• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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 open a table for reading.
19 */
sqlite3OpenTable(Parse * p,int iCur,int iDb,Table * pTab,int opcode)20 void sqlite3OpenTable(
21   Parse *p,       /* Generate code into this VDBE */
22   int iCur,       /* The cursor number of the table */
23   int iDb,        /* The database index in sqlite3.aDb[] */
24   Table *pTab,    /* The table to be opened */
25   int opcode      /* OP_OpenRead or OP_OpenWrite */
26 ){
27   Vdbe *v;
28   if( IsVirtual(pTab) ) return;
29   v = sqlite3GetVdbe(p);
30   assert( opcode==OP_OpenWrite || opcode==OP_OpenRead );
31   sqlite3TableLock(p, iDb, pTab->tnum, (opcode==OP_OpenWrite)?1:0, pTab->zName);
32   sqlite3VdbeAddOp3(v, opcode, iCur, pTab->tnum, iDb);
33   sqlite3VdbeChangeP4(v, -1, SQLITE_INT_TO_PTR(pTab->nCol), P4_INT32);
34   VdbeComment((v, "%s", pTab->zName));
35 }
36 
37 /*
38 ** Return a pointer to the column affinity string associated with index
39 ** pIdx. A column affinity string has one character for each column in
40 ** the table, according to the affinity of the column:
41 **
42 **  Character      Column affinity
43 **  ------------------------------
44 **  'a'            TEXT
45 **  'b'            NONE
46 **  'c'            NUMERIC
47 **  'd'            INTEGER
48 **  'e'            REAL
49 **
50 ** An extra 'b' is appended to the end of the string to cover the
51 ** rowid that appears as the last column in every index.
52 **
53 ** Memory for the buffer containing the column index affinity string
54 ** is managed along with the rest of the Index structure. It will be
55 ** released when sqlite3DeleteIndex() is called.
56 */
sqlite3IndexAffinityStr(Vdbe * v,Index * pIdx)57 const char *sqlite3IndexAffinityStr(Vdbe *v, Index *pIdx){
58   if( !pIdx->zColAff ){
59     /* The first time a column affinity string for a particular index is
60     ** required, it is allocated and populated here. It is then stored as
61     ** a member of the Index structure for subsequent use.
62     **
63     ** The column affinity string will eventually be deleted by
64     ** sqliteDeleteIndex() when the Index structure itself is cleaned
65     ** up.
66     */
67     int n;
68     Table *pTab = pIdx->pTable;
69     sqlite3 *db = sqlite3VdbeDb(v);
70     pIdx->zColAff = (char *)sqlite3DbMallocRaw(0, pIdx->nColumn+2);
71     if( !pIdx->zColAff ){
72       db->mallocFailed = 1;
73       return 0;
74     }
75     for(n=0; n<pIdx->nColumn; n++){
76       pIdx->zColAff[n] = pTab->aCol[pIdx->aiColumn[n]].affinity;
77     }
78     pIdx->zColAff[n++] = SQLITE_AFF_NONE;
79     pIdx->zColAff[n] = 0;
80   }
81 
82   return pIdx->zColAff;
83 }
84 
85 /*
86 ** Set P4 of the most recently inserted opcode to a column affinity
87 ** string for table pTab. A column affinity string has one character
88 ** for each column indexed by the index, according to the affinity of the
89 ** column:
90 **
91 **  Character      Column affinity
92 **  ------------------------------
93 **  'a'            TEXT
94 **  'b'            NONE
95 **  'c'            NUMERIC
96 **  'd'            INTEGER
97 **  'e'            REAL
98 */
sqlite3TableAffinityStr(Vdbe * v,Table * pTab)99 void sqlite3TableAffinityStr(Vdbe *v, Table *pTab){
100   /* The first time a column affinity string for a particular table
101   ** is required, it is allocated and populated here. It is then
102   ** stored as a member of the Table structure for subsequent use.
103   **
104   ** The column affinity string will eventually be deleted by
105   ** sqlite3DeleteTable() when the Table structure itself is cleaned up.
106   */
107   if( !pTab->zColAff ){
108     char *zColAff;
109     int i;
110     sqlite3 *db = sqlite3VdbeDb(v);
111 
112     zColAff = (char *)sqlite3DbMallocRaw(0, pTab->nCol+1);
113     if( !zColAff ){
114       db->mallocFailed = 1;
115       return;
116     }
117 
118     for(i=0; i<pTab->nCol; i++){
119       zColAff[i] = pTab->aCol[i].affinity;
120     }
121     zColAff[pTab->nCol] = '\0';
122 
123     pTab->zColAff = zColAff;
124   }
125 
126   sqlite3VdbeChangeP4(v, -1, pTab->zColAff, P4_TRANSIENT);
127 }
128 
129 /*
130 ** Return non-zero if the table pTab in database iDb or any of its indices
131 ** have been opened at any point in the VDBE program beginning at location
132 ** iStartAddr throught the end of the program.  This is used to see if
133 ** a statement of the form  "INSERT INTO <iDb, pTab> SELECT ..." can
134 ** run without using temporary table for the results of the SELECT.
135 */
readsTable(Parse * p,int iStartAddr,int iDb,Table * pTab)136 static int readsTable(Parse *p, int iStartAddr, int iDb, Table *pTab){
137   Vdbe *v = sqlite3GetVdbe(p);
138   int i;
139   int iEnd = sqlite3VdbeCurrentAddr(v);
140 #ifndef SQLITE_OMIT_VIRTUALTABLE
141   VTable *pVTab = IsVirtual(pTab) ? sqlite3GetVTable(p->db, pTab) : 0;
142 #endif
143 
144   for(i=iStartAddr; i<iEnd; i++){
145     VdbeOp *pOp = sqlite3VdbeGetOp(v, i);
146     assert( pOp!=0 );
147     if( pOp->opcode==OP_OpenRead && pOp->p3==iDb ){
148       Index *pIndex;
149       int tnum = pOp->p2;
150       if( tnum==pTab->tnum ){
151         return 1;
152       }
153       for(pIndex=pTab->pIndex; pIndex; pIndex=pIndex->pNext){
154         if( tnum==pIndex->tnum ){
155           return 1;
156         }
157       }
158     }
159 #ifndef SQLITE_OMIT_VIRTUALTABLE
160     if( pOp->opcode==OP_VOpen && pOp->p4.pVtab==pVTab ){
161       assert( pOp->p4.pVtab!=0 );
162       assert( pOp->p4type==P4_VTAB );
163       return 1;
164     }
165 #endif
166   }
167   return 0;
168 }
169 
170 #ifndef SQLITE_OMIT_AUTOINCREMENT
171 /*
172 ** Locate or create an AutoincInfo structure associated with table pTab
173 ** which is in database iDb.  Return the register number for the register
174 ** that holds the maximum rowid.
175 **
176 ** There is at most one AutoincInfo structure per table even if the
177 ** same table is autoincremented multiple times due to inserts within
178 ** triggers.  A new AutoincInfo structure is created if this is the
179 ** first use of table pTab.  On 2nd and subsequent uses, the original
180 ** AutoincInfo structure is used.
181 **
182 ** Three memory locations are allocated:
183 **
184 **   (1)  Register to hold the name of the pTab table.
185 **   (2)  Register to hold the maximum ROWID of pTab.
186 **   (3)  Register to hold the rowid in sqlite_sequence of pTab
187 **
188 ** The 2nd register is the one that is returned.  That is all the
189 ** insert routine needs to know about.
190 */
autoIncBegin(Parse * pParse,int iDb,Table * pTab)191 static int autoIncBegin(
192   Parse *pParse,      /* Parsing context */
193   int iDb,            /* Index of the database holding pTab */
194   Table *pTab         /* The table we are writing to */
195 ){
196   int memId = 0;      /* Register holding maximum rowid */
197   if( pTab->tabFlags & TF_Autoincrement ){
198     Parse *pToplevel = sqlite3ParseToplevel(pParse);
199     AutoincInfo *pInfo;
200 
201     pInfo = pToplevel->pAinc;
202     while( pInfo && pInfo->pTab!=pTab ){ pInfo = pInfo->pNext; }
203     if( pInfo==0 ){
204       pInfo = sqlite3DbMallocRaw(pParse->db, sizeof(*pInfo));
205       if( pInfo==0 ) return 0;
206       pInfo->pNext = pToplevel->pAinc;
207       pToplevel->pAinc = pInfo;
208       pInfo->pTab = pTab;
209       pInfo->iDb = iDb;
210       pToplevel->nMem++;                  /* Register to hold name of table */
211       pInfo->regCtr = ++pToplevel->nMem;  /* Max rowid register */
212       pToplevel->nMem++;                  /* Rowid in sqlite_sequence */
213     }
214     memId = pInfo->regCtr;
215   }
216   return memId;
217 }
218 
219 /*
220 ** This routine generates code that will initialize all of the
221 ** register used by the autoincrement tracker.
222 */
sqlite3AutoincrementBegin(Parse * pParse)223 void sqlite3AutoincrementBegin(Parse *pParse){
224   AutoincInfo *p;            /* Information about an AUTOINCREMENT */
225   sqlite3 *db = pParse->db;  /* The database connection */
226   Db *pDb;                   /* Database only autoinc table */
227   int memId;                 /* Register holding max rowid */
228   int addr;                  /* A VDBE address */
229   Vdbe *v = pParse->pVdbe;   /* VDBE under construction */
230 
231   /* This routine is never called during trigger-generation.  It is
232   ** only called from the top-level */
233   assert( pParse->pTriggerTab==0 );
234   assert( pParse==sqlite3ParseToplevel(pParse) );
235 
236   assert( v );   /* We failed long ago if this is not so */
237   for(p = pParse->pAinc; p; p = p->pNext){
238     pDb = &db->aDb[p->iDb];
239     memId = p->regCtr;
240     assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
241     sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenRead);
242     addr = sqlite3VdbeCurrentAddr(v);
243     sqlite3VdbeAddOp4(v, OP_String8, 0, memId-1, 0, p->pTab->zName, 0);
244     sqlite3VdbeAddOp2(v, OP_Rewind, 0, addr+9);
245     sqlite3VdbeAddOp3(v, OP_Column, 0, 0, memId);
246     sqlite3VdbeAddOp3(v, OP_Ne, memId-1, addr+7, memId);
247     sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);
248     sqlite3VdbeAddOp2(v, OP_Rowid, 0, memId+1);
249     sqlite3VdbeAddOp3(v, OP_Column, 0, 1, memId);
250     sqlite3VdbeAddOp2(v, OP_Goto, 0, addr+9);
251     sqlite3VdbeAddOp2(v, OP_Next, 0, addr+2);
252     sqlite3VdbeAddOp2(v, OP_Integer, 0, memId);
253     sqlite3VdbeAddOp0(v, OP_Close);
254   }
255 }
256 
257 /*
258 ** Update the maximum rowid for an autoincrement calculation.
259 **
260 ** This routine should be called when the top of the stack holds a
261 ** new rowid that is about to be inserted.  If that new rowid is
262 ** larger than the maximum rowid in the memId memory cell, then the
263 ** memory cell is updated.  The stack is unchanged.
264 */
autoIncStep(Parse * pParse,int memId,int regRowid)265 static void autoIncStep(Parse *pParse, int memId, int regRowid){
266   if( memId>0 ){
267     sqlite3VdbeAddOp2(pParse->pVdbe, OP_MemMax, memId, regRowid);
268   }
269 }
270 
271 /*
272 ** This routine generates the code needed to write autoincrement
273 ** maximum rowid values back into the sqlite_sequence register.
274 ** Every statement that might do an INSERT into an autoincrement
275 ** table (either directly or through triggers) needs to call this
276 ** routine just before the "exit" code.
277 */
sqlite3AutoincrementEnd(Parse * pParse)278 void sqlite3AutoincrementEnd(Parse *pParse){
279   AutoincInfo *p;
280   Vdbe *v = pParse->pVdbe;
281   sqlite3 *db = pParse->db;
282 
283   assert( v );
284   for(p = pParse->pAinc; p; p = p->pNext){
285     Db *pDb = &db->aDb[p->iDb];
286     int j1, j2, j3, j4, j5;
287     int iRec;
288     int memId = p->regCtr;
289 
290     iRec = sqlite3GetTempReg(pParse);
291     assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
292     sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenWrite);
293     j1 = sqlite3VdbeAddOp1(v, OP_NotNull, memId+1);
294     j2 = sqlite3VdbeAddOp0(v, OP_Rewind);
295     j3 = sqlite3VdbeAddOp3(v, OP_Column, 0, 0, iRec);
296     j4 = sqlite3VdbeAddOp3(v, OP_Eq, memId-1, 0, iRec);
297     sqlite3VdbeAddOp2(v, OP_Next, 0, j3);
298     sqlite3VdbeJumpHere(v, j2);
299     sqlite3VdbeAddOp2(v, OP_NewRowid, 0, memId+1);
300     j5 = sqlite3VdbeAddOp0(v, OP_Goto);
301     sqlite3VdbeJumpHere(v, j4);
302     sqlite3VdbeAddOp2(v, OP_Rowid, 0, memId+1);
303     sqlite3VdbeJumpHere(v, j1);
304     sqlite3VdbeJumpHere(v, j5);
305     sqlite3VdbeAddOp3(v, OP_MakeRecord, memId-1, 2, iRec);
306     sqlite3VdbeAddOp3(v, OP_Insert, 0, iRec, memId+1);
307     sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
308     sqlite3VdbeAddOp0(v, OP_Close);
309     sqlite3ReleaseTempReg(pParse, iRec);
310   }
311 }
312 #else
313 /*
314 ** If SQLITE_OMIT_AUTOINCREMENT is defined, then the three routines
315 ** above are all no-ops
316 */
317 # define autoIncBegin(A,B,C) (0)
318 # define autoIncStep(A,B,C)
319 #endif /* SQLITE_OMIT_AUTOINCREMENT */
320 
321 
322 /* Forward declaration */
323 static int xferOptimization(
324   Parse *pParse,        /* Parser context */
325   Table *pDest,         /* The table we are inserting into */
326   Select *pSelect,      /* A SELECT statement to use as the data source */
327   int onError,          /* How to handle constraint errors */
328   int iDbDest           /* The database of pDest */
329 );
330 
331 /*
332 ** This routine is call to handle SQL of the following forms:
333 **
334 **    insert into TABLE (IDLIST) values(EXPRLIST)
335 **    insert into TABLE (IDLIST) select
336 **
337 ** The IDLIST following the table name is always optional.  If omitted,
338 ** then a list of all columns for the table is substituted.  The IDLIST
339 ** appears in the pColumn parameter.  pColumn is NULL if IDLIST is omitted.
340 **
341 ** The pList parameter holds EXPRLIST in the first form of the INSERT
342 ** statement above, and pSelect is NULL.  For the second form, pList is
343 ** NULL and pSelect is a pointer to the select statement used to generate
344 ** data for the insert.
345 **
346 ** The code generated follows one of four templates.  For a simple
347 ** select with data coming from a VALUES clause, the code executes
348 ** once straight down through.  Pseudo-code follows (we call this
349 ** the "1st template"):
350 **
351 **         open write cursor to <table> and its indices
352 **         puts VALUES clause expressions onto the stack
353 **         write the resulting record into <table>
354 **         cleanup
355 **
356 ** The three remaining templates assume the statement is of the form
357 **
358 **   INSERT INTO <table> SELECT ...
359 **
360 ** If the SELECT clause is of the restricted form "SELECT * FROM <table2>" -
361 ** in other words if the SELECT pulls all columns from a single table
362 ** and there is no WHERE or LIMIT or GROUP BY or ORDER BY clauses, and
363 ** if <table2> and <table1> are distinct tables but have identical
364 ** schemas, including all the same indices, then a special optimization
365 ** is invoked that copies raw records from <table2> over to <table1>.
366 ** See the xferOptimization() function for the implementation of this
367 ** template.  This is the 2nd template.
368 **
369 **         open a write cursor to <table>
370 **         open read cursor on <table2>
371 **         transfer all records in <table2> over to <table>
372 **         close cursors
373 **         foreach index on <table>
374 **           open a write cursor on the <table> index
375 **           open a read cursor on the corresponding <table2> index
376 **           transfer all records from the read to the write cursors
377 **           close cursors
378 **         end foreach
379 **
380 ** The 3rd template is for when the second template does not apply
381 ** and the SELECT clause does not read from <table> at any time.
382 ** The generated code follows this template:
383 **
384 **         EOF <- 0
385 **         X <- A
386 **         goto B
387 **      A: setup for the SELECT
388 **         loop over the rows in the SELECT
389 **           load values into registers R..R+n
390 **           yield X
391 **         end loop
392 **         cleanup after the SELECT
393 **         EOF <- 1
394 **         yield X
395 **         goto A
396 **      B: open write cursor to <table> and its indices
397 **      C: yield X
398 **         if EOF goto D
399 **         insert the select result into <table> from R..R+n
400 **         goto C
401 **      D: cleanup
402 **
403 ** The 4th template is used if the insert statement takes its
404 ** values from a SELECT but the data is being inserted into a table
405 ** that is also read as part of the SELECT.  In the third form,
406 ** we have to use a intermediate table to store the results of
407 ** the select.  The template is like this:
408 **
409 **         EOF <- 0
410 **         X <- A
411 **         goto B
412 **      A: setup for the SELECT
413 **         loop over the tables in the SELECT
414 **           load value into register R..R+n
415 **           yield X
416 **         end loop
417 **         cleanup after the SELECT
418 **         EOF <- 1
419 **         yield X
420 **         halt-error
421 **      B: open temp table
422 **      L: yield X
423 **         if EOF goto M
424 **         insert row from R..R+n into temp table
425 **         goto L
426 **      M: open write cursor to <table> and its indices
427 **         rewind temp table
428 **      C: loop over rows of intermediate table
429 **           transfer values form intermediate table into <table>
430 **         end loop
431 **      D: cleanup
432 */
sqlite3Insert(Parse * pParse,SrcList * pTabList,ExprList * pList,Select * pSelect,IdList * pColumn,int onError)433 void sqlite3Insert(
434   Parse *pParse,        /* Parser context */
435   SrcList *pTabList,    /* Name of table into which we are inserting */
436   ExprList *pList,      /* List of values to be inserted */
437   Select *pSelect,      /* A SELECT statement to use as the data source */
438   IdList *pColumn,      /* Column names corresponding to IDLIST. */
439   int onError           /* How to handle constraint errors */
440 ){
441   sqlite3 *db;          /* The main database structure */
442   Table *pTab;          /* The table to insert into.  aka TABLE */
443   char *zTab;           /* Name of the table into which we are inserting */
444   const char *zDb;      /* Name of the database holding this table */
445   int i, j, idx;        /* Loop counters */
446   Vdbe *v;              /* Generate code into this virtual machine */
447   Index *pIdx;          /* For looping over indices of the table */
448   int nColumn;          /* Number of columns in the data */
449   int nHidden = 0;      /* Number of hidden columns if TABLE is virtual */
450   int baseCur = 0;      /* VDBE Cursor number for pTab */
451   int keyColumn = -1;   /* Column that is the INTEGER PRIMARY KEY */
452   int endOfLoop;        /* Label for the end of the insertion loop */
453   int useTempTable = 0; /* Store SELECT results in intermediate table */
454   int srcTab = 0;       /* Data comes from this temporary cursor if >=0 */
455   int addrInsTop = 0;   /* Jump to label "D" */
456   int addrCont = 0;     /* Top of insert loop. Label "C" in templates 3 and 4 */
457   int addrSelect = 0;   /* Address of coroutine that implements the SELECT */
458   SelectDest dest;      /* Destination for SELECT on rhs of INSERT */
459   int iDb;              /* Index of database holding TABLE */
460   Db *pDb;              /* The database containing table being inserted into */
461   int appendFlag = 0;   /* True if the insert is likely to be an append */
462 
463   /* Register allocations */
464   int regFromSelect = 0;/* Base register for data coming from SELECT */
465   int regAutoinc = 0;   /* Register holding the AUTOINCREMENT counter */
466   int regRowCount = 0;  /* Memory cell used for the row counter */
467   int regIns;           /* Block of regs holding rowid+data being inserted */
468   int regRowid;         /* registers holding insert rowid */
469   int regData;          /* register holding first column to insert */
470   int regEof = 0;       /* Register recording end of SELECT data */
471   int *aRegIdx = 0;     /* One register allocated to each index */
472 
473 #ifndef SQLITE_OMIT_TRIGGER
474   int isView;                 /* True if attempting to insert into a view */
475   Trigger *pTrigger;          /* List of triggers on pTab, if required */
476   int tmask;                  /* Mask of trigger times */
477 #endif
478 
479   db = pParse->db;
480   memset(&dest, 0, sizeof(dest));
481   if( pParse->nErr || db->mallocFailed ){
482     goto insert_cleanup;
483   }
484 
485   /* Locate the table into which we will be inserting new information.
486   */
487   assert( pTabList->nSrc==1 );
488   zTab = pTabList->a[0].zName;
489   if( NEVER(zTab==0) ) goto insert_cleanup;
490   pTab = sqlite3SrcListLookup(pParse, pTabList);
491   if( pTab==0 ){
492     goto insert_cleanup;
493   }
494   iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
495   assert( iDb<db->nDb );
496   pDb = &db->aDb[iDb];
497   zDb = pDb->zName;
498   if( sqlite3AuthCheck(pParse, SQLITE_INSERT, pTab->zName, 0, zDb) ){
499     goto insert_cleanup;
500   }
501 
502   /* Figure out if we have any triggers and if the table being
503   ** inserted into is a view
504   */
505 #ifndef SQLITE_OMIT_TRIGGER
506   pTrigger = sqlite3TriggersExist(pParse, pTab, TK_INSERT, 0, &tmask);
507   isView = pTab->pSelect!=0;
508 #else
509 # define pTrigger 0
510 # define tmask 0
511 # define isView 0
512 #endif
513 #ifdef SQLITE_OMIT_VIEW
514 # undef isView
515 # define isView 0
516 #endif
517   assert( (pTrigger && tmask) || (pTrigger==0 && tmask==0) );
518 
519   /* If pTab is really a view, make sure it has been initialized.
520   ** ViewGetColumnNames() is a no-op if pTab is not a view (or virtual
521   ** module table).
522   */
523   if( sqlite3ViewGetColumnNames(pParse, pTab) ){
524     goto insert_cleanup;
525   }
526 
527   /* Ensure that:
528   *  (a) the table is not read-only,
529   *  (b) that if it is a view then ON INSERT triggers exist
530   */
531   if( sqlite3IsReadOnly(pParse, pTab, tmask) ){
532     goto insert_cleanup;
533   }
534 
535   /* Allocate a VDBE
536   */
537   v = sqlite3GetVdbe(pParse);
538   if( v==0 ) goto insert_cleanup;
539   if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
540   sqlite3BeginWriteOperation(pParse, pSelect || pTrigger, iDb);
541 
542 #ifndef SQLITE_OMIT_XFER_OPT
543   /* If the statement is of the form
544   **
545   **       INSERT INTO <table1> SELECT * FROM <table2>;
546   **
547   ** Then special optimizations can be applied that make the transfer
548   ** very fast and which reduce fragmentation of indices.
549   **
550   ** This is the 2nd template.
551   */
552   if( pColumn==0 && xferOptimization(pParse, pTab, pSelect, onError, iDb) ){
553     assert( !pTrigger );
554     assert( pList==0 );
555     goto insert_end;
556   }
557 #endif /* SQLITE_OMIT_XFER_OPT */
558 
559   /* If this is an AUTOINCREMENT table, look up the sequence number in the
560   ** sqlite_sequence table and store it in memory cell regAutoinc.
561   */
562   regAutoinc = autoIncBegin(pParse, iDb, pTab);
563 
564   /* Figure out how many columns of data are supplied.  If the data
565   ** is coming from a SELECT statement, then generate a co-routine that
566   ** produces a single row of the SELECT on each invocation.  The
567   ** co-routine is the common header to the 3rd and 4th templates.
568   */
569   if( pSelect ){
570     /* Data is coming from a SELECT.  Generate code to implement that SELECT
571     ** as a co-routine.  The code is common to both the 3rd and 4th
572     ** templates:
573     **
574     **         EOF <- 0
575     **         X <- A
576     **         goto B
577     **      A: setup for the SELECT
578     **         loop over the tables in the SELECT
579     **           load value into register R..R+n
580     **           yield X
581     **         end loop
582     **         cleanup after the SELECT
583     **         EOF <- 1
584     **         yield X
585     **         halt-error
586     **
587     ** On each invocation of the co-routine, it puts a single row of the
588     ** SELECT result into registers dest.iMem...dest.iMem+dest.nMem-1.
589     ** (These output registers are allocated by sqlite3Select().)  When
590     ** the SELECT completes, it sets the EOF flag stored in regEof.
591     */
592     int rc, j1;
593 
594     regEof = ++pParse->nMem;
595     sqlite3VdbeAddOp2(v, OP_Integer, 0, regEof);      /* EOF <- 0 */
596     VdbeComment((v, "SELECT eof flag"));
597     sqlite3SelectDestInit(&dest, SRT_Coroutine, ++pParse->nMem);
598     addrSelect = sqlite3VdbeCurrentAddr(v)+2;
599     sqlite3VdbeAddOp2(v, OP_Integer, addrSelect-1, dest.iParm);
600     j1 = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
601     VdbeComment((v, "Jump over SELECT coroutine"));
602 
603     /* Resolve the expressions in the SELECT statement and execute it. */
604     rc = sqlite3Select(pParse, pSelect, &dest);
605     assert( pParse->nErr==0 || rc );
606     if( rc || NEVER(pParse->nErr) || db->mallocFailed ){
607       goto insert_cleanup;
608     }
609     sqlite3VdbeAddOp2(v, OP_Integer, 1, regEof);         /* EOF <- 1 */
610     sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);   /* yield X */
611     sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_INTERNAL, OE_Abort);
612     VdbeComment((v, "End of SELECT coroutine"));
613     sqlite3VdbeJumpHere(v, j1);                          /* label B: */
614 
615     regFromSelect = dest.iMem;
616     assert( pSelect->pEList );
617     nColumn = pSelect->pEList->nExpr;
618     assert( dest.nMem==nColumn );
619 
620     /* Set useTempTable to TRUE if the result of the SELECT statement
621     ** should be written into a temporary table (template 4).  Set to
622     ** FALSE if each* row of the SELECT can be written directly into
623     ** the destination table (template 3).
624     **
625     ** A temp table must be used if the table being updated is also one
626     ** of the tables being read by the SELECT statement.  Also use a
627     ** temp table in the case of row triggers.
628     */
629     if( pTrigger || readsTable(pParse, addrSelect, iDb, pTab) ){
630       useTempTable = 1;
631     }
632 
633     if( useTempTable ){
634       /* Invoke the coroutine to extract information from the SELECT
635       ** and add it to a transient table srcTab.  The code generated
636       ** here is from the 4th template:
637       **
638       **      B: open temp table
639       **      L: yield X
640       **         if EOF goto M
641       **         insert row from R..R+n into temp table
642       **         goto L
643       **      M: ...
644       */
645       int regRec;          /* Register to hold packed record */
646       int regTempRowid;    /* Register to hold temp table ROWID */
647       int addrTop;         /* Label "L" */
648       int addrIf;          /* Address of jump to M */
649 
650       srcTab = pParse->nTab++;
651       regRec = sqlite3GetTempReg(pParse);
652       regTempRowid = sqlite3GetTempReg(pParse);
653       sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
654       addrTop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);
655       addrIf = sqlite3VdbeAddOp1(v, OP_If, regEof);
656       sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
657       sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regTempRowid);
658       sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regTempRowid);
659       sqlite3VdbeAddOp2(v, OP_Goto, 0, addrTop);
660       sqlite3VdbeJumpHere(v, addrIf);
661       sqlite3ReleaseTempReg(pParse, regRec);
662       sqlite3ReleaseTempReg(pParse, regTempRowid);
663     }
664   }else{
665     /* This is the case if the data for the INSERT is coming from a VALUES
666     ** clause
667     */
668     NameContext sNC;
669     memset(&sNC, 0, sizeof(sNC));
670     sNC.pParse = pParse;
671     srcTab = -1;
672     assert( useTempTable==0 );
673     nColumn = pList ? pList->nExpr : 0;
674     for(i=0; i<nColumn; i++){
675       if( sqlite3ResolveExprNames(&sNC, pList->a[i].pExpr) ){
676         goto insert_cleanup;
677       }
678     }
679   }
680 
681   /* Make sure the number of columns in the source data matches the number
682   ** of columns to be inserted into the table.
683   */
684   if( IsVirtual(pTab) ){
685     for(i=0; i<pTab->nCol; i++){
686       nHidden += (IsHiddenColumn(&pTab->aCol[i]) ? 1 : 0);
687     }
688   }
689   if( pColumn==0 && nColumn && nColumn!=(pTab->nCol-nHidden) ){
690     sqlite3ErrorMsg(pParse,
691        "table %S has %d columns but %d values were supplied",
692        pTabList, 0, pTab->nCol-nHidden, nColumn);
693     goto insert_cleanup;
694   }
695   if( pColumn!=0 && nColumn!=pColumn->nId ){
696     sqlite3ErrorMsg(pParse, "%d values for %d columns", nColumn, pColumn->nId);
697     goto insert_cleanup;
698   }
699 
700   /* If the INSERT statement included an IDLIST term, then make sure
701   ** all elements of the IDLIST really are columns of the table and
702   ** remember the column indices.
703   **
704   ** If the table has an INTEGER PRIMARY KEY column and that column
705   ** is named in the IDLIST, then record in the keyColumn variable
706   ** the index into IDLIST of the primary key column.  keyColumn is
707   ** the index of the primary key as it appears in IDLIST, not as
708   ** is appears in the original table.  (The index of the primary
709   ** key in the original table is pTab->iPKey.)
710   */
711   if( pColumn ){
712     for(i=0; i<pColumn->nId; i++){
713       pColumn->a[i].idx = -1;
714     }
715     for(i=0; i<pColumn->nId; i++){
716       for(j=0; j<pTab->nCol; j++){
717         if( sqlite3StrICmp(pColumn->a[i].zName, pTab->aCol[j].zName)==0 ){
718           pColumn->a[i].idx = j;
719           if( j==pTab->iPKey ){
720             keyColumn = i;
721           }
722           break;
723         }
724       }
725       if( j>=pTab->nCol ){
726         if( sqlite3IsRowid(pColumn->a[i].zName) ){
727           keyColumn = i;
728         }else{
729           sqlite3ErrorMsg(pParse, "table %S has no column named %s",
730               pTabList, 0, pColumn->a[i].zName);
731           pParse->checkSchema = 1;
732           goto insert_cleanup;
733         }
734       }
735     }
736   }
737 
738   /* If there is no IDLIST term but the table has an integer primary
739   ** key, the set the keyColumn variable to the primary key column index
740   ** in the original table definition.
741   */
742   if( pColumn==0 && nColumn>0 ){
743     keyColumn = pTab->iPKey;
744   }
745 
746   /* Initialize the count of rows to be inserted
747   */
748   if( db->flags & SQLITE_CountRows ){
749     regRowCount = ++pParse->nMem;
750     sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
751   }
752 
753   /* If this is not a view, open the table and and all indices */
754   if( !isView ){
755     int nIdx;
756 
757     baseCur = pParse->nTab;
758     nIdx = sqlite3OpenTableAndIndices(pParse, pTab, baseCur, OP_OpenWrite);
759     aRegIdx = sqlite3DbMallocRaw(db, sizeof(int)*(nIdx+1));
760     if( aRegIdx==0 ){
761       goto insert_cleanup;
762     }
763     for(i=0; i<nIdx; i++){
764       aRegIdx[i] = ++pParse->nMem;
765     }
766   }
767 
768   /* This is the top of the main insertion loop */
769   if( useTempTable ){
770     /* This block codes the top of loop only.  The complete loop is the
771     ** following pseudocode (template 4):
772     **
773     **         rewind temp table
774     **      C: loop over rows of intermediate table
775     **           transfer values form intermediate table into <table>
776     **         end loop
777     **      D: ...
778     */
779     addrInsTop = sqlite3VdbeAddOp1(v, OP_Rewind, srcTab);
780     addrCont = sqlite3VdbeCurrentAddr(v);
781   }else if( pSelect ){
782     /* This block codes the top of loop only.  The complete loop is the
783     ** following pseudocode (template 3):
784     **
785     **      C: yield X
786     **         if EOF goto D
787     **         insert the select result into <table> from R..R+n
788     **         goto C
789     **      D: ...
790     */
791     addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);
792     addrInsTop = sqlite3VdbeAddOp1(v, OP_If, regEof);
793   }
794 
795   /* Allocate registers for holding the rowid of the new row,
796   ** the content of the new row, and the assemblied row record.
797   */
798   regRowid = regIns = pParse->nMem+1;
799   pParse->nMem += pTab->nCol + 1;
800   if( IsVirtual(pTab) ){
801     regRowid++;
802     pParse->nMem++;
803   }
804   regData = regRowid+1;
805 
806   /* Run the BEFORE and INSTEAD OF triggers, if there are any
807   */
808   endOfLoop = sqlite3VdbeMakeLabel(v);
809   if( tmask & TRIGGER_BEFORE ){
810     int regCols = sqlite3GetTempRange(pParse, pTab->nCol+1);
811 
812     /* build the NEW.* reference row.  Note that if there is an INTEGER
813     ** PRIMARY KEY into which a NULL is being inserted, that NULL will be
814     ** translated into a unique ID for the row.  But on a BEFORE trigger,
815     ** we do not know what the unique ID will be (because the insert has
816     ** not happened yet) so we substitute a rowid of -1
817     */
818     if( keyColumn<0 ){
819       sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
820     }else{
821       int j1;
822       if( useTempTable ){
823         sqlite3VdbeAddOp3(v, OP_Column, srcTab, keyColumn, regCols);
824       }else{
825         assert( pSelect==0 );  /* Otherwise useTempTable is true */
826         sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr, regCols);
827       }
828       j1 = sqlite3VdbeAddOp1(v, OP_NotNull, regCols);
829       sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
830       sqlite3VdbeJumpHere(v, j1);
831       sqlite3VdbeAddOp1(v, OP_MustBeInt, regCols);
832     }
833 
834     /* Cannot have triggers on a virtual table. If it were possible,
835     ** this block would have to account for hidden column.
836     */
837     assert( !IsVirtual(pTab) );
838 
839     /* Create the new column data
840     */
841     for(i=0; i<pTab->nCol; i++){
842       if( pColumn==0 ){
843         j = i;
844       }else{
845         for(j=0; j<pColumn->nId; j++){
846           if( pColumn->a[j].idx==i ) break;
847         }
848       }
849       if( (!useTempTable && !pList) || (pColumn && j>=pColumn->nId) ){
850         sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regCols+i+1);
851       }else if( useTempTable ){
852         sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, regCols+i+1);
853       }else{
854         assert( pSelect==0 ); /* Otherwise useTempTable is true */
855         sqlite3ExprCodeAndCache(pParse, pList->a[j].pExpr, regCols+i+1);
856       }
857     }
858 
859     /* If this is an INSERT on a view with an INSTEAD OF INSERT trigger,
860     ** do not attempt any conversions before assembling the record.
861     ** If this is a real table, attempt conversions as required by the
862     ** table column affinities.
863     */
864     if( !isView ){
865       sqlite3VdbeAddOp2(v, OP_Affinity, regCols+1, pTab->nCol);
866       sqlite3TableAffinityStr(v, pTab);
867     }
868 
869     /* Fire BEFORE or INSTEAD OF triggers */
870     sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_BEFORE,
871         pTab, regCols-pTab->nCol-1, onError, endOfLoop);
872 
873     sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol+1);
874   }
875 
876   /* Push the record number for the new entry onto the stack.  The
877   ** record number is a randomly generate integer created by NewRowid
878   ** except when the table has an INTEGER PRIMARY KEY column, in which
879   ** case the record number is the same as that column.
880   */
881   if( !isView ){
882     if( IsVirtual(pTab) ){
883       /* The row that the VUpdate opcode will delete: none */
884       sqlite3VdbeAddOp2(v, OP_Null, 0, regIns);
885     }
886     if( keyColumn>=0 ){
887       if( useTempTable ){
888         sqlite3VdbeAddOp3(v, OP_Column, srcTab, keyColumn, regRowid);
889       }else if( pSelect ){
890         sqlite3VdbeAddOp2(v, OP_SCopy, regFromSelect+keyColumn, regRowid);
891       }else{
892         VdbeOp *pOp;
893         sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr, regRowid);
894         pOp = sqlite3VdbeGetOp(v, -1);
895         if( ALWAYS(pOp) && pOp->opcode==OP_Null && !IsVirtual(pTab) ){
896           appendFlag = 1;
897           pOp->opcode = OP_NewRowid;
898           pOp->p1 = baseCur;
899           pOp->p2 = regRowid;
900           pOp->p3 = regAutoinc;
901         }
902       }
903       /* If the PRIMARY KEY expression is NULL, then use OP_NewRowid
904       ** to generate a unique primary key value.
905       */
906       if( !appendFlag ){
907         int j1;
908         if( !IsVirtual(pTab) ){
909           j1 = sqlite3VdbeAddOp1(v, OP_NotNull, regRowid);
910           sqlite3VdbeAddOp3(v, OP_NewRowid, baseCur, regRowid, regAutoinc);
911           sqlite3VdbeJumpHere(v, j1);
912         }else{
913           j1 = sqlite3VdbeCurrentAddr(v);
914           sqlite3VdbeAddOp2(v, OP_IsNull, regRowid, j1+2);
915         }
916         sqlite3VdbeAddOp1(v, OP_MustBeInt, regRowid);
917       }
918     }else if( IsVirtual(pTab) ){
919       sqlite3VdbeAddOp2(v, OP_Null, 0, regRowid);
920     }else{
921       sqlite3VdbeAddOp3(v, OP_NewRowid, baseCur, regRowid, regAutoinc);
922       appendFlag = 1;
923     }
924     autoIncStep(pParse, regAutoinc, regRowid);
925 
926     /* Push onto the stack, data for all columns of the new entry, beginning
927     ** with the first column.
928     */
929     nHidden = 0;
930     for(i=0; i<pTab->nCol; i++){
931       int iRegStore = regRowid+1+i;
932       if( i==pTab->iPKey ){
933         /* The value of the INTEGER PRIMARY KEY column is always a NULL.
934         ** Whenever this column is read, the record number will be substituted
935         ** in its place.  So will fill this column with a NULL to avoid
936         ** taking up data space with information that will never be used. */
937         sqlite3VdbeAddOp2(v, OP_Null, 0, iRegStore);
938         continue;
939       }
940       if( pColumn==0 ){
941         if( IsHiddenColumn(&pTab->aCol[i]) ){
942           assert( IsVirtual(pTab) );
943           j = -1;
944           nHidden++;
945         }else{
946           j = i - nHidden;
947         }
948       }else{
949         for(j=0; j<pColumn->nId; j++){
950           if( pColumn->a[j].idx==i ) break;
951         }
952       }
953       if( j<0 || nColumn==0 || (pColumn && j>=pColumn->nId) ){
954         sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, iRegStore);
955       }else if( useTempTable ){
956         sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, iRegStore);
957       }else if( pSelect ){
958         sqlite3VdbeAddOp2(v, OP_SCopy, regFromSelect+j, iRegStore);
959       }else{
960         sqlite3ExprCode(pParse, pList->a[j].pExpr, iRegStore);
961       }
962     }
963 
964     /* Generate code to check constraints and generate index keys and
965     ** do the insertion.
966     */
967 #ifndef SQLITE_OMIT_VIRTUALTABLE
968     if( IsVirtual(pTab) ){
969       const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
970       sqlite3VtabMakeWritable(pParse, pTab);
971       sqlite3VdbeAddOp4(v, OP_VUpdate, 1, pTab->nCol+2, regIns, pVTab, P4_VTAB);
972       sqlite3MayAbort(pParse);
973     }else
974 #endif
975     {
976       int isReplace;    /* Set to true if constraints may cause a replace */
977       sqlite3GenerateConstraintChecks(pParse, pTab, baseCur, regIns, aRegIdx,
978           keyColumn>=0, 0, onError, endOfLoop, &isReplace
979       );
980       sqlite3FkCheck(pParse, pTab, 0, regIns);
981       sqlite3CompleteInsertion(
982           pParse, pTab, baseCur, regIns, aRegIdx, 0, appendFlag, isReplace==0
983       );
984     }
985   }
986 
987   /* Update the count of rows that are inserted
988   */
989   if( (db->flags & SQLITE_CountRows)!=0 ){
990     sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
991   }
992 
993   if( pTrigger ){
994     /* Code AFTER triggers */
995     sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_AFTER,
996         pTab, regData-2-pTab->nCol, onError, endOfLoop);
997   }
998 
999   /* The bottom of the main insertion loop, if the data source
1000   ** is a SELECT statement.
1001   */
1002   sqlite3VdbeResolveLabel(v, endOfLoop);
1003   if( useTempTable ){
1004     sqlite3VdbeAddOp2(v, OP_Next, srcTab, addrCont);
1005     sqlite3VdbeJumpHere(v, addrInsTop);
1006     sqlite3VdbeAddOp1(v, OP_Close, srcTab);
1007   }else if( pSelect ){
1008     sqlite3VdbeAddOp2(v, OP_Goto, 0, addrCont);
1009     sqlite3VdbeJumpHere(v, addrInsTop);
1010   }
1011 
1012   if( !IsVirtual(pTab) && !isView ){
1013     /* Close all tables opened */
1014     sqlite3VdbeAddOp1(v, OP_Close, baseCur);
1015     for(idx=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, idx++){
1016       sqlite3VdbeAddOp1(v, OP_Close, idx+baseCur);
1017     }
1018   }
1019 
1020 insert_end:
1021   /* Update the sqlite_sequence table by storing the content of the
1022   ** maximum rowid counter values recorded while inserting into
1023   ** autoincrement tables.
1024   */
1025   if( pParse->nested==0 && pParse->pTriggerTab==0 ){
1026     sqlite3AutoincrementEnd(pParse);
1027   }
1028 
1029   /*
1030   ** Return the number of rows inserted. If this routine is
1031   ** generating code because of a call to sqlite3NestedParse(), do not
1032   ** invoke the callback function.
1033   */
1034   if( (db->flags&SQLITE_CountRows) && !pParse->nested && !pParse->pTriggerTab ){
1035     sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
1036     sqlite3VdbeSetNumCols(v, 1);
1037     sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows inserted", SQLITE_STATIC);
1038   }
1039 
1040 insert_cleanup:
1041   sqlite3SrcListDelete(db, pTabList);
1042   sqlite3ExprListDelete(db, pList);
1043   sqlite3SelectDelete(db, pSelect);
1044   sqlite3IdListDelete(db, pColumn);
1045   sqlite3DbFree(db, aRegIdx);
1046 }
1047 
1048 /* Make sure "isView" and other macros defined above are undefined. Otherwise
1049 ** thely may interfere with compilation of other functions in this file
1050 ** (or in another file, if this file becomes part of the amalgamation).  */
1051 #ifdef isView
1052  #undef isView
1053 #endif
1054 #ifdef pTrigger
1055  #undef pTrigger
1056 #endif
1057 #ifdef tmask
1058  #undef tmask
1059 #endif
1060 
1061 
1062 /*
1063 ** Generate code to do constraint checks prior to an INSERT or an UPDATE.
1064 **
1065 ** The input is a range of consecutive registers as follows:
1066 **
1067 **    1.  The rowid of the row after the update.
1068 **
1069 **    2.  The data in the first column of the entry after the update.
1070 **
1071 **    i.  Data from middle columns...
1072 **
1073 **    N.  The data in the last column of the entry after the update.
1074 **
1075 ** The regRowid parameter is the index of the register containing (1).
1076 **
1077 ** If isUpdate is true and rowidChng is non-zero, then rowidChng contains
1078 ** the address of a register containing the rowid before the update takes
1079 ** place. isUpdate is true for UPDATEs and false for INSERTs. If isUpdate
1080 ** is false, indicating an INSERT statement, then a non-zero rowidChng
1081 ** indicates that the rowid was explicitly specified as part of the
1082 ** INSERT statement. If rowidChng is false, it means that  the rowid is
1083 ** computed automatically in an insert or that the rowid value is not
1084 ** modified by an update.
1085 **
1086 ** The code generated by this routine store new index entries into
1087 ** registers identified by aRegIdx[].  No index entry is created for
1088 ** indices where aRegIdx[i]==0.  The order of indices in aRegIdx[] is
1089 ** the same as the order of indices on the linked list of indices
1090 ** attached to the table.
1091 **
1092 ** This routine also generates code to check constraints.  NOT NULL,
1093 ** CHECK, and UNIQUE constraints are all checked.  If a constraint fails,
1094 ** then the appropriate action is performed.  There are five possible
1095 ** actions: ROLLBACK, ABORT, FAIL, REPLACE, and IGNORE.
1096 **
1097 **  Constraint type  Action       What Happens
1098 **  ---------------  ----------   ----------------------------------------
1099 **  any              ROLLBACK     The current transaction is rolled back and
1100 **                                sqlite3_exec() returns immediately with a
1101 **                                return code of SQLITE_CONSTRAINT.
1102 **
1103 **  any              ABORT        Back out changes from the current command
1104 **                                only (do not do a complete rollback) then
1105 **                                cause sqlite3_exec() to return immediately
1106 **                                with SQLITE_CONSTRAINT.
1107 **
1108 **  any              FAIL         Sqlite_exec() returns immediately with a
1109 **                                return code of SQLITE_CONSTRAINT.  The
1110 **                                transaction is not rolled back and any
1111 **                                prior changes are retained.
1112 **
1113 **  any              IGNORE       The record number and data is popped from
1114 **                                the stack and there is an immediate jump
1115 **                                to label ignoreDest.
1116 **
1117 **  NOT NULL         REPLACE      The NULL value is replace by the default
1118 **                                value for that column.  If the default value
1119 **                                is NULL, the action is the same as ABORT.
1120 **
1121 **  UNIQUE           REPLACE      The other row that conflicts with the row
1122 **                                being inserted is removed.
1123 **
1124 **  CHECK            REPLACE      Illegal.  The results in an exception.
1125 **
1126 ** Which action to take is determined by the overrideError parameter.
1127 ** Or if overrideError==OE_Default, then the pParse->onError parameter
1128 ** is used.  Or if pParse->onError==OE_Default then the onError value
1129 ** for the constraint is used.
1130 **
1131 ** The calling routine must open a read/write cursor for pTab with
1132 ** cursor number "baseCur".  All indices of pTab must also have open
1133 ** read/write cursors with cursor number baseCur+i for the i-th cursor.
1134 ** Except, if there is no possibility of a REPLACE action then
1135 ** cursors do not need to be open for indices where aRegIdx[i]==0.
1136 */
sqlite3GenerateConstraintChecks(Parse * pParse,Table * pTab,int baseCur,int regRowid,int * aRegIdx,int rowidChng,int isUpdate,int overrideError,int ignoreDest,int * pbMayReplace)1137 void sqlite3GenerateConstraintChecks(
1138   Parse *pParse,      /* The parser context */
1139   Table *pTab,        /* the table into which we are inserting */
1140   int baseCur,        /* Index of a read/write cursor pointing at pTab */
1141   int regRowid,       /* Index of the range of input registers */
1142   int *aRegIdx,       /* Register used by each index.  0 for unused indices */
1143   int rowidChng,      /* True if the rowid might collide with existing entry */
1144   int isUpdate,       /* True for UPDATE, False for INSERT */
1145   int overrideError,  /* Override onError to this if not OE_Default */
1146   int ignoreDest,     /* Jump to this label on an OE_Ignore resolution */
1147   int *pbMayReplace   /* OUT: Set to true if constraint may cause a replace */
1148 ){
1149   int i;              /* loop counter */
1150   Vdbe *v;            /* VDBE under constrution */
1151   int nCol;           /* Number of columns */
1152   int onError;        /* Conflict resolution strategy */
1153   int j1;             /* Addresss of jump instruction */
1154   int j2 = 0, j3;     /* Addresses of jump instructions */
1155   int regData;        /* Register containing first data column */
1156   int iCur;           /* Table cursor number */
1157   Index *pIdx;         /* Pointer to one of the indices */
1158   int seenReplace = 0; /* True if REPLACE is used to resolve INT PK conflict */
1159   int regOldRowid = (rowidChng && isUpdate) ? rowidChng : regRowid;
1160 
1161   v = sqlite3GetVdbe(pParse);
1162   assert( v!=0 );
1163   assert( pTab->pSelect==0 );  /* This table is not a VIEW */
1164   nCol = pTab->nCol;
1165   regData = regRowid + 1;
1166 
1167   /* Test all NOT NULL constraints.
1168   */
1169   for(i=0; i<nCol; i++){
1170     if( i==pTab->iPKey ){
1171       continue;
1172     }
1173     onError = pTab->aCol[i].notNull;
1174     if( onError==OE_None ) continue;
1175     if( overrideError!=OE_Default ){
1176       onError = overrideError;
1177     }else if( onError==OE_Default ){
1178       onError = OE_Abort;
1179     }
1180     if( onError==OE_Replace && pTab->aCol[i].pDflt==0 ){
1181       onError = OE_Abort;
1182     }
1183     assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
1184         || onError==OE_Ignore || onError==OE_Replace );
1185     switch( onError ){
1186       case OE_Abort:
1187         sqlite3MayAbort(pParse);
1188       case OE_Rollback:
1189       case OE_Fail: {
1190         char *zMsg;
1191         sqlite3VdbeAddOp3(v, OP_HaltIfNull,
1192                                   SQLITE_CONSTRAINT, onError, regData+i);
1193         zMsg = sqlite3MPrintf(pParse->db, "%s.%s may not be NULL",
1194                               pTab->zName, pTab->aCol[i].zName);
1195         sqlite3VdbeChangeP4(v, -1, zMsg, P4_DYNAMIC);
1196         break;
1197       }
1198       case OE_Ignore: {
1199         sqlite3VdbeAddOp2(v, OP_IsNull, regData+i, ignoreDest);
1200         break;
1201       }
1202       default: {
1203         assert( onError==OE_Replace );
1204         j1 = sqlite3VdbeAddOp1(v, OP_NotNull, regData+i);
1205         sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regData+i);
1206         sqlite3VdbeJumpHere(v, j1);
1207         break;
1208       }
1209     }
1210   }
1211 
1212   /* Test all CHECK constraints
1213   */
1214 #ifndef SQLITE_OMIT_CHECK
1215   if( pTab->pCheck && (pParse->db->flags & SQLITE_IgnoreChecks)==0 ){
1216     int allOk = sqlite3VdbeMakeLabel(v);
1217     pParse->ckBase = regData;
1218     sqlite3ExprIfTrue(pParse, pTab->pCheck, allOk, SQLITE_JUMPIFNULL);
1219     onError = overrideError!=OE_Default ? overrideError : OE_Abort;
1220     if( onError==OE_Ignore ){
1221       sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
1222     }else{
1223       if( onError==OE_Replace ) onError = OE_Abort; /* IMP: R-15569-63625 */
1224       sqlite3HaltConstraint(pParse, onError, 0, 0);
1225     }
1226     sqlite3VdbeResolveLabel(v, allOk);
1227   }
1228 #endif /* !defined(SQLITE_OMIT_CHECK) */
1229 
1230   /* If we have an INTEGER PRIMARY KEY, make sure the primary key
1231   ** of the new record does not previously exist.  Except, if this
1232   ** is an UPDATE and the primary key is not changing, that is OK.
1233   */
1234   if( rowidChng ){
1235     onError = pTab->keyConf;
1236     if( overrideError!=OE_Default ){
1237       onError = overrideError;
1238     }else if( onError==OE_Default ){
1239       onError = OE_Abort;
1240     }
1241 
1242     if( isUpdate ){
1243       j2 = sqlite3VdbeAddOp3(v, OP_Eq, regRowid, 0, rowidChng);
1244     }
1245     j3 = sqlite3VdbeAddOp3(v, OP_NotExists, baseCur, 0, regRowid);
1246     switch( onError ){
1247       default: {
1248         onError = OE_Abort;
1249         /* Fall thru into the next case */
1250       }
1251       case OE_Rollback:
1252       case OE_Abort:
1253       case OE_Fail: {
1254         sqlite3HaltConstraint(
1255           pParse, onError, "PRIMARY KEY must be unique", P4_STATIC);
1256         break;
1257       }
1258       case OE_Replace: {
1259         /* If there are DELETE triggers on this table and the
1260         ** recursive-triggers flag is set, call GenerateRowDelete() to
1261         ** remove the conflicting row from the the table. This will fire
1262         ** the triggers and remove both the table and index b-tree entries.
1263         **
1264         ** Otherwise, if there are no triggers or the recursive-triggers
1265         ** flag is not set, but the table has one or more indexes, call
1266         ** GenerateRowIndexDelete(). This removes the index b-tree entries
1267         ** only. The table b-tree entry will be replaced by the new entry
1268         ** when it is inserted.
1269         **
1270         ** If either GenerateRowDelete() or GenerateRowIndexDelete() is called,
1271         ** also invoke MultiWrite() to indicate that this VDBE may require
1272         ** statement rollback (if the statement is aborted after the delete
1273         ** takes place). Earlier versions called sqlite3MultiWrite() regardless,
1274         ** but being more selective here allows statements like:
1275         **
1276         **   REPLACE INTO t(rowid) VALUES($newrowid)
1277         **
1278         ** to run without a statement journal if there are no indexes on the
1279         ** table.
1280         */
1281         Trigger *pTrigger = 0;
1282         if( pParse->db->flags&SQLITE_RecTriggers ){
1283           pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
1284         }
1285         if( pTrigger || sqlite3FkRequired(pParse, pTab, 0, 0) ){
1286           sqlite3MultiWrite(pParse);
1287           sqlite3GenerateRowDelete(
1288               pParse, pTab, baseCur, regRowid, 0, pTrigger, OE_Replace
1289           );
1290         }else if( pTab->pIndex ){
1291           sqlite3MultiWrite(pParse);
1292           sqlite3GenerateRowIndexDelete(pParse, pTab, baseCur, 0);
1293         }
1294         seenReplace = 1;
1295         break;
1296       }
1297       case OE_Ignore: {
1298         assert( seenReplace==0 );
1299         sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
1300         break;
1301       }
1302     }
1303     sqlite3VdbeJumpHere(v, j3);
1304     if( isUpdate ){
1305       sqlite3VdbeJumpHere(v, j2);
1306     }
1307   }
1308 
1309   /* Test all UNIQUE constraints by creating entries for each UNIQUE
1310   ** index and making sure that duplicate entries do not already exist.
1311   ** Add the new records to the indices as we go.
1312   */
1313   for(iCur=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, iCur++){
1314     int regIdx;
1315     int regR;
1316 
1317     if( aRegIdx[iCur]==0 ) continue;  /* Skip unused indices */
1318 
1319     /* Create a key for accessing the index entry */
1320     regIdx = sqlite3GetTempRange(pParse, pIdx->nColumn+1);
1321     for(i=0; i<pIdx->nColumn; i++){
1322       int idx = pIdx->aiColumn[i];
1323       if( idx==pTab->iPKey ){
1324         sqlite3VdbeAddOp2(v, OP_SCopy, regRowid, regIdx+i);
1325       }else{
1326         sqlite3VdbeAddOp2(v, OP_SCopy, regData+idx, regIdx+i);
1327       }
1328     }
1329     sqlite3VdbeAddOp2(v, OP_SCopy, regRowid, regIdx+i);
1330     sqlite3VdbeAddOp3(v, OP_MakeRecord, regIdx, pIdx->nColumn+1, aRegIdx[iCur]);
1331     sqlite3VdbeChangeP4(v, -1, sqlite3IndexAffinityStr(v, pIdx), P4_TRANSIENT);
1332     sqlite3ExprCacheAffinityChange(pParse, regIdx, pIdx->nColumn+1);
1333 
1334     /* Find out what action to take in case there is an indexing conflict */
1335     onError = pIdx->onError;
1336     if( onError==OE_None ){
1337       sqlite3ReleaseTempRange(pParse, regIdx, pIdx->nColumn+1);
1338       continue;  /* pIdx is not a UNIQUE index */
1339     }
1340     if( overrideError!=OE_Default ){
1341       onError = overrideError;
1342     }else if( onError==OE_Default ){
1343       onError = OE_Abort;
1344     }
1345     if( seenReplace ){
1346       if( onError==OE_Ignore ) onError = OE_Replace;
1347       else if( onError==OE_Fail ) onError = OE_Abort;
1348     }
1349 
1350     /* Check to see if the new index entry will be unique */
1351     regR = sqlite3GetTempReg(pParse);
1352     sqlite3VdbeAddOp2(v, OP_SCopy, regOldRowid, regR);
1353     j3 = sqlite3VdbeAddOp4(v, OP_IsUnique, baseCur+iCur+1, 0,
1354                            regR, SQLITE_INT_TO_PTR(regIdx),
1355                            P4_INT32);
1356     sqlite3ReleaseTempRange(pParse, regIdx, pIdx->nColumn+1);
1357 
1358     /* Generate code that executes if the new index entry is not unique */
1359     assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
1360         || onError==OE_Ignore || onError==OE_Replace );
1361     switch( onError ){
1362       case OE_Rollback:
1363       case OE_Abort:
1364       case OE_Fail: {
1365         int j;
1366         StrAccum errMsg;
1367         const char *zSep;
1368         char *zErr;
1369 
1370         sqlite3StrAccumInit(&errMsg, 0, 0, 200);
1371         errMsg.db = pParse->db;
1372         zSep = pIdx->nColumn>1 ? "columns " : "column ";
1373         for(j=0; j<pIdx->nColumn; j++){
1374           char *zCol = pTab->aCol[pIdx->aiColumn[j]].zName;
1375           sqlite3StrAccumAppend(&errMsg, zSep, -1);
1376           zSep = ", ";
1377           sqlite3StrAccumAppend(&errMsg, zCol, -1);
1378         }
1379         sqlite3StrAccumAppend(&errMsg,
1380             pIdx->nColumn>1 ? " are not unique" : " is not unique", -1);
1381         zErr = sqlite3StrAccumFinish(&errMsg);
1382         sqlite3HaltConstraint(pParse, onError, zErr, 0);
1383         sqlite3DbFree(errMsg.db, zErr);
1384         break;
1385       }
1386       case OE_Ignore: {
1387         assert( seenReplace==0 );
1388         sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
1389         break;
1390       }
1391       default: {
1392         Trigger *pTrigger = 0;
1393         assert( onError==OE_Replace );
1394         sqlite3MultiWrite(pParse);
1395         if( pParse->db->flags&SQLITE_RecTriggers ){
1396           pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
1397         }
1398         sqlite3GenerateRowDelete(
1399             pParse, pTab, baseCur, regR, 0, pTrigger, OE_Replace
1400         );
1401         seenReplace = 1;
1402         break;
1403       }
1404     }
1405     sqlite3VdbeJumpHere(v, j3);
1406     sqlite3ReleaseTempReg(pParse, regR);
1407   }
1408 
1409   if( pbMayReplace ){
1410     *pbMayReplace = seenReplace;
1411   }
1412 }
1413 
1414 /*
1415 ** This routine generates code to finish the INSERT or UPDATE operation
1416 ** that was started by a prior call to sqlite3GenerateConstraintChecks.
1417 ** A consecutive range of registers starting at regRowid contains the
1418 ** rowid and the content to be inserted.
1419 **
1420 ** The arguments to this routine should be the same as the first six
1421 ** arguments to sqlite3GenerateConstraintChecks.
1422 */
sqlite3CompleteInsertion(Parse * pParse,Table * pTab,int baseCur,int regRowid,int * aRegIdx,int isUpdate,int appendBias,int useSeekResult)1423 void sqlite3CompleteInsertion(
1424   Parse *pParse,      /* The parser context */
1425   Table *pTab,        /* the table into which we are inserting */
1426   int baseCur,        /* Index of a read/write cursor pointing at pTab */
1427   int regRowid,       /* Range of content */
1428   int *aRegIdx,       /* Register used by each index.  0 for unused indices */
1429   int isUpdate,       /* True for UPDATE, False for INSERT */
1430   int appendBias,     /* True if this is likely to be an append */
1431   int useSeekResult   /* True to set the USESEEKRESULT flag on OP_[Idx]Insert */
1432 ){
1433   int i;
1434   Vdbe *v;
1435   int nIdx;
1436   Index *pIdx;
1437   u8 pik_flags;
1438   int regData;
1439   int regRec;
1440 
1441   v = sqlite3GetVdbe(pParse);
1442   assert( v!=0 );
1443   assert( pTab->pSelect==0 );  /* This table is not a VIEW */
1444   for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){}
1445   for(i=nIdx-1; i>=0; i--){
1446     if( aRegIdx[i]==0 ) continue;
1447     sqlite3VdbeAddOp2(v, OP_IdxInsert, baseCur+i+1, aRegIdx[i]);
1448     if( useSeekResult ){
1449       sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
1450     }
1451   }
1452   regData = regRowid + 1;
1453   regRec = sqlite3GetTempReg(pParse);
1454   sqlite3VdbeAddOp3(v, OP_MakeRecord, regData, pTab->nCol, regRec);
1455   sqlite3TableAffinityStr(v, pTab);
1456   sqlite3ExprCacheAffinityChange(pParse, regData, pTab->nCol);
1457   if( pParse->nested ){
1458     pik_flags = 0;
1459   }else{
1460     pik_flags = OPFLAG_NCHANGE;
1461     pik_flags |= (isUpdate?OPFLAG_ISUPDATE:OPFLAG_LASTROWID);
1462   }
1463   if( appendBias ){
1464     pik_flags |= OPFLAG_APPEND;
1465   }
1466   if( useSeekResult ){
1467     pik_flags |= OPFLAG_USESEEKRESULT;
1468   }
1469   sqlite3VdbeAddOp3(v, OP_Insert, baseCur, regRec, regRowid);
1470   if( !pParse->nested ){
1471     sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_TRANSIENT);
1472   }
1473   sqlite3VdbeChangeP5(v, pik_flags);
1474 }
1475 
1476 /*
1477 ** Generate code that will open cursors for a table and for all
1478 ** indices of that table.  The "baseCur" parameter is the cursor number used
1479 ** for the table.  Indices are opened on subsequent cursors.
1480 **
1481 ** Return the number of indices on the table.
1482 */
sqlite3OpenTableAndIndices(Parse * pParse,Table * pTab,int baseCur,int op)1483 int sqlite3OpenTableAndIndices(
1484   Parse *pParse,   /* Parsing context */
1485   Table *pTab,     /* Table to be opened */
1486   int baseCur,     /* Cursor number assigned to the table */
1487   int op           /* OP_OpenRead or OP_OpenWrite */
1488 ){
1489   int i;
1490   int iDb;
1491   Index *pIdx;
1492   Vdbe *v;
1493 
1494   if( IsVirtual(pTab) ) return 0;
1495   iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
1496   v = sqlite3GetVdbe(pParse);
1497   assert( v!=0 );
1498   sqlite3OpenTable(pParse, baseCur, iDb, pTab, op);
1499   for(i=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
1500     KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
1501     assert( pIdx->pSchema==pTab->pSchema );
1502     sqlite3VdbeAddOp4(v, op, i+baseCur, pIdx->tnum, iDb,
1503                       (char*)pKey, P4_KEYINFO_HANDOFF);
1504     VdbeComment((v, "%s", pIdx->zName));
1505   }
1506   if( pParse->nTab<baseCur+i ){
1507     pParse->nTab = baseCur+i;
1508   }
1509   return i-1;
1510 }
1511 
1512 
1513 #ifdef SQLITE_TEST
1514 /*
1515 ** The following global variable is incremented whenever the
1516 ** transfer optimization is used.  This is used for testing
1517 ** purposes only - to make sure the transfer optimization really
1518 ** is happening when it is suppose to.
1519 */
1520 int sqlite3_xferopt_count;
1521 #endif /* SQLITE_TEST */
1522 
1523 
1524 #ifndef SQLITE_OMIT_XFER_OPT
1525 /*
1526 ** Check to collation names to see if they are compatible.
1527 */
xferCompatibleCollation(const char * z1,const char * z2)1528 static int xferCompatibleCollation(const char *z1, const char *z2){
1529   if( z1==0 ){
1530     return z2==0;
1531   }
1532   if( z2==0 ){
1533     return 0;
1534   }
1535   return sqlite3StrICmp(z1, z2)==0;
1536 }
1537 
1538 
1539 /*
1540 ** Check to see if index pSrc is compatible as a source of data
1541 ** for index pDest in an insert transfer optimization.  The rules
1542 ** for a compatible index:
1543 **
1544 **    *   The index is over the same set of columns
1545 **    *   The same DESC and ASC markings occurs on all columns
1546 **    *   The same onError processing (OE_Abort, OE_Ignore, etc)
1547 **    *   The same collating sequence on each column
1548 */
xferCompatibleIndex(Index * pDest,Index * pSrc)1549 static int xferCompatibleIndex(Index *pDest, Index *pSrc){
1550   int i;
1551   assert( pDest && pSrc );
1552   assert( pDest->pTable!=pSrc->pTable );
1553   if( pDest->nColumn!=pSrc->nColumn ){
1554     return 0;   /* Different number of columns */
1555   }
1556   if( pDest->onError!=pSrc->onError ){
1557     return 0;   /* Different conflict resolution strategies */
1558   }
1559   for(i=0; i<pSrc->nColumn; i++){
1560     if( pSrc->aiColumn[i]!=pDest->aiColumn[i] ){
1561       return 0;   /* Different columns indexed */
1562     }
1563     if( pSrc->aSortOrder[i]!=pDest->aSortOrder[i] ){
1564       return 0;   /* Different sort orders */
1565     }
1566     if( !xferCompatibleCollation(pSrc->azColl[i],pDest->azColl[i]) ){
1567       return 0;   /* Different collating sequences */
1568     }
1569   }
1570 
1571   /* If no test above fails then the indices must be compatible */
1572   return 1;
1573 }
1574 
1575 /*
1576 ** Attempt the transfer optimization on INSERTs of the form
1577 **
1578 **     INSERT INTO tab1 SELECT * FROM tab2;
1579 **
1580 ** This optimization is only attempted if
1581 **
1582 **    (1)  tab1 and tab2 have identical schemas including all the
1583 **         same indices and constraints
1584 **
1585 **    (2)  tab1 and tab2 are different tables
1586 **
1587 **    (3)  There must be no triggers on tab1
1588 **
1589 **    (4)  The result set of the SELECT statement is "*"
1590 **
1591 **    (5)  The SELECT statement has no WHERE, HAVING, ORDER BY, GROUP BY,
1592 **         or LIMIT clause.
1593 **
1594 **    (6)  The SELECT statement is a simple (not a compound) select that
1595 **         contains only tab2 in its FROM clause
1596 **
1597 ** This method for implementing the INSERT transfers raw records from
1598 ** tab2 over to tab1.  The columns are not decoded.  Raw records from
1599 ** the indices of tab2 are transfered to tab1 as well.  In so doing,
1600 ** the resulting tab1 has much less fragmentation.
1601 **
1602 ** This routine returns TRUE if the optimization is attempted.  If any
1603 ** of the conditions above fail so that the optimization should not
1604 ** be attempted, then this routine returns FALSE.
1605 */
xferOptimization(Parse * pParse,Table * pDest,Select * pSelect,int onError,int iDbDest)1606 static int xferOptimization(
1607   Parse *pParse,        /* Parser context */
1608   Table *pDest,         /* The table we are inserting into */
1609   Select *pSelect,      /* A SELECT statement to use as the data source */
1610   int onError,          /* How to handle constraint errors */
1611   int iDbDest           /* The database of pDest */
1612 ){
1613   ExprList *pEList;                /* The result set of the SELECT */
1614   Table *pSrc;                     /* The table in the FROM clause of SELECT */
1615   Index *pSrcIdx, *pDestIdx;       /* Source and destination indices */
1616   struct SrcList_item *pItem;      /* An element of pSelect->pSrc */
1617   int i;                           /* Loop counter */
1618   int iDbSrc;                      /* The database of pSrc */
1619   int iSrc, iDest;                 /* Cursors from source and destination */
1620   int addr1, addr2;                /* Loop addresses */
1621   int emptyDestTest;               /* Address of test for empty pDest */
1622   int emptySrcTest;                /* Address of test for empty pSrc */
1623   Vdbe *v;                         /* The VDBE we are building */
1624   KeyInfo *pKey;                   /* Key information for an index */
1625   int regAutoinc;                  /* Memory register used by AUTOINC */
1626   int destHasUniqueIdx = 0;        /* True if pDest has a UNIQUE index */
1627   int regData, regRowid;           /* Registers holding data and rowid */
1628 
1629   if( pSelect==0 ){
1630     return 0;   /* Must be of the form  INSERT INTO ... SELECT ... */
1631   }
1632   if( sqlite3TriggerList(pParse, pDest) ){
1633     return 0;   /* tab1 must not have triggers */
1634   }
1635 #ifndef SQLITE_OMIT_VIRTUALTABLE
1636   if( pDest->tabFlags & TF_Virtual ){
1637     return 0;   /* tab1 must not be a virtual table */
1638   }
1639 #endif
1640   if( onError==OE_Default ){
1641     onError = OE_Abort;
1642   }
1643   if( onError!=OE_Abort && onError!=OE_Rollback ){
1644     return 0;   /* Cannot do OR REPLACE or OR IGNORE or OR FAIL */
1645   }
1646   assert(pSelect->pSrc);   /* allocated even if there is no FROM clause */
1647   if( pSelect->pSrc->nSrc!=1 ){
1648     return 0;   /* FROM clause must have exactly one term */
1649   }
1650   if( pSelect->pSrc->a[0].pSelect ){
1651     return 0;   /* FROM clause cannot contain a subquery */
1652   }
1653   if( pSelect->pWhere ){
1654     return 0;   /* SELECT may not have a WHERE clause */
1655   }
1656   if( pSelect->pOrderBy ){
1657     return 0;   /* SELECT may not have an ORDER BY clause */
1658   }
1659   /* Do not need to test for a HAVING clause.  If HAVING is present but
1660   ** there is no ORDER BY, we will get an error. */
1661   if( pSelect->pGroupBy ){
1662     return 0;   /* SELECT may not have a GROUP BY clause */
1663   }
1664   if( pSelect->pLimit ){
1665     return 0;   /* SELECT may not have a LIMIT clause */
1666   }
1667   assert( pSelect->pOffset==0 );  /* Must be so if pLimit==0 */
1668   if( pSelect->pPrior ){
1669     return 0;   /* SELECT may not be a compound query */
1670   }
1671   if( pSelect->selFlags & SF_Distinct ){
1672     return 0;   /* SELECT may not be DISTINCT */
1673   }
1674   pEList = pSelect->pEList;
1675   assert( pEList!=0 );
1676   if( pEList->nExpr!=1 ){
1677     return 0;   /* The result set must have exactly one column */
1678   }
1679   assert( pEList->a[0].pExpr );
1680   if( pEList->a[0].pExpr->op!=TK_ALL ){
1681     return 0;   /* The result set must be the special operator "*" */
1682   }
1683 
1684   /* At this point we have established that the statement is of the
1685   ** correct syntactic form to participate in this optimization.  Now
1686   ** we have to check the semantics.
1687   */
1688   pItem = pSelect->pSrc->a;
1689   pSrc = sqlite3LocateTable(pParse, 0, pItem->zName, pItem->zDatabase);
1690   if( pSrc==0 ){
1691     return 0;   /* FROM clause does not contain a real table */
1692   }
1693   if( pSrc==pDest ){
1694     return 0;   /* tab1 and tab2 may not be the same table */
1695   }
1696 #ifndef SQLITE_OMIT_VIRTUALTABLE
1697   if( pSrc->tabFlags & TF_Virtual ){
1698     return 0;   /* tab2 must not be a virtual table */
1699   }
1700 #endif
1701   if( pSrc->pSelect ){
1702     return 0;   /* tab2 may not be a view */
1703   }
1704   if( pDest->nCol!=pSrc->nCol ){
1705     return 0;   /* Number of columns must be the same in tab1 and tab2 */
1706   }
1707   if( pDest->iPKey!=pSrc->iPKey ){
1708     return 0;   /* Both tables must have the same INTEGER PRIMARY KEY */
1709   }
1710   for(i=0; i<pDest->nCol; i++){
1711     if( pDest->aCol[i].affinity!=pSrc->aCol[i].affinity ){
1712       return 0;    /* Affinity must be the same on all columns */
1713     }
1714     if( !xferCompatibleCollation(pDest->aCol[i].zColl, pSrc->aCol[i].zColl) ){
1715       return 0;    /* Collating sequence must be the same on all columns */
1716     }
1717     if( pDest->aCol[i].notNull && !pSrc->aCol[i].notNull ){
1718       return 0;    /* tab2 must be NOT NULL if tab1 is */
1719     }
1720   }
1721   for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
1722     if( pDestIdx->onError!=OE_None ){
1723       destHasUniqueIdx = 1;
1724     }
1725     for(pSrcIdx=pSrc->pIndex; pSrcIdx; pSrcIdx=pSrcIdx->pNext){
1726       if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
1727     }
1728     if( pSrcIdx==0 ){
1729       return 0;    /* pDestIdx has no corresponding index in pSrc */
1730     }
1731   }
1732 #ifndef SQLITE_OMIT_CHECK
1733   if( pDest->pCheck && sqlite3ExprCompare(pSrc->pCheck, pDest->pCheck) ){
1734     return 0;   /* Tables have different CHECK constraints.  Ticket #2252 */
1735   }
1736 #endif
1737 
1738   /* If we get this far, it means either:
1739   **
1740   **    *   We can always do the transfer if the table contains an
1741   **        an integer primary key
1742   **
1743   **    *   We can conditionally do the transfer if the destination
1744   **        table is empty.
1745   */
1746 #ifdef SQLITE_TEST
1747   sqlite3_xferopt_count++;
1748 #endif
1749   iDbSrc = sqlite3SchemaToIndex(pParse->db, pSrc->pSchema);
1750   v = sqlite3GetVdbe(pParse);
1751   sqlite3CodeVerifySchema(pParse, iDbSrc);
1752   iSrc = pParse->nTab++;
1753   iDest = pParse->nTab++;
1754   regAutoinc = autoIncBegin(pParse, iDbDest, pDest);
1755   sqlite3OpenTable(pParse, iDest, iDbDest, pDest, OP_OpenWrite);
1756   if( (pDest->iPKey<0 && pDest->pIndex!=0) || destHasUniqueIdx ){
1757     /* If tables do not have an INTEGER PRIMARY KEY and there
1758     ** are indices to be copied and the destination is not empty,
1759     ** we have to disallow the transfer optimization because the
1760     ** the rowids might change which will mess up indexing.
1761     **
1762     ** Or if the destination has a UNIQUE index and is not empty,
1763     ** we also disallow the transfer optimization because we cannot
1764     ** insure that all entries in the union of DEST and SRC will be
1765     ** unique.
1766     */
1767     addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iDest, 0);
1768     emptyDestTest = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
1769     sqlite3VdbeJumpHere(v, addr1);
1770   }else{
1771     emptyDestTest = 0;
1772   }
1773   sqlite3OpenTable(pParse, iSrc, iDbSrc, pSrc, OP_OpenRead);
1774   emptySrcTest = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0);
1775   regData = sqlite3GetTempReg(pParse);
1776   regRowid = sqlite3GetTempReg(pParse);
1777   if( pDest->iPKey>=0 ){
1778     addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
1779     addr2 = sqlite3VdbeAddOp3(v, OP_NotExists, iDest, 0, regRowid);
1780     sqlite3HaltConstraint(
1781         pParse, onError, "PRIMARY KEY must be unique", P4_STATIC);
1782     sqlite3VdbeJumpHere(v, addr2);
1783     autoIncStep(pParse, regAutoinc, regRowid);
1784   }else if( pDest->pIndex==0 ){
1785     addr1 = sqlite3VdbeAddOp2(v, OP_NewRowid, iDest, regRowid);
1786   }else{
1787     addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
1788     assert( (pDest->tabFlags & TF_Autoincrement)==0 );
1789   }
1790   sqlite3VdbeAddOp2(v, OP_RowData, iSrc, regData);
1791   sqlite3VdbeAddOp3(v, OP_Insert, iDest, regData, regRowid);
1792   sqlite3VdbeChangeP5(v, OPFLAG_NCHANGE|OPFLAG_LASTROWID|OPFLAG_APPEND);
1793   sqlite3VdbeChangeP4(v, -1, pDest->zName, 0);
1794   sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1);
1795   for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
1796     for(pSrcIdx=pSrc->pIndex; ALWAYS(pSrcIdx); pSrcIdx=pSrcIdx->pNext){
1797       if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
1798     }
1799     assert( pSrcIdx );
1800     sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
1801     sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
1802     pKey = sqlite3IndexKeyinfo(pParse, pSrcIdx);
1803     sqlite3VdbeAddOp4(v, OP_OpenRead, iSrc, pSrcIdx->tnum, iDbSrc,
1804                       (char*)pKey, P4_KEYINFO_HANDOFF);
1805     VdbeComment((v, "%s", pSrcIdx->zName));
1806     pKey = sqlite3IndexKeyinfo(pParse, pDestIdx);
1807     sqlite3VdbeAddOp4(v, OP_OpenWrite, iDest, pDestIdx->tnum, iDbDest,
1808                       (char*)pKey, P4_KEYINFO_HANDOFF);
1809     VdbeComment((v, "%s", pDestIdx->zName));
1810     addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0);
1811     sqlite3VdbeAddOp2(v, OP_RowKey, iSrc, regData);
1812     sqlite3VdbeAddOp3(v, OP_IdxInsert, iDest, regData, 1);
1813     sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1+1);
1814     sqlite3VdbeJumpHere(v, addr1);
1815   }
1816   sqlite3VdbeJumpHere(v, emptySrcTest);
1817   sqlite3ReleaseTempReg(pParse, regRowid);
1818   sqlite3ReleaseTempReg(pParse, regData);
1819   sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
1820   sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
1821   if( emptyDestTest ){
1822     sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_OK, 0);
1823     sqlite3VdbeJumpHere(v, emptyDestTest);
1824     sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
1825     return 0;
1826   }else{
1827     return 1;
1828   }
1829 }
1830 #endif /* SQLITE_OMIT_XFER_OPT */
1831