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