xref: /sqlite-3.40.0/src/delete.c (revision 5d00d0a8)
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 ** in order to generate code for DELETE FROM statements.
14 **
15 ** $Id: delete.c,v 1.207 2009/08/08 18:01:08 drh Exp $
16 */
17 #include "sqliteInt.h"
18 
19 /*
20 ** Look up every table that is named in pSrc.  If any table is not found,
21 ** add an error message to pParse->zErrMsg and return NULL.  If all tables
22 ** are found, return a pointer to the last table.
23 */
24 Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc){
25   struct SrcList_item *pItem = pSrc->a;
26   Table *pTab;
27   assert( pItem && pSrc->nSrc==1 );
28   pTab = sqlite3LocateTable(pParse, 0, pItem->zName, pItem->zDatabase);
29   sqlite3DeleteTable(pItem->pTab);
30   pItem->pTab = pTab;
31   if( pTab ){
32     pTab->nRef++;
33   }
34   if( sqlite3IndexedByLookup(pParse, pItem) ){
35     pTab = 0;
36   }
37   return pTab;
38 }
39 
40 /*
41 ** Check to make sure the given table is writable.  If it is not
42 ** writable, generate an error message and return 1.  If it is
43 ** writable return 0;
44 */
45 int sqlite3IsReadOnly(Parse *pParse, Table *pTab, int viewOk){
46   /* A table is not writable under the following circumstances:
47   **
48   **   1) It is a virtual table and no implementation of the xUpdate method
49   **      has been provided, or
50   **   2) It is a system table (i.e. sqlite_master), this call is not
51   **      part of a nested parse and writable_schema pragma has not
52   **      been specified.
53   **
54   ** In either case leave an error message in pParse and return non-zero.
55   */
56   if( ( IsVirtual(pTab)
57      && sqlite3GetVTable(pParse->db, pTab)->pMod->pModule->xUpdate==0 )
58    || ( (pTab->tabFlags & TF_Readonly)!=0
59      && (pParse->db->flags & SQLITE_WriteSchema)==0
60      && pParse->nested==0 )
61   ){
62     sqlite3ErrorMsg(pParse, "table %s may not be modified", pTab->zName);
63     return 1;
64   }
65 
66 #ifndef SQLITE_OMIT_VIEW
67   if( !viewOk && pTab->pSelect ){
68     sqlite3ErrorMsg(pParse,"cannot modify %s because it is a view",pTab->zName);
69     return 1;
70   }
71 #endif
72   return 0;
73 }
74 
75 
76 #if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
77 /*
78 ** Evaluate a view and store its result in an ephemeral table.  The
79 ** pWhere argument is an optional WHERE clause that restricts the
80 ** set of rows in the view that are to be added to the ephemeral table.
81 */
82 void sqlite3MaterializeView(
83   Parse *pParse,       /* Parsing context */
84   Table *pView,        /* View definition */
85   Expr *pWhere,        /* Optional WHERE clause to be added */
86   int iCur             /* Cursor number for ephemerial table */
87 ){
88   SelectDest dest;
89   Select *pDup;
90   sqlite3 *db = pParse->db;
91 
92   pDup = sqlite3SelectDup(db, pView->pSelect, 0);
93   if( pWhere ){
94     SrcList *pFrom;
95 
96     pWhere = sqlite3ExprDup(db, pWhere, 0);
97     pFrom = sqlite3SrcListAppend(db, 0, 0, 0);
98     if( pFrom ){
99       assert( pFrom->nSrc==1 );
100       pFrom->a[0].zAlias = sqlite3DbStrDup(db, pView->zName);
101       pFrom->a[0].pSelect = pDup;
102       assert( pFrom->a[0].pOn==0 );
103       assert( pFrom->a[0].pUsing==0 );
104     }else{
105       sqlite3SelectDelete(db, pDup);
106     }
107     pDup = sqlite3SelectNew(pParse, 0, pFrom, pWhere, 0, 0, 0, 0, 0, 0);
108   }
109   sqlite3SelectDestInit(&dest, SRT_EphemTab, iCur);
110   sqlite3Select(pParse, pDup, &dest);
111   sqlite3SelectDelete(db, pDup);
112 }
113 #endif /* !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) */
114 
115 #if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)
116 /*
117 ** Generate an expression tree to implement the WHERE, ORDER BY,
118 ** and LIMIT/OFFSET portion of DELETE and UPDATE statements.
119 **
120 **     DELETE FROM table_wxyz WHERE a<5 ORDER BY a LIMIT 1;
121 **                            \__________________________/
122 **                               pLimitWhere (pInClause)
123 */
124 Expr *sqlite3LimitWhere(
125   Parse *pParse,               /* The parser context */
126   SrcList *pSrc,               /* the FROM clause -- which tables to scan */
127   Expr *pWhere,                /* The WHERE clause.  May be null */
128   ExprList *pOrderBy,          /* The ORDER BY clause.  May be null */
129   Expr *pLimit,                /* The LIMIT clause.  May be null */
130   Expr *pOffset,               /* The OFFSET clause.  May be null */
131   char *zStmtType              /* Either DELETE or UPDATE.  For error messages. */
132 ){
133   Expr *pWhereRowid = NULL;    /* WHERE rowid .. */
134   Expr *pInClause = NULL;      /* WHERE rowid IN ( select ) */
135   Expr *pSelectRowid = NULL;   /* SELECT rowid ... */
136   ExprList *pEList = NULL;     /* Expression list contaning only pSelectRowid */
137   SrcList *pSelectSrc = NULL;  /* SELECT rowid FROM x ... (dup of pSrc) */
138   Select *pSelect = NULL;      /* Complete SELECT tree */
139 
140   /* Check that there isn't an ORDER BY without a LIMIT clause.
141   */
142   if( pOrderBy && (pLimit == 0) ) {
143     sqlite3ErrorMsg(pParse, "ORDER BY without LIMIT on %s", zStmtType);
144     pParse->parseError = 1;
145     goto limit_where_cleanup_2;
146   }
147 
148   /* We only need to generate a select expression if there
149   ** is a limit/offset term to enforce.
150   */
151   if( pLimit == 0 ) {
152     /* if pLimit is null, pOffset will always be null as well. */
153     assert( pOffset == 0 );
154     return pWhere;
155   }
156 
157   /* Generate a select expression tree to enforce the limit/offset
158   ** term for the DELETE or UPDATE statement.  For example:
159   **   DELETE FROM table_a WHERE col1=1 ORDER BY col2 LIMIT 1 OFFSET 1
160   ** becomes:
161   **   DELETE FROM table_a WHERE rowid IN (
162   **     SELECT rowid FROM table_a WHERE col1=1 ORDER BY col2 LIMIT 1 OFFSET 1
163   **   );
164   */
165 
166   pSelectRowid = sqlite3PExpr(pParse, TK_ROW, 0, 0, 0);
167   if( pSelectRowid == 0 ) goto limit_where_cleanup_2;
168   pEList = sqlite3ExprListAppend(pParse, 0, pSelectRowid);
169   if( pEList == 0 ) goto limit_where_cleanup_2;
170 
171   /* duplicate the FROM clause as it is needed by both the DELETE/UPDATE tree
172   ** and the SELECT subtree. */
173   pSelectSrc = sqlite3SrcListDup(pParse->db, pSrc, 0);
174   if( pSelectSrc == 0 ) {
175     sqlite3ExprListDelete(pParse->db, pEList);
176     goto limit_where_cleanup_2;
177   }
178 
179   /* generate the SELECT expression tree. */
180   pSelect = sqlite3SelectNew(pParse,pEList,pSelectSrc,pWhere,0,0,
181                              pOrderBy,0,pLimit,pOffset);
182   if( pSelect == 0 ) return 0;
183 
184   /* now generate the new WHERE rowid IN clause for the DELETE/UDPATE */
185   pWhereRowid = sqlite3PExpr(pParse, TK_ROW, 0, 0, 0);
186   if( pWhereRowid == 0 ) goto limit_where_cleanup_1;
187   pInClause = sqlite3PExpr(pParse, TK_IN, pWhereRowid, 0, 0);
188   if( pInClause == 0 ) goto limit_where_cleanup_1;
189 
190   pInClause->x.pSelect = pSelect;
191   pInClause->flags |= EP_xIsSelect;
192   sqlite3ExprSetHeight(pParse, pInClause);
193   return pInClause;
194 
195   /* something went wrong. clean up anything allocated. */
196 limit_where_cleanup_1:
197   sqlite3SelectDelete(pParse->db, pSelect);
198   return 0;
199 
200 limit_where_cleanup_2:
201   sqlite3ExprDelete(pParse->db, pWhere);
202   sqlite3ExprListDelete(pParse->db, pOrderBy);
203   sqlite3ExprDelete(pParse->db, pLimit);
204   sqlite3ExprDelete(pParse->db, pOffset);
205   return 0;
206 }
207 #endif /* defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY) */
208 
209 /*
210 ** Generate code for a DELETE FROM statement.
211 **
212 **     DELETE FROM table_wxyz WHERE a<5 AND b NOT NULL;
213 **                 \________/       \________________/
214 **                  pTabList              pWhere
215 */
216 void sqlite3DeleteFrom(
217   Parse *pParse,         /* The parser context */
218   SrcList *pTabList,     /* The table from which we should delete things */
219   Expr *pWhere           /* The WHERE clause.  May be null */
220 ){
221   Vdbe *v;               /* The virtual database engine */
222   Table *pTab;           /* The table from which records will be deleted */
223   const char *zDb;       /* Name of database holding pTab */
224   int end, addr = 0;     /* A couple addresses of generated code */
225   int i;                 /* Loop counter */
226   WhereInfo *pWInfo;     /* Information about the WHERE clause */
227   Index *pIdx;           /* For looping over indices of the table */
228   int iCur;              /* VDBE Cursor number for pTab */
229   sqlite3 *db;           /* Main database structure */
230   AuthContext sContext;  /* Authorization context */
231   int oldIdx = -1;       /* Cursor for the OLD table of AFTER triggers */
232   NameContext sNC;       /* Name context to resolve expressions in */
233   int iDb;               /* Database number */
234   int memCnt = -1;       /* Memory cell used for change counting */
235   int rcauth;            /* Value returned by authorization callback */
236 
237 #ifndef SQLITE_OMIT_TRIGGER
238   int isView;                  /* True if attempting to delete from a view */
239   Trigger *pTrigger;           /* List of table triggers, if required */
240 #endif
241   int iBeginAfterTrigger = 0;  /* Address of after trigger program */
242   int iEndAfterTrigger = 0;    /* Exit of after trigger program */
243   int iBeginBeforeTrigger = 0; /* Address of before trigger program */
244   int iEndBeforeTrigger = 0;   /* Exit of before trigger program */
245   u32 old_col_mask = 0;        /* Mask of OLD.* columns in use */
246 
247   memset(&sContext, 0, sizeof(sContext));
248   db = pParse->db;
249   if( pParse->nErr || db->mallocFailed ){
250     goto delete_from_cleanup;
251   }
252   assert( pTabList->nSrc==1 );
253 
254   /* Locate the table which we want to delete.  This table has to be
255   ** put in an SrcList structure because some of the subroutines we
256   ** will be calling are designed to work with multiple tables and expect
257   ** an SrcList* parameter instead of just a Table* parameter.
258   */
259   pTab = sqlite3SrcListLookup(pParse, pTabList);
260   if( pTab==0 )  goto delete_from_cleanup;
261 
262   /* Figure out if we have any triggers and if the table being
263   ** deleted from is a view
264   */
265 #ifndef SQLITE_OMIT_TRIGGER
266   pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
267   isView = pTab->pSelect!=0;
268 #else
269 # define pTrigger 0
270 # define isView 0
271 #endif
272 #ifdef SQLITE_OMIT_VIEW
273 # undef isView
274 # define isView 0
275 #endif
276 
277   /* If pTab is really a view, make sure it has been initialized.
278   */
279   if( sqlite3ViewGetColumnNames(pParse, pTab) ){
280     goto delete_from_cleanup;
281   }
282 
283   if( sqlite3IsReadOnly(pParse, pTab, (pTrigger?1:0)) ){
284     goto delete_from_cleanup;
285   }
286   iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
287   assert( iDb<db->nDb );
288   zDb = db->aDb[iDb].zName;
289   rcauth = sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0, zDb);
290   assert( rcauth==SQLITE_OK || rcauth==SQLITE_DENY || rcauth==SQLITE_IGNORE );
291   if( rcauth==SQLITE_DENY ){
292     goto delete_from_cleanup;
293   }
294   assert(!isView || pTrigger);
295 
296   /* Allocate a cursor used to store the old.* data for a trigger.
297   */
298   if( pTrigger ){
299     oldIdx = pParse->nTab++;
300   }
301 
302   /* Assign  cursor number to the table and all its indices.
303   */
304   assert( pTabList->nSrc==1 );
305   iCur = pTabList->a[0].iCursor = pParse->nTab++;
306   for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
307     pParse->nTab++;
308   }
309 
310   /* Start the view context
311   */
312   if( isView ){
313     sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
314   }
315 
316   /* Begin generating code.
317   */
318   v = sqlite3GetVdbe(pParse);
319   if( v==0 ){
320     goto delete_from_cleanup;
321   }
322   if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
323   sqlite3BeginWriteOperation(pParse, (pTrigger?1:0), iDb);
324 
325   if( pTrigger ){
326     int orconf = ((pParse->trigStack)?pParse->trigStack->orconf:OE_Default);
327     int iGoto = sqlite3VdbeAddOp0(v, OP_Goto);
328     addr = sqlite3VdbeMakeLabel(v);
329 
330     iBeginBeforeTrigger = sqlite3VdbeCurrentAddr(v);
331     (void)sqlite3CodeRowTrigger(pParse, pTrigger, TK_DELETE, 0,
332         TRIGGER_BEFORE, pTab, -1, oldIdx, orconf, addr, &old_col_mask, 0);
333     iEndBeforeTrigger = sqlite3VdbeAddOp0(v, OP_Goto);
334 
335     iBeginAfterTrigger = sqlite3VdbeCurrentAddr(v);
336     (void)sqlite3CodeRowTrigger(pParse, pTrigger, TK_DELETE, 0,
337         TRIGGER_AFTER, pTab, -1, oldIdx, orconf, addr, &old_col_mask, 0);
338     iEndAfterTrigger = sqlite3VdbeAddOp0(v, OP_Goto);
339 
340     sqlite3VdbeJumpHere(v, iGoto);
341   }
342 
343   /* If we are trying to delete from a view, realize that view into
344   ** a ephemeral table.
345   */
346 #if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
347   if( isView ){
348     sqlite3MaterializeView(pParse, pTab, pWhere, iCur);
349   }
350 #endif
351 
352   /* Resolve the column names in the WHERE clause.
353   */
354   memset(&sNC, 0, sizeof(sNC));
355   sNC.pParse = pParse;
356   sNC.pSrcList = pTabList;
357   if( sqlite3ResolveExprNames(&sNC, pWhere) ){
358     goto delete_from_cleanup;
359   }
360 
361   /* Initialize the counter of the number of rows deleted, if
362   ** we are counting rows.
363   */
364   if( db->flags & SQLITE_CountRows ){
365     memCnt = ++pParse->nMem;
366     sqlite3VdbeAddOp2(v, OP_Integer, 0, memCnt);
367   }
368 
369 #ifndef SQLITE_OMIT_TRUNCATE_OPTIMIZATION
370   /* Special case: A DELETE without a WHERE clause deletes everything.
371   ** It is easier just to erase the whole table.  Note, however, that
372   ** this means that the row change count will be incorrect.
373   */
374   if( rcauth==SQLITE_OK && pWhere==0 && !pTrigger && !IsVirtual(pTab) ){
375     assert( !isView );
376     sqlite3VdbeAddOp4(v, OP_Clear, pTab->tnum, iDb, memCnt,
377                       pTab->zName, P4_STATIC);
378     for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
379       assert( pIdx->pSchema==pTab->pSchema );
380       sqlite3VdbeAddOp2(v, OP_Clear, pIdx->tnum, iDb);
381     }
382   }else
383 #endif /* SQLITE_OMIT_TRUNCATE_OPTIMIZATION */
384   /* The usual case: There is a WHERE clause so we have to scan through
385   ** the table and pick which records to delete.
386   */
387   {
388     int iRowid = ++pParse->nMem;    /* Used for storing rowid values. */
389     int iRowSet = ++pParse->nMem;   /* Register for rowset of rows to delete */
390     int regRowid;                   /* Actual register containing rowids */
391 
392     /* Collect rowids of every row to be deleted.
393     */
394     sqlite3VdbeAddOp2(v, OP_Null, 0, iRowSet);
395     pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere,0,WHERE_DUPLICATES_OK);
396     if( pWInfo==0 ) goto delete_from_cleanup;
397     regRowid = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iCur, iRowid, 0);
398     sqlite3VdbeAddOp2(v, OP_RowSetAdd, iRowSet, regRowid);
399     if( db->flags & SQLITE_CountRows ){
400       sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
401     }
402     sqlite3WhereEnd(pWInfo);
403 
404     /* Open the pseudo-table used to store OLD if there are triggers.
405     */
406     if( pTrigger ){
407       sqlite3VdbeAddOp3(v, OP_OpenPseudo, oldIdx, 0, pTab->nCol);
408     }
409 
410     /* Delete every item whose key was written to the list during the
411     ** database scan.  We have to delete items after the scan is complete
412     ** because deleting an item can change the scan order.
413     */
414     end = sqlite3VdbeMakeLabel(v);
415 
416     if( !isView ){
417       /* Open cursors for the table we are deleting from and
418       ** all its indices.
419       */
420       sqlite3OpenTableAndIndices(pParse, pTab, iCur, OP_OpenWrite);
421     }
422 
423     /* This is the beginning of the delete loop. If a trigger encounters
424     ** an IGNORE constraint, it jumps back to here.
425     */
426     if( pTrigger ){
427       sqlite3VdbeResolveLabel(v, addr);
428     }
429     addr = sqlite3VdbeAddOp3(v, OP_RowSetRead, iRowSet, end, iRowid);
430 
431     if( pTrigger ){
432       int iData = ++pParse->nMem;   /* For storing row data of OLD table */
433 
434       /* If the record is no longer present in the table, jump to the
435       ** next iteration of the loop through the contents of the fifo.
436       */
437       sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, iRowid);
438 
439       /* Populate the OLD.* pseudo-table */
440       if( old_col_mask ){
441         sqlite3VdbeAddOp2(v, OP_RowData, iCur, iData);
442       }else{
443         sqlite3VdbeAddOp2(v, OP_Null, 0, iData);
444       }
445       sqlite3VdbeAddOp3(v, OP_Insert, oldIdx, iData, iRowid);
446 
447       /* Jump back and run the BEFORE triggers */
448       sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginBeforeTrigger);
449       sqlite3VdbeJumpHere(v, iEndBeforeTrigger);
450     }
451 
452     if( !isView ){
453       /* Delete the row */
454 #ifndef SQLITE_OMIT_VIRTUALTABLE
455       if( IsVirtual(pTab) ){
456         const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
457         sqlite3VtabMakeWritable(pParse, pTab);
458         sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iRowid, pVTab, P4_VTAB);
459       }else
460 #endif
461       {
462         sqlite3GenerateRowDelete(pParse, pTab, iCur, iRowid, pParse->nested==0);
463       }
464     }
465 
466     /* If there are row triggers, close all cursors then invoke
467     ** the AFTER triggers
468     */
469     if( pTrigger ){
470       /* Jump back and run the AFTER triggers */
471       sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginAfterTrigger);
472       sqlite3VdbeJumpHere(v, iEndAfterTrigger);
473     }
474 
475     /* End of the delete loop */
476     sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
477     sqlite3VdbeResolveLabel(v, end);
478 
479     /* Close the cursors after the loop if there are no row triggers */
480     if( !isView  && !IsVirtual(pTab) ){
481       for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
482         sqlite3VdbeAddOp2(v, OP_Close, iCur + i, pIdx->tnum);
483       }
484       sqlite3VdbeAddOp1(v, OP_Close, iCur);
485     }
486   }
487 
488   /* Update the sqlite_sequence table by storing the content of the
489   ** maximum rowid counter values recorded while inserting into
490   ** autoincrement tables.
491   */
492   if( pParse->nested==0 && pParse->trigStack==0 ){
493     sqlite3AutoincrementEnd(pParse);
494   }
495 
496   /*
497   ** Return the number of rows that were deleted. If this routine is
498   ** generating code because of a call to sqlite3NestedParse(), do not
499   ** invoke the callback function.
500   */
501   if( db->flags & SQLITE_CountRows && pParse->nested==0 && !pParse->trigStack ){
502     sqlite3VdbeAddOp2(v, OP_ResultRow, memCnt, 1);
503     sqlite3VdbeSetNumCols(v, 1);
504     sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows deleted", SQLITE_STATIC);
505   }
506 
507 delete_from_cleanup:
508   sqlite3AuthContextPop(&sContext);
509   sqlite3SrcListDelete(db, pTabList);
510   sqlite3ExprDelete(db, pWhere);
511   return;
512 }
513 
514 /*
515 ** This routine generates VDBE code that causes a single row of a
516 ** single table to be deleted.
517 **
518 ** The VDBE must be in a particular state when this routine is called.
519 ** These are the requirements:
520 **
521 **   1.  A read/write cursor pointing to pTab, the table containing the row
522 **       to be deleted, must be opened as cursor number "base".
523 **
524 **   2.  Read/write cursors for all indices of pTab must be open as
525 **       cursor number base+i for the i-th index.
526 **
527 **   3.  The record number of the row to be deleted must be stored in
528 **       memory cell iRowid.
529 **
530 ** This routine pops the top of the stack to remove the record number
531 ** and then generates code to remove both the table record and all index
532 ** entries that point to that record.
533 */
534 void sqlite3GenerateRowDelete(
535   Parse *pParse,     /* Parsing context */
536   Table *pTab,       /* Table containing the row to be deleted */
537   int iCur,          /* Cursor number for the table */
538   int iRowid,        /* Memory cell that contains the rowid to delete */
539   int count          /* Increment the row change counter */
540 ){
541   int addr;
542   Vdbe *v;
543 
544   v = pParse->pVdbe;
545   addr = sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, iRowid);
546   sqlite3GenerateRowIndexDelete(pParse, pTab, iCur, 0);
547   sqlite3VdbeAddOp2(v, OP_Delete, iCur, (count?OPFLAG_NCHANGE:0));
548   if( count ){
549     sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_STATIC);
550   }
551   sqlite3VdbeJumpHere(v, addr);
552 }
553 
554 /*
555 ** This routine generates VDBE code that causes the deletion of all
556 ** index entries associated with a single row of a single table.
557 **
558 ** The VDBE must be in a particular state when this routine is called.
559 ** These are the requirements:
560 **
561 **   1.  A read/write cursor pointing to pTab, the table containing the row
562 **       to be deleted, must be opened as cursor number "iCur".
563 **
564 **   2.  Read/write cursors for all indices of pTab must be open as
565 **       cursor number iCur+i for the i-th index.
566 **
567 **   3.  The "iCur" cursor must be pointing to the row that is to be
568 **       deleted.
569 */
570 void sqlite3GenerateRowIndexDelete(
571   Parse *pParse,     /* Parsing and code generating context */
572   Table *pTab,       /* Table containing the row to be deleted */
573   int iCur,          /* Cursor number for the table */
574   int *aRegIdx       /* Only delete if aRegIdx!=0 && aRegIdx[i]>0 */
575 ){
576   int i;
577   Index *pIdx;
578   int r1;
579 
580   for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
581     if( aRegIdx!=0 && aRegIdx[i-1]==0 ) continue;
582     r1 = sqlite3GenerateIndexKey(pParse, pIdx, iCur, 0, 0);
583     sqlite3VdbeAddOp3(pParse->pVdbe, OP_IdxDelete, iCur+i, r1,pIdx->nColumn+1);
584   }
585 }
586 
587 /*
588 ** Generate code that will assemble an index key and put it in register
589 ** regOut.  The key with be for index pIdx which is an index on pTab.
590 ** iCur is the index of a cursor open on the pTab table and pointing to
591 ** the entry that needs indexing.
592 **
593 ** Return a register number which is the first in a block of
594 ** registers that holds the elements of the index key.  The
595 ** block of registers has already been deallocated by the time
596 ** this routine returns.
597 */
598 int sqlite3GenerateIndexKey(
599   Parse *pParse,     /* Parsing context */
600   Index *pIdx,       /* The index for which to generate a key */
601   int iCur,          /* Cursor number for the pIdx->pTable table */
602   int regOut,        /* Write the new index key to this register */
603   int doMakeRec      /* Run the OP_MakeRecord instruction if true */
604 ){
605   Vdbe *v = pParse->pVdbe;
606   int j;
607   Table *pTab = pIdx->pTable;
608   int regBase;
609   int nCol;
610 
611   nCol = pIdx->nColumn;
612   regBase = sqlite3GetTempRange(pParse, nCol+1);
613   sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regBase+nCol);
614   for(j=0; j<nCol; j++){
615     int idx = pIdx->aiColumn[j];
616     if( idx==pTab->iPKey ){
617       sqlite3VdbeAddOp2(v, OP_SCopy, regBase+nCol, regBase+j);
618     }else{
619       sqlite3VdbeAddOp3(v, OP_Column, iCur, idx, regBase+j);
620       sqlite3ColumnDefault(v, pTab, idx, -1);
621     }
622   }
623   if( doMakeRec ){
624     sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol+1, regOut);
625     sqlite3VdbeChangeP4(v, -1, sqlite3IndexAffinityStr(v, pIdx), 0);
626     sqlite3ExprCacheAffinityChange(pParse, regBase, nCol+1);
627   }
628   sqlite3ReleaseTempRange(pParse, regBase, nCol+1);
629   return regBase;
630 }
631 
632 /* Make sure "isView" gets undefined in case this file becomes part of
633 ** the amalgamation - so that subsequent files do not see isView as a
634 ** macro. */
635 #undef isView
636