ){
1183     testcase( (w.eCode & CKCNSTRNT_ROWID)!=0 );
1184     w.eCode &= ~CKCNSTRNT_ROWID;
1185   }
1186   testcase( w.eCode==0 );
1187   testcase( w.eCode==CKCNSTRNT_COLUMN );
1188   testcase( w.eCode==CKCNSTRNT_ROWID );
1189   testcase( w.eCode==(CKCNSTRNT_ROWID|CKCNSTRNT_COLUMN) );
1190   return w.eCode!=0;
1191 }
1192 
1193 /*
1194 ** Generate code to do constraint checks prior to an INSERT or an UPDATE
1195 ** on table pTab.
1196 **
1197 ** The regNewData parameter is the first register in a range that contains
1198 ** the data to be inserted or the data after the update.  There will be
1199 ** pTab->nCol+1 registers in this range.  The first register (the one
1200 ** that regNewData points to) will contain the new rowid, or NULL in the
1201 ** case of a WITHOUT ROWID table.  The second register in the range will
1202 ** contain the content of the first table column.  The third register will
1203 ** contain the content of the second table column.  And so forth.
1204 **
1205 ** The regOldData parameter is similar to regNewData except that it contains
1206 ** the data prior to an UPDATE rather than afterwards.  regOldData is zero
1207 ** for an INSERT.  This routine can distinguish between UPDATE and INSERT by
1208 ** checking regOldData for zero.
1209 **
1210 ** For an UPDATE, the pkChng boolean is true if the true primary key (the
1211 ** rowid for a normal table or the PRIMARY KEY for a WITHOUT ROWID table)
1212 ** might be modified by the UPDATE.  If pkChng is false, then the key of
1213 ** the iDataCur content table is guaranteed to be unchanged by the UPDATE.
1214 **
1215 ** For an INSERT, the pkChng boolean indicates whether or not the rowid
1216 ** was explicitly specified as part of the INSERT statement.  If pkChng
1217 ** is zero, it means that the either rowid is computed automatically or
1218 ** that the table is a WITHOUT ROWID table and has no rowid.  On an INSERT,
1219 ** pkChng will only be true if the INSERT statement provides an integer
1220 ** value for either the rowid column or its INTEGER PRIMARY KEY alias.
1221 **
1222 ** The code generated by this routine will store new index entries into
1223 ** registers identified by aRegIdx[].  No index entry is created for
1224 ** indices where aRegIdx[i]==0.  The order of indices in aRegIdx[] is
1225 ** the same as the order of indices on the linked list of indices
1226 ** at pTab->pIndex.
1227 **
1228 ** The caller must have already opened writeable cursors on the main
1229 ** table and all applicable indices (that is to say, all indices for which
1230 ** aRegIdx[] is not zero).  iDataCur is the cursor for the main table when
1231 ** inserting or updating a rowid table, or the cursor for the PRIMARY KEY
1232 ** index when operating on a WITHOUT ROWID table.  iIdxCur is the cursor
1233 ** for the first index in the pTab->pIndex list.  Cursors for other indices
1234 ** are at iIdxCur+N for the N-th element of the pTab->pIndex list.
1235 **
1236 ** This routine also generates code to check constraints.  NOT NULL,
1237 ** CHECK, and UNIQUE constraints are all checked.  If a constraint fails,
1238 ** then the appropriate action is performed.  There are five possible
1239 ** actions: ROLLBACK, ABORT, FAIL, REPLACE, and IGNORE.
1240 **
1241 **  Constraint type  Action       What Happens
1242 **  ---------------  ----------   ----------------------------------------
1243 **  any              ROLLBACK     The current transaction is rolled back and
1244 **                                sqlite3_step() returns immediately with a
1245 **                                return code of SQLITE_CONSTRAINT.
1246 **
1247 **  any              ABORT        Back out changes from the current command
1248 **                                only (do not do a complete rollback) then
1249 **                                cause sqlite3_step() to return immediately
1250 **                                with SQLITE_CONSTRAINT.
1251 **
1252 **  any              FAIL         Sqlite3_step() returns immediately with a
1253 **                                return code of SQLITE_CONSTRAINT.  The
1254 **                                transaction is not rolled back and any
1255 **                                changes to prior rows are retained.
1256 **
1257 **  any              IGNORE       The attempt in insert or update the current
1258 **                                row is skipped, without throwing an error.
1259 **                                Processing continues with the next row.
1260 **                                (There is an immediate jump to ignoreDest.)
1261 **
1262 **  NOT NULL         REPLACE      The NULL value is replace by the default
1263 **                                value for that column.  If the default value
1264 **                                is NULL, the action is the same as ABORT.
1265 **
1266 **  UNIQUE           REPLACE      The other row that conflicts with the row
1267 **                                being inserted is removed.
1268 **
1269 **  CHECK            REPLACE      Illegal.  The results in an exception.
1270 **
1271 ** Which action to take is determined by the overrideError parameter.
1272 ** Or if overrideError==OE_Default, then the pParse->onError parameter
1273 ** is used.  Or if pParse->onError==OE_Default then the onError value
1274 ** for the constraint is used.
1275 */
1276 void sqlite3GenerateConstraintChecks(
1277   Parse *pParse,       /* The parser context */
1278   Table *pTab,         /* The table being inserted or updated */
1279   int *aRegIdx,        /* Use register aRegIdx[i] for index i.  0 for unused */
1280   int iDataCur,        /* Canonical data cursor (main table or PK index) */
1281   int iIdxCur,         /* First index cursor */
1282   int regNewData,      /* First register in a range holding values to insert */
1283   int regOldData,      /* Previous content.  0 for INSERTs */
1284   u8 pkChng,           /* Non-zero if the rowid or PRIMARY KEY changed */
1285   u8 overrideError,    /* Override onError to this if not OE_Default */
1286   int ignoreDest,      /* Jump to this label on an OE_Ignore resolution */
1287   int *pbMayReplace,   /* OUT: Set to true if constraint may cause a replace */
1288   int *aiChng,         /* column i is unchanged if aiChng[i]<0 */
1289   Upsert *pUpsert      /* ON CONFLICT clauses, if any.  NULL otherwise */
1290 ){
1291   Vdbe *v;             /* VDBE under constrution */
1292   Index *pIdx;         /* Pointer to one of the indices */
1293   Index *pPk = 0;      /* The PRIMARY KEY index */
1294   sqlite3 *db;         /* Database connection */
1295   int i;               /* loop counter */
1296   int ix;              /* Index loop counter */
1297   int nCol;            /* Number of columns */
1298   int onError;         /* Conflict resolution strategy */
1299   int addr1;           /* Address of jump instruction */
1300   int seenReplace = 0; /* True if REPLACE is used to resolve INT PK conflict */
1301   int nPkField;        /* Number of fields in PRIMARY KEY. 1 for ROWID tables */
1302   Index *pUpIdx = 0;   /* Index to which to apply the upsert */
1303   u8 isUpdate;         /* True if this is an UPDATE operation */
1304   u8 bAffinityDone = 0;  /* True if the OP_Affinity operation has been run */
1305   int upsertBypass = 0;  /* Address of Goto to bypass upsert subroutine */
1306   int upsertJump = 0;    /* Address of Goto that jumps into upsert subroutine */
1307   int ipkTop = 0;        /* Top of the IPK uniqueness check */
1308   int ipkBottom = 0;     /* OP_Goto at the end of the IPK uniqueness check */
1309 
1310   isUpdate = regOldData!=0;
1311   db = pParse->db;
1312   v = sqlite3GetVdbe(pParse);
1313   assert( v!=0 );
1314   assert( pTab->pSelect==0 );  /* This table is not a VIEW */
1315   nCol = pTab->nCol;
1316 
1317   /* pPk is the PRIMARY KEY index for WITHOUT ROWID tables and NULL for
1318   ** normal rowid tables.  nPkField is the number of key fields in the
1319   ** pPk index or 1 for a rowid table.  In other words, nPkField is the
1320   ** number of fields in the true primary key of the table. */
1321   if( HasRowid(pTab) ){
1322     pPk = 0;
1323     nPkField = 1;
1324   }else{
1325     pPk = sqlite3PrimaryKeyIndex(pTab);
1326     nPkField = pPk->nKeyCol;
1327   }
1328 
1329   /* Record that this module has started */
1330   VdbeModuleComment((v, "BEGIN: GenCnstCks(%d,%d,%d,%d,%d)",
1331                      iDataCur, iIdxCur, regNewData, regOldData, pkChng));
1332 
1333   /* Test all NOT NULL constraints.
1334   */
1335   for(i=0; i<nCol; i++){
1336     if( i==pTab->iPKey ){
1337       continue;        /* ROWID is never NULL */
1338     }
1339     if( aiChng && aiChng[i]<0 ){
1340       /* Don't bother checking for NOT NULL on columns that do not change */
1341       continue;
1342     }
1343     onError = pTab->aCol[i].notNull;
1344     if( onError==OE_None ) continue;  /* This column is allowed to be NULL */
1345     if( overrideError!=OE_Default ){
1346       onError = overrideError;
1347     }else if( onError==OE_Default ){
1348       onError = OE_Abort;
1349     }
1350     if( onError==OE_Replace && pTab->aCol[i].pDflt==0 ){
1351       onError = OE_Abort;
1352     }
1353     assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
1354         || onError==OE_Ignore || onError==OE_Replace );
1355     switch( onError ){
1356       case OE_Abort:
1357         sqlite3MayAbort(pParse);
1358         /* Fall through */
1359       case OE_Rollback:
1360       case OE_Fail: {
1361         char *zMsg = sqlite3MPrintf(db, "%s.%s", pTab->zName,
1362                                     pTab->aCol[i].zName);
1363         sqlite3VdbeAddOp3(v, OP_HaltIfNull, SQLITE_CONSTRAINT_NOTNULL, onError,
1364                           regNewData+1+i);
1365         sqlite3VdbeAppendP4(v, zMsg, P4_DYNAMIC);
1366         sqlite3VdbeChangeP5(v, P5_ConstraintNotNull);
1367         VdbeCoverage(v);
1368         break;
1369       }
1370       case OE_Ignore: {
1371         sqlite3VdbeAddOp2(v, OP_IsNull, regNewData+1+i, ignoreDest);
1372         VdbeCoverage(v);
1373         break;
1374       }
1375       default: {
1376         assert( onError==OE_Replace );
1377         addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regNewData+1+i);
1378            VdbeCoverage(v);
1379         sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regNewData+1+i);
1380         sqlite3VdbeJumpHere(v, addr1);
1381         break;
1382       }
1383     }
1384   }
1385 
1386   /* Test all CHECK constraints
1387   */
1388 #ifndef SQLITE_OMIT_CHECK
1389   if( pTab->pCheck && (db->flags & SQLITE_IgnoreChecks)==0 ){
1390     ExprList *pCheck = pTab->pCheck;
1391     pParse->iSelfTab = -(regNewData+1);
1392     onError = overrideError!=OE_Default ? overrideError : OE_Abort;
1393     for(i=0; i<pCheck->nExpr; i++){
1394       int allOk;
1395       Expr *pExpr = pCheck->a[i].pExpr;
1396       if( aiChng
1397        && !sqlite3ExprReferencesUpdatedColumn(pExpr, aiChng, pkChng)
1398       ){
1399         /* The check constraints do not reference any of the columns being
1400         ** updated so there is no point it verifying the check constraint */
1401         continue;
1402       }
1403       allOk = sqlite3VdbeMakeLabel(v);
1404       sqlite3VdbeVerifyAbortable(v, onError);
1405       sqlite3ExprIfTrue(pParse, pExpr, allOk, SQLITE_JUMPIFNULL);
1406       if( onError==OE_Ignore ){
1407         sqlite3VdbeGoto(v, ignoreDest);
1408       }else{
1409         char *zName = pCheck->a[i].zName;
1410         if( zName==0 ) zName = pTab->zName;
1411         if( onError==OE_Replace ) onError = OE_Abort; /* IMP: R-15569-63625 */
1412         sqlite3HaltConstraint(pParse, SQLITE_CONSTRAINT_CHECK,
1413                               onError, zName, P4_TRANSIENT,
1414                               P5_ConstraintCheck);
1415       }
1416       sqlite3VdbeResolveLabel(v, allOk);
1417     }
1418     pParse->iSelfTab = 0;
1419   }
1420 #endif /* !defined(SQLITE_OMIT_CHECK) */
1421 
1422   /* UNIQUE and PRIMARY KEY constraints should be handled in the following
1423   ** order:
1424   **
1425   **   (1)  OE_Update
1426   **   (2)  OE_Abort, OE_Fail, OE_Rollback, OE_Ignore
1427   **   (3)  OE_Replace
1428   **
1429   ** OE_Fail and OE_Ignore must happen before any changes are made.
1430   ** OE_Update guarantees that only a single row will change, so it
1431   ** must happen before OE_Replace.  Technically, OE_Abort and OE_Rollback
1432   ** could happen in any order, but they are grouped up front for
1433   ** convenience.
1434   **
1435   ** 2018-08-14: Ticket https://www.sqlite.org/src/info/908f001483982c43
1436   ** The order of constraints used to have OE_Update as (2) and OE_Abort
1437   ** and so forth as (1). But apparently PostgreSQL checks the OE_Update
1438   ** constraint before any others, so it had to be moved.
1439   **
1440   ** Constraint checking code is generated in this order:
1441   **   (A)  The rowid constraint
1442   **   (B)  Unique index constraints that do not have OE_Replace as their
1443   **        default conflict resolution strategy
1444   **   (C)  Unique index that do use OE_Replace by default.
1445   **
1446   ** The ordering of (2) and (3) is accomplished by making sure the linked
1447   ** list of indexes attached to a table puts all OE_Replace indexes last
1448   ** in the list.  See sqlite3CreateIndex() for where that happens.
1449   */
1450 
1451   if( pUpsert ){
1452     if( pUpsert->pUpsertTarget==0 ){
1453       /* An ON CONFLICT DO NOTHING clause, without a constraint-target.
1454       ** Make all unique constraint resolution be OE_Ignore */
1455       assert( pUpsert->pUpsertSet==0 );
1456       overrideError = OE_Ignore;
1457       pUpsert = 0;
1458     }else if( (pUpIdx = pUpsert->pUpsertIdx)!=0 ){
1459       /* If the constraint-target uniqueness check must be run first.
1460       ** Jump to that uniqueness check now */
1461       upsertJump = sqlite3VdbeAddOp0(v, OP_Goto);
1462       VdbeComment((v, "UPSERT constraint goes first"));
1463     }
1464   }
1465 
1466   /* If rowid is changing, make sure the new rowid does not previously
1467   ** exist in the table.
1468   */
1469   if( pkChng && pPk==0 ){
1470     int addrRowidOk = sqlite3VdbeMakeLabel(v);
1471 
1472     /* Figure out what action to take in case of a rowid collision */
1473     onError = pTab->keyConf;
1474     if( overrideError!=OE_Default ){
1475       onError = overrideError;
1476     }else if( onError==OE_Default ){
1477       onError = OE_Abort;
1478     }
1479 
1480     /* figure out whether or not upsert applies in this case */
1481     if( pUpsert && pUpsert->pUpsertIdx==0 ){
1482       if( pUpsert->pUpsertSet==0 ){
1483         onError = OE_Ignore;  /* DO NOTHING is the same as INSERT OR IGNORE */
1484       }else{
1485         onError = OE_Update;  /* DO UPDATE */
1486       }
1487     }
1488 
1489     /* If the response to a rowid conflict is REPLACE but the response
1490     ** to some other UNIQUE constraint is FAIL or IGNORE, then we need
1491     ** to defer the running of the rowid conflict checking until after
1492     ** the UNIQUE constraints have run.
1493     */
1494     if( onError==OE_Replace      /* IPK rule is REPLACE */
1495      && onError!=overrideError   /* Rules for other contraints are different */
1496      && pTab->pIndex             /* There exist other constraints */
1497     ){
1498       ipkTop = sqlite3VdbeAddOp0(v, OP_Goto)+1;
1499       VdbeComment((v, "defer IPK REPLACE until last"));
1500     }
1501 
1502     if( isUpdate ){
1503       /* pkChng!=0 does not mean that the rowid has changed, only that
1504       ** it might have changed.  Skip the conflict logic below if the rowid
1505       ** is unchanged. */
1506       sqlite3VdbeAddOp3(v, OP_Eq, regNewData, addrRowidOk, regOldData);
1507       sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
1508       VdbeCoverage(v);
1509     }
1510 
1511     /* Check to see if the new rowid already exists in the table.  Skip
1512     ** the following conflict logic if it does not. */
1513     VdbeNoopComment((v, "uniqueness check for ROWID"));
1514     sqlite3VdbeVerifyAbortable(v, onError);
1515     sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, addrRowidOk, regNewData);
1516     VdbeCoverage(v);
1517 
1518     switch( onError ){
1519       default: {
1520         onError = OE_Abort;
1521         /* Fall thru into the next case */
1522       }
1523       case OE_Rollback:
1524       case OE_Abort:
1525       case OE_Fail: {
1526         testcase( onError==OE_Rollback );
1527         testcase( onError==OE_Abort );
1528         testcase( onError==OE_Fail );
1529         sqlite3RowidConstraint(pParse, onError, pTab);
1530         break;
1531       }
1532       case OE_Replace: {
1533         /* If there are DELETE triggers on this table and the
1534         ** recursive-triggers flag is set, call GenerateRowDelete() to
1535         ** remove the conflicting row from the table. This will fire
1536         ** the triggers and remove both the table and index b-tree entries.
1537         **
1538         ** Otherwise, if there are no triggers or the recursive-triggers
1539         ** flag is not set, but the table has one or more indexes, call
1540         ** GenerateRowIndexDelete(). This removes the index b-tree entries
1541         ** only. The table b-tree entry will be replaced by the new entry
1542         ** when it is inserted.
1543         **
1544         ** If either GenerateRowDelete() or GenerateRowIndexDelete() is called,
1545         ** also invoke MultiWrite() to indicate that this VDBE may require
1546         ** statement rollback (if the statement is aborted after the delete
1547         ** takes place). Earlier versions called sqlite3MultiWrite() regardless,
1548         ** but being more selective here allows statements like:
1549         **
1550         **   REPLACE INTO t(rowid) VALUES($newrowid)
1551         **
1552         ** to run without a statement journal if there are no indexes on the
1553         ** table.
1554         */
1555         Trigger *pTrigger = 0;
1556         if( db->flags&SQLITE_RecTriggers ){
1557           pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
1558         }
1559         if( pTrigger || sqlite3FkRequired(pParse, pTab, 0, 0) ){
1560           sqlite3MultiWrite(pParse);
1561           sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
1562                                    regNewData, 1, 0, OE_Replace, 1, -1);
1563         }else{
1564 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
1565           assert( HasRowid(pTab) );
1566           /* This OP_Delete opcode fires the pre-update-hook only. It does
1567           ** not modify the b-tree. It is more efficient to let the coming
1568           ** OP_Insert replace the existing entry than it is to delete the
1569           ** existing entry and then insert a new one. */
1570           sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, OPFLAG_ISNOOP);
1571           sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
1572 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
1573           if( pTab->pIndex ){
1574             sqlite3MultiWrite(pParse);
1575             sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur,0,-1);
1576           }
1577         }
1578         seenReplace = 1;
1579         break;
1580       }
1581 #ifndef SQLITE_OMIT_UPSERT
1582       case OE_Update: {
1583         sqlite3UpsertDoUpdate(pParse, pUpsert, pTab, 0, iDataCur);
1584         /* Fall through */
1585       }
1586 #endif
1587       case OE_Ignore: {
1588         testcase( onError==OE_Ignore );
1589         sqlite3VdbeGoto(v, ignoreDest);
1590         break;
1591       }
1592     }
1593     sqlite3VdbeResolveLabel(v, addrRowidOk);
1594     if( ipkTop ){
1595       ipkBottom = sqlite3VdbeAddOp0(v, OP_Goto);
1596       sqlite3VdbeJumpHere(v, ipkTop-1);
1597     }
1598   }
1599 
1600   /* Test all UNIQUE constraints by creating entries for each UNIQUE
1601   ** index and making sure that duplicate entries do not already exist.
1602   ** Compute the revised record entries for indices as we go.
1603   **
1604   ** This loop also handles the case of the PRIMARY KEY index for a
1605   ** WITHOUT ROWID table.
1606   */
1607   for(ix=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, ix++){
1608     int regIdx;          /* Range of registers hold conent for pIdx */
1609     int regR;            /* Range of registers holding conflicting PK */
1610     int iThisCur;        /* Cursor for this UNIQUE index */
1611     int addrUniqueOk;    /* Jump here if the UNIQUE constraint is satisfied */
1612 
1613     if( aRegIdx[ix]==0 ) continue;  /* Skip indices that do not change */
1614     if( pUpIdx==pIdx ){
1615       addrUniqueOk = upsertJump+1;
1616       upsertBypass = sqlite3VdbeGoto(v, 0);
1617       VdbeComment((v, "Skip upsert subroutine"));
1618       sqlite3VdbeJumpHere(v, upsertJump);
1619     }else{
1620       addrUniqueOk = sqlite3VdbeMakeLabel(v);
1621     }
1622     if( bAffinityDone==0 && (pUpIdx==0 || pUpIdx==pIdx) ){
1623       sqlite3TableAffinity(v, pTab, regNewData+1);
1624       bAffinityDone = 1;
1625     }
1626     VdbeNoopComment((v, "uniqueness check for %s", pIdx->zName));
1627     iThisCur = iIdxCur+ix;
1628 
1629 
1630     /* Skip partial indices for which the WHERE clause is not true */
1631     if( pIdx->pPartIdxWhere ){
1632       sqlite3VdbeAddOp2(v, OP_Null, 0, aRegIdx[ix]);
1633       pParse->iSelfTab = -(regNewData+1);
1634       sqlite3ExprIfFalseDup(pParse, pIdx->pPartIdxWhere, addrUniqueOk,
1635                             SQLITE_JUMPIFNULL);
1636       pParse->iSelfTab = 0;
1637     }
1638 
1639     /* Create a record for this index entry as it should appear after
1640     ** the insert or update.  Store that record in the aRegIdx[ix] register
1641     */
1642     regIdx = aRegIdx[ix]+1;
1643     for(i=0; i<pIdx->nColumn; i++){
1644       int iField = pIdx->aiColumn[i];
1645       int x;
1646       if( iField==XN_EXPR ){
1647         pParse->iSelfTab = -(regNewData+1);
1648         sqlite3ExprCodeCopy(pParse, pIdx->aColExpr->a[i].pExpr, regIdx+i);
1649         pParse->iSelfTab = 0;
1650         VdbeComment((v, "%s column %d", pIdx->zName, i));
1651       }else{
1652         if( iField==XN_ROWID || iField==pTab->iPKey ){
1653           x = regNewData;
1654         }else{
1655           x = iField + regNewData + 1;
1656         }
1657         sqlite3VdbeAddOp2(v, iField<0 ? OP_IntCopy : OP_SCopy, x, regIdx+i);
1658         VdbeComment((v, "%s", iField<0 ? "rowid" : pTab->aCol[iField].zName));
1659       }
1660     }
1661     sqlite3VdbeAddOp3(v, OP_MakeRecord, regIdx, pIdx->nColumn, aRegIdx[ix]);
1662     VdbeComment((v, "for %s", pIdx->zName));
1663 #ifdef SQLITE_ENABLE_NULL_TRIM
1664     if( pIdx->idxType==2 ) sqlite3SetMakeRecordP5(v, pIdx->pTable);
1665 #endif
1666 
1667     /* In an UPDATE operation, if this index is the PRIMARY KEY index
1668     ** of a WITHOUT ROWID table and there has been no change the
1669     ** primary key, then no collision is possible.  The collision detection
1670     ** logic below can all be skipped. */
1671     if( isUpdate && pPk==pIdx && pkChng==0 ){
1672       sqlite3VdbeResolveLabel(v, addrUniqueOk);
1673       continue;
1674     }
1675 
1676     /* Find out what action to take in case there is a uniqueness conflict */
1677     onError = pIdx->onError;
1678     if( onError==OE_None ){
1679       sqlite3VdbeResolveLabel(v, addrUniqueOk);
1680       continue;  /* pIdx is not a UNIQUE index */
1681     }
1682     if( overrideError!=OE_Default ){
1683       onError = overrideError;
1684     }else if( onError==OE_Default ){
1685       onError = OE_Abort;
1686     }
1687 
1688     /* Figure out if the upsert clause applies to this index */
1689     if( pUpIdx==pIdx ){
1690       if( pUpsert->pUpsertSet==0 ){
1691         onError = OE_Ignore;  /* DO NOTHING is the same as INSERT OR IGNORE */
1692       }else{
1693         onError = OE_Update;  /* DO UPDATE */
1694       }
1695     }
1696 
1697     /* Collision detection may be omitted if all of the following are true:
1698     **   (1) The conflict resolution algorithm is REPLACE
1699     **   (2) The table is a WITHOUT ROWID table
1700     **   (3) There are no secondary indexes on the table
1701     **   (4) No delete triggers need to be fired if there is a conflict
1702     **   (5) No FK constraint counters need to be updated if a conflict occurs.
1703     */
1704     if( (ix==0 && pIdx->pNext==0)                   /* Condition 3 */
1705      && pPk==pIdx                                   /* Condition 2 */
1706      && onError==OE_Replace                         /* Condition 1 */
1707      && ( 0==(db->flags&SQLITE_RecTriggers) ||      /* Condition 4 */
1708           0==sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0))
1709      && ( 0==(db->flags&SQLITE_ForeignKeys) ||      /* Condition 5 */
1710          (0==pTab->pFKey && 0==sqlite3FkReferences(pTab)))
1711     ){
1712       sqlite3VdbeResolveLabel(v, addrUniqueOk);
1713       continue;
1714     }
1715 
1716     /* Check to see if the new index entry will be unique */
1717     sqlite3VdbeVerifyAbortable(v, onError);
1718     sqlite3VdbeAddOp4Int(v, OP_NoConflict, iThisCur, addrUniqueOk,
1719                          regIdx, pIdx->nKeyCol); VdbeCoverage(v);
1720 
1721     /* Generate code to handle collisions */
1722     regR = (pIdx==pPk) ? regIdx : sqlite3GetTempRange(pParse, nPkField);
1723     if( isUpdate || onError==OE_Replace ){
1724       if( HasRowid(pTab) ){
1725         sqlite3VdbeAddOp2(v, OP_IdxRowid, iThisCur, regR);
1726         /* Conflict only if the rowid of the existing index entry
1727         ** is different from old-rowid */
1728         if( isUpdate ){
1729           sqlite3VdbeAddOp3(v, OP_Eq, regR, addrUniqueOk, regOldData);
1730           sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
1731           VdbeCoverage(v);
1732         }
1733       }else{
1734         int x;
1735         /* Extract the PRIMARY KEY from the end of the index entry and
1736         ** store it in registers regR..regR+nPk-1 */
1737         if( pIdx!=pPk ){
1738           for(i=0; i<pPk->nKeyCol; i++){
1739             assert( pPk->aiColumn[i]>=0 );
1740             x = sqlite3ColumnOfIndex(pIdx, pPk->aiColumn[i]);
1741             sqlite3VdbeAddOp3(v, OP_Column, iThisCur, x, regR+i);
1742             VdbeComment((v, "%s.%s", pTab->zName,
1743                          pTab->aCol[pPk->aiColumn[i]].zName));
1744           }
1745         }
1746         if( isUpdate ){
1747           /* If currently processing the PRIMARY KEY of a WITHOUT ROWID
1748           ** table, only conflict if the new PRIMARY KEY values are actually
1749           ** different from the old.
1750           **
1751           ** For a UNIQUE index, only conflict if the PRIMARY KEY values
1752           ** of the matched index row are different from the original PRIMARY
1753           ** KEY values of this row before the update.  */
1754           int addrJump = sqlite3VdbeCurrentAddr(v)+pPk->nKeyCol;
1755           int op = OP_Ne;
1756           int regCmp = (IsPrimaryKeyIndex(pIdx) ? regIdx : regR);
1757 
1758           for(i=0; i<pPk->nKeyCol; i++){
1759             char *p4 = (char*)sqlite3LocateCollSeq(pParse, pPk->azColl[i]);
1760             x = pPk->aiColumn[i];
1761             assert( x>=0 );
1762             if( i==(pPk->nKeyCol-1) ){
1763               addrJump = addrUniqueOk;
1764               op = OP_Eq;
1765             }
1766             sqlite3VdbeAddOp4(v, op,
1767                 regOldData+1+x, addrJump, regCmp+i, p4, P4_COLLSEQ
1768             );
1769             sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
1770             VdbeCoverageIf(v, op==OP_Eq);
1771             VdbeCoverageIf(v, op==OP_Ne);
1772           }
1773         }
1774       }
1775     }
1776 
1777     /* Generate code that executes if the new index entry is not unique */
1778     assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
1779         || onError==OE_Ignore || onError==OE_Replace || onError==OE_Update );
1780     switch( onError ){
1781       case OE_Rollback:
1782       case OE_Abort:
1783       case OE_Fail: {
1784         testcase( onError==OE_Rollback );
1785         testcase( onError==OE_Abort );
1786         testcase( onError==OE_Fail );
1787         sqlite3UniqueConstraint(pParse, onError, pIdx);
1788         break;
1789       }
1790 #ifndef SQLITE_OMIT_UPSERT
1791       case OE_Update: {
1792         sqlite3UpsertDoUpdate(pParse, pUpsert, pTab, pIdx, iIdxCur+ix);
1793         /* Fall through */
1794       }
1795 #endif
1796       case OE_Ignore: {
1797         testcase( onError==OE_Ignore );
1798         sqlite3VdbeGoto(v, ignoreDest);
1799         break;
1800       }
1801       default: {
1802         Trigger *pTrigger = 0;
1803         assert( onError==OE_Replace );
1804         if( db->flags&SQLITE_RecTriggers ){
1805           pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
1806         }
1807         if( pTrigger || sqlite3FkRequired(pParse, pTab, 0, 0) ){
1808           sqlite3MultiWrite(pParse);
1809         }
1810         sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
1811             regR, nPkField, 0, OE_Replace,
1812             (pIdx==pPk ? ONEPASS_SINGLE : ONEPASS_OFF), iThisCur);
1813         seenReplace = 1;
1814         break;
1815       }
1816     }
1817     if( pUpIdx==pIdx ){
1818       sqlite3VdbeGoto(v, upsertJump+1);
1819       sqlite3VdbeJumpHere(v, upsertBypass);
1820     }else{
1821       sqlite3VdbeResolveLabel(v, addrUniqueOk);
1822     }
1823     if( regR!=regIdx ) sqlite3ReleaseTempRange(pParse, regR, nPkField);
1824   }
1825 
1826   /* If the IPK constraint is a REPLACE, run it last */
1827   if( ipkTop ){
1828     sqlite3VdbeGoto(v, ipkTop+1);
1829     VdbeComment((v, "Do IPK REPLACE"));
1830     sqlite3VdbeJumpHere(v, ipkBottom);
1831   }
1832 
1833   *pbMayReplace = seenReplace;
1834   VdbeModuleComment((v, "END: GenCnstCks(%d)", seenReplace));
1835 }
1836 
1837 #ifdef SQLITE_ENABLE_NULL_TRIM
1838 /*
1839 ** Change the P5 operand on the last opcode (which should be an OP_MakeRecord)
1840 ** to be the number of columns in table pTab that must not be NULL-trimmed.
1841 **
1842 ** Or if no columns of pTab may be NULL-trimmed, leave P5 at zero.
1843 */
1844 void sqlite3SetMakeRecordP5(Vdbe *v, Table *pTab){
1845   u16 i;
1846 
1847   /* Records with omitted columns are only allowed for schema format
1848   ** version 2 and later (SQLite version 3.1.4, 2005-02-20). */
1849   if( pTab->pSchema->file_format<2 ) return;
1850 
1851   for(i=pTab->nCol-1; i>0; i--){
1852     if( pTab->aCol[i].pDflt!=0 ) break;
1853     if( pTab->aCol[i].colFlags & COLFLAG_PRIMKEY ) break;
1854   }
1855   sqlite3VdbeChangeP5(v, i+1);
1856 }
1857 #endif
1858 
1859 /*
1860 ** This routine generates code to finish the INSERT or UPDATE operation
1861 ** that was started by a prior call to sqlite3GenerateConstraintChecks.
1862 ** A consecutive range of registers starting at regNewData contains the
1863 ** rowid and the content to be inserted.
1864 **
1865 ** The arguments to this routine should be the same as the first six
1866 ** arguments to sqlite3GenerateConstraintChecks.
1867 */
1868 void sqlite3CompleteInsertion(
1869   Parse *pParse,      /* The parser context */
1870   Table *pTab,        /* the table into which we are inserting */
1871   int iDataCur,       /* Cursor of the canonical data source */
1872   int iIdxCur,        /* First index cursor */
1873   int regNewData,     /* Range of content */
1874   int *aRegIdx,       /* Register used by each index.  0 for unused indices */
1875   int update_flags,   /* True for UPDATE, False for INSERT */
1876   int appendBias,     /* True if this is likely to be an append */
1877   int useSeekResult   /* True to set the USESEEKRESULT flag on OP_[Idx]Insert */
1878 ){
1879   Vdbe *v;            /* Prepared statements under construction */
1880   Index *pIdx;        /* An index being inserted or updated */
1881   u8 pik_flags;       /* flag values passed to the btree insert */
1882   int regData;        /* Content registers (after the rowid) */
1883   int regRec;         /* Register holding assembled record for the table */
1884   int i;              /* Loop counter */
1885   u8 bAffinityDone = 0; /* True if OP_Affinity has been run already */
1886 
1887   assert( update_flags==0
1888        || update_flags==OPFLAG_ISUPDATE
1889        || update_flags==(OPFLAG_ISUPDATE|OPFLAG_SAVEPOSITION)
1890   );
1891 
1892   v = sqlite3GetVdbe(pParse);
1893   assert( v!=0 );
1894   assert( pTab->pSelect==0 );  /* This table is not a VIEW */
1895   for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
1896     if( aRegIdx[i]==0 ) continue;
1897     bAffinityDone = 1;
1898     if( pIdx->pPartIdxWhere ){
1899       sqlite3VdbeAddOp2(v, OP_IsNull, aRegIdx[i], sqlite3VdbeCurrentAddr(v)+2);
1900       VdbeCoverage(v);
1901     }
1902     pik_flags = (useSeekResult ? OPFLAG_USESEEKRESULT : 0);
1903     if( IsPrimaryKeyIndex(pIdx) && !HasRowid(pTab) ){
1904       assert( pParse->nested==0 );
1905       pik_flags |= OPFLAG_NCHANGE;
1906       pik_flags |= (update_flags & OPFLAG_SAVEPOSITION);
1907 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
1908       if( update_flags==0 ){
1909         sqlite3VdbeAddOp4(v, OP_InsertInt,
1910             iIdxCur+i, aRegIdx[i], 0, (char*)pTab, P4_TABLE
1911         );
1912         sqlite3VdbeChangeP5(v, OPFLAG_ISNOOP);
1913       }
1914 #endif
1915     }
1916     sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iIdxCur+i, aRegIdx[i],
1917                          aRegIdx[i]+1,
1918                          pIdx->uniqNotNull ? pIdx->nKeyCol: pIdx->nColumn);
1919     sqlite3VdbeChangeP5(v, pik_flags);
1920   }
1921   if( !HasRowid(pTab) ) return;
1922   regData = regNewData + 1;
1923   regRec = sqlite3GetTempReg(pParse);
1924   sqlite3VdbeAddOp3(v, OP_MakeRecord, regData, pTab->nCol, regRec);
1925   sqlite3SetMakeRecordP5(v, pTab);
1926   if( !bAffinityDone ){
1927     sqlite3TableAffinity(v, pTab, 0);
1928   }
1929   if( pParse->nested ){
1930     pik_flags = 0;
1931   }else{
1932     pik_flags = OPFLAG_NCHANGE;
1933     pik_flags |= (update_flags?update_flags:OPFLAG_LASTROWID);
1934   }
1935   if( appendBias ){
1936     pik_flags |= OPFLAG_APPEND;
1937   }
1938   if( useSeekResult ){
1939     pik_flags |= OPFLAG_USESEEKRESULT;
1940   }
1941   sqlite3VdbeAddOp3(v, OP_Insert, iDataCur, regRec, regNewData);
1942   if( !pParse->nested ){
1943     sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
1944   }
1945   sqlite3VdbeChangeP5(v, pik_flags);
1946 }
1947 
1948 /*
1949 ** Allocate cursors for the pTab table and all its indices and generate
1950 ** code to open and initialized those cursors.
1951 **
1952 ** The cursor for the object that contains the complete data (normally
1953 ** the table itself, but the PRIMARY KEY index in the case of a WITHOUT
1954 ** ROWID table) is returned in *piDataCur.  The first index cursor is
1955 ** returned in *piIdxCur.  The number of indices is returned.
1956 **
1957 ** Use iBase as the first cursor (either the *piDataCur for rowid tables
1958 ** or the first index for WITHOUT ROWID tables) if it is non-negative.
1959 ** If iBase is negative, then allocate the next available cursor.
1960 **
1961 ** For a rowid table, *piDataCur will be exactly one less than *piIdxCur.
1962 ** For a WITHOUT ROWID table, *piDataCur will be somewhere in the range
1963 ** of *piIdxCurs, depending on where the PRIMARY KEY index appears on the
1964 ** pTab->pIndex list.
1965 **
1966 ** If pTab is a virtual table, then this routine is a no-op and the
1967 ** *piDataCur and *piIdxCur values are left uninitialized.
1968 */
1969 int sqlite3OpenTableAndIndices(
1970   Parse *pParse,   /* Parsing context */
1971   Table *pTab,     /* Table to be opened */
1972   int op,          /* OP_OpenRead or OP_OpenWrite */
1973   u8 p5,           /* P5 value for OP_Open* opcodes (except on WITHOUT ROWID) */
1974   int iBase,       /* Use this for the table cursor, if there is one */
1975   u8 *aToOpen,     /* If not NULL: boolean for each table and index */
1976   int *piDataCur,  /* Write the database source cursor number here */
1977   int *piIdxCur    /* Write the first index cursor number here */
1978 ){
1979   int i;
1980   int iDb;
1981   int iDataCur;
1982   Index *pIdx;
1983   Vdbe *v;
1984 
1985   assert( op==OP_OpenRead || op==OP_OpenWrite );
1986   assert( op==OP_OpenWrite || p5==0 );
1987   if( IsVirtual(pTab) ){
1988     /* This routine is a no-op for virtual tables. Leave the output
1989     ** variables *piDataCur and *piIdxCur uninitialized so that valgrind
1990     ** can detect if they are used by mistake in the caller. */
1991     return 0;
1992   }
1993   iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
1994   v = sqlite3GetVdbe(pParse);
1995   assert( v!=0 );
1996   if( iBase<0 ) iBase = pParse->nTab;
1997   iDataCur = iBase++;
1998   if( piDataCur ) *piDataCur = iDataCur;
1999   if( HasRowid(pTab) && (aToOpen==0 || aToOpen[0]) ){
2000     sqlite3OpenTable(pParse, iDataCur, iDb, pTab, op);
2001   }else{
2002     sqlite3TableLock(pParse, iDb, pTab->tnum, op==OP_OpenWrite, pTab->zName);
2003   }
2004   if( piIdxCur ) *piIdxCur = iBase;
2005   for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
2006     int iIdxCur = iBase++;
2007     assert( pIdx->pSchema==pTab->pSchema );
2008     if( IsPrimaryKeyIndex(pIdx) && !HasRowid(pTab) ){
2009       if( piDataCur ) *piDataCur = iIdxCur;
2010       p5 = 0;
2011     }
2012     if( aToOpen==0 || aToOpen[i+1] ){
2013       sqlite3VdbeAddOp3(v, op, iIdxCur, pIdx->tnum, iDb);
2014       sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
2015       sqlite3VdbeChangeP5(v, p5);
2016       VdbeComment((v, "%s", pIdx->zName));
2017     }
2018   }
2019   if( iBase>pParse->nTab ) pParse->nTab = iBase;
2020   return i;
2021 }
2022 
2023 
2024 #ifdef SQLITE_TEST
2025 /*
2026 ** The following global variable is incremented whenever the
2027 ** transfer optimization is used.  This is used for testing
2028 ** purposes only - to make sure the transfer optimization really
2029 ** is happening when it is supposed to.
2030 */
2031 int sqlite3_xferopt_count;
2032 #endif /* SQLITE_TEST */
2033 
2034 
2035 #ifndef SQLITE_OMIT_XFER_OPT
2036 /*
2037 ** Check to see if index pSrc is compatible as a source of data
2038 ** for index pDest in an insert transfer optimization.  The rules
2039 ** for a compatible index:
2040 **
2041 **    *   The index is over the same set of columns
2042 **    *   The same DESC and ASC markings occurs on all columns
2043 **    *   The same onError processing (OE_Abort, OE_Ignore, etc)
2044 **    *   The same collating sequence on each column
2045 **    *   The index has the exact same WHERE clause
2046 */
2047 static int xferCompatibleIndex(Index *pDest, Index *pSrc){
2048   int i;
2049   assert( pDest && pSrc );
2050   assert( pDest->pTable!=pSrc->pTable );
2051   if( pDest->nKeyCol!=pSrc->nKeyCol ){
2052     return 0;   /* Different number of columns */
2053   }
2054   if( pDest->onError!=pSrc->onError ){
2055     return 0;   /* Different conflict resolution strategies */
2056   }
2057   for(i=0; i<pSrc->nKeyCol; i++){
2058     if( pSrc->aiColumn[i]!=pDest->aiColumn[i] ){
2059       return 0;   /* Different columns indexed */
2060     }
2061     if( pSrc->aiColumn[i]==XN_EXPR ){
2062       assert( pSrc->aColExpr!=0 && pDest->aColExpr!=0 );
2063       if( sqlite3ExprCompare(0, pSrc->aColExpr->a[i].pExpr,
2064                              pDest->aColExpr->a[i].pExpr, -1)!=0 ){
2065         return 0;   /* Different expressions in the index */
2066       }
2067     }
2068     if( pSrc->aSortOrder[i]!=pDest->aSortOrder[i] ){
2069       return 0;   /* Different sort orders */
2070     }
2071     if( sqlite3_stricmp(pSrc->azColl[i],pDest->azColl[i])!=0 ){
2072       return 0;   /* Different collating sequences */
2073     }
2074   }
2075   if( sqlite3ExprCompare(0, pSrc->pPartIdxWhere, pDest->pPartIdxWhere, -1) ){
2076     return 0;     /* Different WHERE clauses */
2077   }
2078 
2079   /* If no test above fails then the indices must be compatible */
2080   return 1;
2081 }
2082 
2083 /*
2084 ** Attempt the transfer optimization on INSERTs of the form
2085 **
2086 **     INSERT INTO tab1 SELECT * FROM tab2;
2087 **
2088 ** The xfer optimization transfers raw records from tab2 over to tab1.
2089 ** Columns are not decoded and reassembled, which greatly improves
2090 ** performance.  Raw index records are transferred in the same way.
2091 **
2092 ** The xfer optimization is only attempted if tab1 and tab2 are compatible.
2093 ** There are lots of rules for determining compatibility - see comments
2094 ** embedded in the code for details.
2095 **
2096 ** This routine returns TRUE if the optimization is guaranteed to be used.
2097 ** Sometimes the xfer optimization will only work if the destination table
2098 ** is empty - a factor that can only be determined at run-time.  In that
2099 ** case, this routine generates code for the xfer optimization but also
2100 ** does a test to see if the destination table is empty and jumps over the
2101 ** xfer optimization code if the test fails.  In that case, this routine
2102 ** returns FALSE so that the caller will know to go ahead and generate
2103 ** an unoptimized transfer.  This routine also returns FALSE if there
2104 ** is no chance that the xfer optimization can be applied.
2105 **
2106 ** This optimization is particularly useful at making VACUUM run faster.
2107 */
2108 static int xferOptimization(
2109   Parse *pParse,        /* Parser context */
2110   Table *pDest,         /* The table we are inserting into */
2111   Select *pSelect,      /* A SELECT statement to use as the data source */
2112   int onError,          /* How to handle constraint errors */
2113   int iDbDest           /* The database of pDest */
2114 ){
2115   sqlite3 *db = pParse->db;
2116   ExprList *pEList;                /* The result set of the SELECT */
2117   Table *pSrc;                     /* The table in the FROM clause of SELECT */
2118   Index *pSrcIdx, *pDestIdx;       /* Source and destination indices */
2119   struct SrcList_item *pItem;      /* An element of pSelect->pSrc */
2120   int i;                           /* Loop counter */
2121   int iDbSrc;                      /* The database of pSrc */
2122   int iSrc, iDest;                 /* Cursors from source and destination */
2123   int addr1, addr2;                /* Loop addresses */
2124   int emptyDestTest = 0;           /* Address of test for empty pDest */
2125   int emptySrcTest = 0;            /* Address of test for empty pSrc */
2126   Vdbe *v;                         /* The VDBE we are building */
2127   int regAutoinc;                  /* Memory register used by AUTOINC */
2128   int destHasUniqueIdx = 0;        /* True if pDest has a UNIQUE index */
2129   int regData, regRowid;           /* Registers holding data and rowid */
2130 
2131   if( pSelect==0 ){
2132     return 0;   /* Must be of the form  INSERT INTO ... SELECT ... */
2133   }
2134   if( pParse->pWith || pSelect->pWith ){
2135     /* Do not attempt to process this query if there are an WITH clauses
2136     ** attached to it. Proceeding may generate a false "no such table: xxx"
2137     ** error if pSelect reads from a CTE named "xxx".  */
2138     return 0;
2139   }
2140   if( sqlite3TriggerList(pParse, pDest) ){
2141     return 0;   /* tab1 must not have triggers */
2142   }
2143 #ifndef SQLITE_OMIT_VIRTUALTABLE
2144   if( IsVirtual(pDest) ){
2145     return 0;   /* tab1 must not be a virtual table */
2146   }
2147 #endif
2148   if( onError==OE_Default ){
2149     if( pDest->iPKey>=0 ) onError = pDest->keyConf;
2150     if( onError==OE_Default ) onError = OE_Abort;
2151   }
2152   assert(pSelect->pSrc);   /* allocated even if there is no FROM clause */
2153   if( pSelect->pSrc->nSrc!=1 ){
2154     return 0;   /* FROM clause must have exactly one term */
2155   }
2156   if( pSelect->pSrc->a[0].pSelect ){
2157     return 0;   /* FROM clause cannot contain a subquery */
2158   }
2159   if( pSelect->pWhere ){
2160     return 0;   /* SELECT may not have a WHERE clause */
2161   }
2162   if( pSelect->pOrderBy ){
2163     return 0;   /* SELECT may not have an ORDER BY clause */
2164   }
2165   /* Do not need to test for a HAVING clause.  If HAVING is present but
2166   ** there is no ORDER BY, we will get an error. */
2167   if( pSelect->pGroupBy ){
2168     return 0;   /* SELECT may not have a GROUP BY clause */
2169   }
2170   if( pSelect->pLimit ){
2171     return 0;   /* SELECT may not have a LIMIT clause */
2172   }
2173   if( pSelect->pPrior ){
2174     return 0;   /* SELECT may not be a compound query */
2175   }
2176   if( pSelect->selFlags & SF_Distinct ){
2177     return 0;   /* SELECT may not be DISTINCT */
2178   }
2179   pEList = pSelect->pEList;
2180   assert( pEList!=0 );
2181   if( pEList->nExpr!=1 ){
2182     return 0;   /* The result set must have exactly one column */
2183   }
2184   assert( pEList->a[0].pExpr );
2185   if( pEList->a[0].pExpr->op!=TK_ASTERISK ){
2186     return 0;   /* The result set must be the special operator "*" */
2187   }
2188 
2189   /* At this point we have established that the statement is of the
2190   ** correct syntactic form to participate in this optimization.  Now
2191   ** we have to check the semantics.
2192   */
2193   pItem = pSelect->pSrc->a;
2194   pSrc = sqlite3LocateTableItem(pParse, 0, pItem);
2195   if( pSrc==0 ){
2196     return 0;   /* FROM clause does not contain a real table */
2197   }
2198   if( pSrc==pDest ){
2199     return 0;   /* tab1 and tab2 may not be the same table */
2200   }
2201   if( HasRowid(pDest)!=HasRowid(pSrc) ){
2202     return 0;   /* source and destination must both be WITHOUT ROWID or not */
2203   }
2204 #ifndef SQLITE_OMIT_VIRTUALTABLE
2205   if( IsVirtual(pSrc) ){
2206     return 0;   /* tab2 must not be a virtual table */
2207   }
2208 #endif
2209   if( pSrc->pSelect ){
2210     return 0;   /* tab2 may not be a view */
2211   }
2212   if( pDest->nCol!=pSrc->nCol ){
2213     return 0;   /* Number of columns must be the same in tab1 and tab2 */
2214   }
2215   if( pDest->iPKey!=pSrc->iPKey ){
2216     return 0;   /* Both tables must have the same INTEGER PRIMARY KEY */
2217   }
2218   for(i=0; i<pDest->nCol; i++){
2219     Column *pDestCol = &pDest->aCol[i];
2220     Column *pSrcCol = &pSrc->aCol[i];
2221 #ifdef SQLITE_ENABLE_HIDDEN_COLUMNS
2222     if( (db->mDbFlags & DBFLAG_Vacuum)==0
2223      && (pDestCol->colFlags | pSrcCol->colFlags) & COLFLAG_HIDDEN
2224     ){
2225       return 0;    /* Neither table may have __hidden__ columns */
2226     }
2227 #endif
2228     if( pDestCol->affinity!=pSrcCol->affinity ){
2229       return 0;    /* Affinity must be the same on all columns */
2230     }
2231     if( sqlite3_stricmp(pDestCol->zColl, pSrcCol->zColl)!=0 ){
2232       return 0;    /* Collating sequence must be the same on all columns */
2233     }
2234     if( pDestCol->notNull && !pSrcCol->notNull ){
2235       return 0;    /* tab2 must be NOT NULL if tab1 is */
2236     }
2237     /* Default values for second and subsequent columns need to match. */
2238     if( i>0 ){
2239       assert( pDestCol->pDflt==0 || pDestCol->pDflt->op==TK_SPAN );
2240       assert( pSrcCol->pDflt==0 || pSrcCol->pDflt->op==TK_SPAN );
2241       if( (pDestCol->pDflt==0)!=(pSrcCol->pDflt==0)
2242        || (pDestCol->pDflt && strcmp(pDestCol->pDflt->u.zToken,
2243                                        pSrcCol->pDflt->u.zToken)!=0)
2244       ){
2245         return 0;    /* Default values must be the same for all columns */
2246       }
2247     }
2248   }
2249   for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
2250     if( IsUniqueIndex(pDestIdx) ){
2251       destHasUniqueIdx = 1;
2252     }
2253     for(pSrcIdx=pSrc->pIndex; pSrcIdx; pSrcIdx=pSrcIdx->pNext){
2254       if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
2255     }
2256     if( pSrcIdx==0 ){
2257       return 0;    /* pDestIdx has no corresponding index in pSrc */
2258     }
2259   }
2260 #ifndef SQLITE_OMIT_CHECK
2261   if( pDest->pCheck && sqlite3ExprListCompare(pSrc->pCheck,pDest->pCheck,-1) ){
2262     return 0;   /* Tables have different CHECK constraints.  Ticket #2252 */
2263   }
2264 #endif
2265 #ifndef SQLITE_OMIT_FOREIGN_KEY
2266   /* Disallow the transfer optimization if the destination table constains
2267   ** any foreign key constraints.  This is more restrictive than necessary.
2268   ** But the main beneficiary of the transfer optimization is the VACUUM
2269   ** command, and the VACUUM command disables foreign key constraints.  So
2270   ** the extra complication to make this rule less restrictive is probably
2271   ** not worth the effort.  Ticket [6284df89debdfa61db8073e062908af0c9b6118e]
2272   */
2273   if( (db->flags & SQLITE_ForeignKeys)!=0 && pDest->pFKey!=0 ){
2274     return 0;
2275   }
2276 #endif
2277   if( (db->flags & SQLITE_CountRows)!=0 ){
2278     return 0;  /* xfer opt does not play well with PRAGMA count_changes */
2279   }
2280 
2281   /* If we get this far, it means that the xfer optimization is at
2282   ** least a possibility, though it might only work if the destination
2283   ** table (tab1) is initially empty.
2284   */
2285 #ifdef SQLITE_TEST
2286   sqlite3_xferopt_count++;
2287 #endif
2288   iDbSrc = sqlite3SchemaToIndex(db, pSrc->pSchema);
2289   v = sqlite3GetVdbe(pParse);
2290   sqlite3CodeVerifySchema(pParse, iDbSrc);
2291   iSrc = pParse->nTab++;
2292   iDest = pParse->nTab++;
2293   regAutoinc = autoIncBegin(pParse, iDbDest, pDest);
2294   regData = sqlite3GetTempReg(pParse);
2295   regRowid = sqlite3GetTempReg(pParse);
2296   sqlite3OpenTable(pParse, iDest, iDbDest, pDest, OP_OpenWrite);
2297   assert( HasRowid(pDest) || destHasUniqueIdx );
2298   if( (db->mDbFlags & DBFLAG_Vacuum)==0 && (
2299       (pDest->iPKey<0 && pDest->pIndex!=0)          /* (1) */
2300    || destHasUniqueIdx                              /* (2) */
2301    || (onError!=OE_Abort && onError!=OE_Rollback)   /* (3) */
2302   )){
2303     /* In some circumstances, we are able to run the xfer optimization
2304     ** only if the destination table is initially empty. Unless the
2305     ** DBFLAG_Vacuum flag is set, this block generates code to make
2306     ** that determination. If DBFLAG_Vacuum is set, then the destination
2307     ** table is always empty.
2308     **
2309     ** Conditions under which the destination must be empty:
2310     **
2311     ** (1) There is no INTEGER PRIMARY KEY but there are indices.
2312     **     (If the destination is not initially empty, the rowid fields
2313     **     of index entries might need to change.)
2314     **
2315     ** (2) The destination has a unique index.  (The xfer optimization
2316     **     is unable to test uniqueness.)
2317     **
2318     ** (3) onError is something other than OE_Abort and OE_Rollback.
2319     */
2320     addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iDest, 0); VdbeCoverage(v);
2321     emptyDestTest = sqlite3VdbeAddOp0(v, OP_Goto);
2322     sqlite3VdbeJumpHere(v, addr1);
2323   }
2324   if( HasRowid(pSrc) ){
2325     u8 insFlags;
2326     sqlite3OpenTable(pParse, iSrc, iDbSrc, pSrc, OP_OpenRead);
2327     emptySrcTest = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0); VdbeCoverage(v);
2328     if( pDest->iPKey>=0 ){
2329       addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
2330       sqlite3VdbeVerifyAbortable(v, onError);
2331       addr2 = sqlite3VdbeAddOp3(v, OP_NotExists, iDest, 0, regRowid);
2332       VdbeCoverage(v);
2333       sqlite3RowidConstraint(pParse, onError, pDest);
2334       sqlite3VdbeJumpHere(v, addr2);
2335       autoIncStep(pParse, regAutoinc, regRowid);
2336     }else if( pDest->pIndex==0 ){
2337       addr1 = sqlite3VdbeAddOp2(v, OP_NewRowid, iDest, regRowid);
2338     }else{
2339       addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
2340       assert( (pDest->tabFlags & TF_Autoincrement)==0 );
2341     }
2342     sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
2343     if( db->mDbFlags & DBFLAG_Vacuum ){
2344       sqlite3VdbeAddOp1(v, OP_SeekEnd, iDest);
2345       insFlags = OPFLAG_NCHANGE|OPFLAG_LASTROWID|
2346                            OPFLAG_APPEND|OPFLAG_USESEEKRESULT;
2347     }else{
2348       insFlags = OPFLAG_NCHANGE|OPFLAG_LASTROWID|OPFLAG_APPEND;
2349     }
2350     sqlite3VdbeAddOp4(v, OP_Insert, iDest, regData, regRowid,
2351                       (char*)pDest, P4_TABLE);
2352     sqlite3VdbeChangeP5(v, insFlags);
2353     sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1); VdbeCoverage(v);
2354     sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
2355     sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
2356   }else{
2357     sqlite3TableLock(pParse, iDbDest, pDest->tnum, 1, pDest->zName);
2358     sqlite3TableLock(pParse, iDbSrc, pSrc->tnum, 0, pSrc->zName);
2359   }
2360   for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
2361     u8 idxInsFlags = 0;
2362     for(pSrcIdx=pSrc->pIndex; ALWAYS(pSrcIdx); pSrcIdx=pSrcIdx->pNext){
2363       if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
2364     }
2365     assert( pSrcIdx );
2366     sqlite3VdbeAddOp3(v, OP_OpenRead, iSrc, pSrcIdx->tnum, iDbSrc);
2367     sqlite3VdbeSetP4KeyInfo(pParse, pSrcIdx);
2368     VdbeComment((v, "%s", pSrcIdx->zName));
2369     sqlite3VdbeAddOp3(v, OP_OpenWrite, iDest, pDestIdx->tnum, iDbDest);
2370     sqlite3VdbeSetP4KeyInfo(pParse, pDestIdx);
2371     sqlite3VdbeChangeP5(v, OPFLAG_BULKCSR);
2372     VdbeComment((v, "%s", pDestIdx->zName));
2373     addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0); VdbeCoverage(v);
2374     sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
2375     if( db->mDbFlags & DBFLAG_Vacuum ){
2376       /* This INSERT command is part of a VACUUM operation, which guarantees
2377       ** that the destination table is empty. If all indexed columns use
2378       ** collation sequence BINARY, then it can also be assumed that the
2379       ** index will be populated by inserting keys in strictly sorted
2380       ** order. In this case, instead of seeking within the b-tree as part
2381       ** of every OP_IdxInsert opcode, an OP_SeekEnd is added before the
2382       ** OP_IdxInsert to seek to the point within the b-tree where each key
2383       ** should be inserted. This is faster.
2384       **
2385       ** If any of the indexed columns use a collation sequence other than
2386       ** BINARY, this optimization is disabled. This is because the user
2387       ** might change the definition of a collation sequence and then run
2388       ** a VACUUM command. In that case keys may not be written in strictly
2389       ** sorted order.  */
2390       for(i=0; i<pSrcIdx->nColumn; i++){
2391         const char *zColl = pSrcIdx->azColl[i];
2392         if( sqlite3_stricmp(sqlite3StrBINARY, zColl) ) break;
2393       }
2394       if( i==pSrcIdx->nColumn ){
2395         idxInsFlags = OPFLAG_USESEEKRESULT;
2396         sqlite3VdbeAddOp1(v, OP_SeekEnd, iDest);
2397       }
2398     }
2399     if( !HasRowid(pSrc) && pDestIdx->idxType==2 ){
2400       idxInsFlags |= OPFLAG_NCHANGE;
2401     }
2402     sqlite3VdbeAddOp2(v, OP_IdxInsert, iDest, regData);
2403     sqlite3VdbeChangeP5(v, idxInsFlags|OPFLAG_APPEND);
2404     sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1+1); VdbeCoverage(v);
2405     sqlite3VdbeJumpHere(v, addr1);
2406     sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
2407     sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
2408   }
2409   if( emptySrcTest ) sqlite3VdbeJumpHere(v, emptySrcTest);
2410   sqlite3ReleaseTempReg(pParse, regRowid);
2411   sqlite3ReleaseTempReg(pParse, regData);
2412   if( emptyDestTest ){
2413     sqlite3AutoincrementEnd(pParse);
2414     sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_OK, 0);
2415     sqlite3VdbeJumpHere(v, emptyDestTest);
2416     sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
2417     return 0;
2418   }else{
2419     return 1;
2420   }
2421 }
2422 #endif /* SQLITE_OMIT_XFER_OPT */
2423