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| 1 /* | |
| 2 ** | |
| 3 ** The author disclaims copyright to this source code. In place of | |
| 4 ** a legal notice, here is a blessing: | |
| 5 ** | |
| 6 ** May you do good and not evil. | |
| 7 ** May you find forgiveness for yourself and forgive others. | |
| 8 ** May you share freely, never taking more than you give. | |
| 9 ** | |
| 10 ************************************************************************* | |
| 11 ** | |
| 12 ** | |
| 13 ** $Id: trigger.c,v 1.143 2009/08/10 03:57:58 shane Exp $ | |
| 14 */ | |
| 15 #include "sqliteInt.h" | |
| 16 | |
| 17 #ifndef SQLITE_OMIT_TRIGGER | |
| 18 /* | |
| 19 ** Delete a linked list of TriggerStep structures. | |
| 20 */ | |
| 21 void sqlite3DeleteTriggerStep(sqlite3 *db, TriggerStep *pTriggerStep){ | |
| 22 while( pTriggerStep ){ | |
| 23 TriggerStep * pTmp = pTriggerStep; | |
| 24 pTriggerStep = pTriggerStep->pNext; | |
| 25 | |
| 26 sqlite3ExprDelete(db, pTmp->pWhere); | |
| 27 sqlite3ExprListDelete(db, pTmp->pExprList); | |
| 28 sqlite3SelectDelete(db, pTmp->pSelect); | |
| 29 sqlite3IdListDelete(db, pTmp->pIdList); | |
| 30 | |
| 31 sqlite3DbFree(db, pTmp); | |
| 32 } | |
| 33 } | |
| 34 | |
| 35 /* | |
| 36 ** Given table pTab, return a list of all the triggers attached to | |
| 37 ** the table. The list is connected by Trigger.pNext pointers. | |
| 38 ** | |
| 39 ** All of the triggers on pTab that are in the same database as pTab | |
| 40 ** are already attached to pTab->pTrigger. But there might be additional | |
| 41 ** triggers on pTab in the TEMP schema. This routine prepends all | |
| 42 ** TEMP triggers on pTab to the beginning of the pTab->pTrigger list | |
| 43 ** and returns the combined list. | |
| 44 ** | |
| 45 ** To state it another way: This routine returns a list of all triggers | |
| 46 ** that fire off of pTab. The list will include any TEMP triggers on | |
| 47 ** pTab as well as the triggers lised in pTab->pTrigger. | |
| 48 */ | |
| 49 Trigger *sqlite3TriggerList(Parse *pParse, Table *pTab){ | |
| 50 Schema * const pTmpSchema = pParse->db->aDb[1].pSchema; | |
| 51 Trigger *pList = 0; /* List of triggers to return */ | |
| 52 | |
| 53 if( pTmpSchema!=pTab->pSchema ){ | |
| 54 HashElem *p; | |
| 55 for(p=sqliteHashFirst(&pTmpSchema->trigHash); p; p=sqliteHashNext(p)){ | |
| 56 Trigger *pTrig = (Trigger *)sqliteHashData(p); | |
| 57 if( pTrig->pTabSchema==pTab->pSchema | |
| 58 && 0==sqlite3StrICmp(pTrig->table, pTab->zName) | |
| 59 ){ | |
| 60 pTrig->pNext = (pList ? pList : pTab->pTrigger); | |
| 61 pList = pTrig; | |
| 62 } | |
| 63 } | |
| 64 } | |
| 65 | |
| 66 return (pList ? pList : pTab->pTrigger); | |
| 67 } | |
| 68 | |
| 69 /* | |
| 70 ** This is called by the parser when it sees a CREATE TRIGGER statement | |
| 71 ** up to the point of the BEGIN before the trigger actions. A Trigger | |
| 72 ** structure is generated based on the information available and stored | |
| 73 ** in pParse->pNewTrigger. After the trigger actions have been parsed, the | |
| 74 ** sqlite3FinishTrigger() function is called to complete the trigger | |
| 75 ** construction process. | |
| 76 */ | |
| 77 void sqlite3BeginTrigger( | |
| 78 Parse *pParse, /* The parse context of the CREATE TRIGGER statement */ | |
| 79 Token *pName1, /* The name of the trigger */ | |
| 80 Token *pName2, /* The name of the trigger */ | |
| 81 int tr_tm, /* One of TK_BEFORE, TK_AFTER, TK_INSTEAD */ | |
| 82 int op, /* One of TK_INSERT, TK_UPDATE, TK_DELETE */ | |
| 83 IdList *pColumns, /* column list if this is an UPDATE OF trigger */ | |
| 84 SrcList *pTableName,/* The name of the table/view the trigger applies to */ | |
| 85 Expr *pWhen, /* WHEN clause */ | |
| 86 int isTemp, /* True if the TEMPORARY keyword is present */ | |
| 87 int noErr /* Suppress errors if the trigger already exists */ | |
| 88 ){ | |
| 89 Trigger *pTrigger = 0; /* The new trigger */ | |
| 90 Table *pTab; /* Table that the trigger fires off of */ | |
| 91 char *zName = 0; /* Name of the trigger */ | |
| 92 sqlite3 *db = pParse->db; /* The database connection */ | |
| 93 int iDb; /* The database to store the trigger in */ | |
| 94 Token *pName; /* The unqualified db name */ | |
| 95 DbFixer sFix; /* State vector for the DB fixer */ | |
| 96 int iTabDb; /* Index of the database holding pTab */ | |
| 97 | |
| 98 assert( pName1!=0 ); /* pName1->z might be NULL, but not pName1 itself */ | |
| 99 assert( pName2!=0 ); | |
| 100 assert( op==TK_INSERT || op==TK_UPDATE || op==TK_DELETE ); | |
| 101 assert( op>0 && op<0xff ); | |
| 102 if( isTemp ){ | |
| 103 /* If TEMP was specified, then the trigger name may not be qualified. */ | |
| 104 if( pName2->n>0 ){ | |
| 105 sqlite3ErrorMsg(pParse, "temporary trigger may not have qualified name"); | |
| 106 goto trigger_cleanup; | |
| 107 } | |
| 108 iDb = 1; | |
| 109 pName = pName1; | |
| 110 }else{ | |
| 111 /* Figure out the db that the the trigger will be created in */ | |
| 112 iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName); | |
| 113 if( iDb<0 ){ | |
| 114 goto trigger_cleanup; | |
| 115 } | |
| 116 } | |
| 117 | |
| 118 /* If the trigger name was unqualified, and the table is a temp table, | |
| 119 ** then set iDb to 1 to create the trigger in the temporary database. | |
| 120 ** If sqlite3SrcListLookup() returns 0, indicating the table does not | |
| 121 ** exist, the error is caught by the block below. | |
| 122 */ | |
| 123 if( !pTableName || db->mallocFailed ){ | |
| 124 goto trigger_cleanup; | |
| 125 } | |
| 126 pTab = sqlite3SrcListLookup(pParse, pTableName); | |
| 127 if( pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){ | |
| 128 iDb = 1; | |
| 129 } | |
| 130 | |
| 131 /* Ensure the table name matches database name and that the table exists */ | |
| 132 if( db->mallocFailed ) goto trigger_cleanup; | |
| 133 assert( pTableName->nSrc==1 ); | |
| 134 if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", pName) && | |
| 135 sqlite3FixSrcList(&sFix, pTableName) ){ | |
| 136 goto trigger_cleanup; | |
| 137 } | |
| 138 pTab = sqlite3SrcListLookup(pParse, pTableName); | |
| 139 if( !pTab ){ | |
| 140 /* The table does not exist. */ | |
| 141 if( db->init.iDb==1 ){ | |
| 142 /* Ticket #3810. | |
| 143 ** Normally, whenever a table is dropped, all associated triggers are | |
| 144 ** dropped too. But if a TEMP trigger is created on a non-TEMP table | |
| 145 ** and the table is dropped by a different database connection, the | |
| 146 ** trigger is not visible to the database connection that does the | |
| 147 ** drop so the trigger cannot be dropped. This results in an | |
| 148 ** "orphaned trigger" - a trigger whose associated table is missing. | |
| 149 */ | |
| 150 db->init.orphanTrigger = 1; | |
| 151 } | |
| 152 goto trigger_cleanup; | |
| 153 } | |
| 154 if( IsVirtual(pTab) ){ | |
| 155 sqlite3ErrorMsg(pParse, "cannot create triggers on virtual tables"); | |
| 156 goto trigger_cleanup; | |
| 157 } | |
| 158 | |
| 159 /* Check that the trigger name is not reserved and that no trigger of the | |
| 160 ** specified name exists */ | |
| 161 zName = sqlite3NameFromToken(db, pName); | |
| 162 if( !zName || SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){ | |
| 163 goto trigger_cleanup; | |
| 164 } | |
| 165 if( sqlite3HashFind(&(db->aDb[iDb].pSchema->trigHash), | |
| 166 zName, sqlite3Strlen30(zName)) ){ | |
| 167 if( !noErr ){ | |
| 168 sqlite3ErrorMsg(pParse, "trigger %T already exists", pName); | |
| 169 } | |
| 170 goto trigger_cleanup; | |
| 171 } | |
| 172 | |
| 173 /* Do not create a trigger on a system table */ | |
| 174 if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){ | |
| 175 sqlite3ErrorMsg(pParse, "cannot create trigger on system table"); | |
| 176 pParse->nErr++; | |
| 177 goto trigger_cleanup; | |
| 178 } | |
| 179 | |
| 180 /* INSTEAD of triggers are only for views and views only support INSTEAD | |
| 181 ** of triggers. | |
| 182 */ | |
| 183 if( pTab->pSelect && tr_tm!=TK_INSTEAD ){ | |
| 184 sqlite3ErrorMsg(pParse, "cannot create %s trigger on view: %S", | |
| 185 (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName, 0); | |
| 186 goto trigger_cleanup; | |
| 187 } | |
| 188 if( !pTab->pSelect && tr_tm==TK_INSTEAD ){ | |
| 189 sqlite3ErrorMsg(pParse, "cannot create INSTEAD OF" | |
| 190 " trigger on table: %S", pTableName, 0); | |
| 191 goto trigger_cleanup; | |
| 192 } | |
| 193 iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema); | |
| 194 | |
| 195 #ifndef SQLITE_OMIT_AUTHORIZATION | |
| 196 { | |
| 197 int code = SQLITE_CREATE_TRIGGER; | |
| 198 const char *zDb = db->aDb[iTabDb].zName; | |
| 199 const char *zDbTrig = isTemp ? db->aDb[1].zName : zDb; | |
| 200 if( iTabDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER; | |
| 201 if( sqlite3AuthCheck(pParse, code, zName, pTab->zName, zDbTrig) ){ | |
| 202 goto trigger_cleanup; | |
| 203 } | |
| 204 if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(iTabDb),0,zDb)){ | |
| 205 goto trigger_cleanup; | |
| 206 } | |
| 207 } | |
| 208 #endif | |
| 209 | |
| 210 /* INSTEAD OF triggers can only appear on views and BEFORE triggers | |
| 211 ** cannot appear on views. So we might as well translate every | |
| 212 ** INSTEAD OF trigger into a BEFORE trigger. It simplifies code | |
| 213 ** elsewhere. | |
| 214 */ | |
| 215 if (tr_tm == TK_INSTEAD){ | |
| 216 tr_tm = TK_BEFORE; | |
| 217 } | |
| 218 | |
| 219 /* Build the Trigger object */ | |
| 220 pTrigger = (Trigger*)sqlite3DbMallocZero(db, sizeof(Trigger)); | |
| 221 if( pTrigger==0 ) goto trigger_cleanup; | |
| 222 pTrigger->zName = zName; | |
| 223 zName = 0; | |
| 224 pTrigger->table = sqlite3DbStrDup(db, pTableName->a[0].zName); | |
| 225 pTrigger->pSchema = db->aDb[iDb].pSchema; | |
| 226 pTrigger->pTabSchema = pTab->pSchema; | |
| 227 pTrigger->op = (u8)op; | |
| 228 pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER; | |
| 229 pTrigger->pWhen = sqlite3ExprDup(db, pWhen, EXPRDUP_REDUCE); | |
| 230 pTrigger->pColumns = sqlite3IdListDup(db, pColumns); | |
| 231 assert( pParse->pNewTrigger==0 ); | |
| 232 pParse->pNewTrigger = pTrigger; | |
| 233 | |
| 234 trigger_cleanup: | |
| 235 sqlite3DbFree(db, zName); | |
| 236 sqlite3SrcListDelete(db, pTableName); | |
| 237 sqlite3IdListDelete(db, pColumns); | |
| 238 sqlite3ExprDelete(db, pWhen); | |
| 239 if( !pParse->pNewTrigger ){ | |
| 240 sqlite3DeleteTrigger(db, pTrigger); | |
| 241 }else{ | |
| 242 assert( pParse->pNewTrigger==pTrigger ); | |
| 243 } | |
| 244 } | |
| 245 | |
| 246 /* | |
| 247 ** This routine is called after all of the trigger actions have been parsed | |
| 248 ** in order to complete the process of building the trigger. | |
| 249 */ | |
| 250 void sqlite3FinishTrigger( | |
| 251 Parse *pParse, /* Parser context */ | |
| 252 TriggerStep *pStepList, /* The triggered program */ | |
| 253 Token *pAll /* Token that describes the complete CREATE TRIGGER */ | |
| 254 ){ | |
| 255 Trigger *pTrig = pParse->pNewTrigger; /* Trigger being finished */ | |
| 256 char *zName; /* Name of trigger */ | |
| 257 sqlite3 *db = pParse->db; /* The database */ | |
| 258 DbFixer sFix; | |
| 259 int iDb; /* Database containing the trigger */ | |
| 260 Token nameToken; /* Trigger name for error reporting */ | |
| 261 | |
| 262 pTrig = pParse->pNewTrigger; | |
| 263 pParse->pNewTrigger = 0; | |
| 264 if( NEVER(pParse->nErr) || !pTrig ) goto triggerfinish_cleanup; | |
| 265 zName = pTrig->zName; | |
| 266 iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema); | |
| 267 pTrig->step_list = pStepList; | |
| 268 while( pStepList ){ | |
| 269 pStepList->pTrig = pTrig; | |
| 270 pStepList = pStepList->pNext; | |
| 271 } | |
| 272 nameToken.z = pTrig->zName; | |
| 273 nameToken.n = sqlite3Strlen30(nameToken.z); | |
| 274 if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", &nameToken) | |
| 275 && sqlite3FixTriggerStep(&sFix, pTrig->step_list) ){ | |
| 276 goto triggerfinish_cleanup; | |
| 277 } | |
| 278 | |
| 279 /* if we are not initializing, and this trigger is not on a TEMP table, | |
| 280 ** build the sqlite_master entry | |
| 281 */ | |
| 282 if( !db->init.busy ){ | |
| 283 Vdbe *v; | |
| 284 char *z; | |
| 285 | |
| 286 /* Make an entry in the sqlite_master table */ | |
| 287 v = sqlite3GetVdbe(pParse); | |
| 288 if( v==0 ) goto triggerfinish_cleanup; | |
| 289 sqlite3BeginWriteOperation(pParse, 0, iDb); | |
| 290 z = sqlite3DbStrNDup(db, (char*)pAll->z, pAll->n); | |
| 291 sqlite3NestedParse(pParse, | |
| 292 "INSERT INTO %Q.%s VALUES('trigger',%Q,%Q,0,'CREATE TRIGGER %q')", | |
| 293 db->aDb[iDb].zName, SCHEMA_TABLE(iDb), zName, | |
| 294 pTrig->table, z); | |
| 295 sqlite3DbFree(db, z); | |
| 296 sqlite3ChangeCookie(pParse, iDb); | |
| 297 sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 0, 0, sqlite3MPrintf( | |
| 298 db, "type='trigger' AND name='%q'", zName), P4_DYNAMIC | |
| 299 ); | |
| 300 } | |
| 301 | |
| 302 if( db->init.busy ){ | |
| 303 Trigger *pLink = pTrig; | |
| 304 Hash *pHash = &db->aDb[iDb].pSchema->trigHash; | |
| 305 pTrig = sqlite3HashInsert(pHash, zName, sqlite3Strlen30(zName), pTrig); | |
| 306 if( pTrig ){ | |
| 307 db->mallocFailed = 1; | |
| 308 }else if( pLink->pSchema==pLink->pTabSchema ){ | |
| 309 Table *pTab; | |
| 310 int n = sqlite3Strlen30(pLink->table); | |
| 311 pTab = sqlite3HashFind(&pLink->pTabSchema->tblHash, pLink->table, n); | |
| 312 assert( pTab!=0 ); | |
| 313 pLink->pNext = pTab->pTrigger; | |
| 314 pTab->pTrigger = pLink; | |
| 315 } | |
| 316 } | |
| 317 | |
| 318 triggerfinish_cleanup: | |
| 319 sqlite3DeleteTrigger(db, pTrig); | |
| 320 assert( !pParse->pNewTrigger ); | |
| 321 sqlite3DeleteTriggerStep(db, pStepList); | |
| 322 } | |
| 323 | |
| 324 /* | |
| 325 ** Turn a SELECT statement (that the pSelect parameter points to) into | |
| 326 ** a trigger step. Return a pointer to a TriggerStep structure. | |
| 327 ** | |
| 328 ** The parser calls this routine when it finds a SELECT statement in | |
| 329 ** body of a TRIGGER. | |
| 330 */ | |
| 331 TriggerStep *sqlite3TriggerSelectStep(sqlite3 *db, Select *pSelect){ | |
| 332 TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep)); | |
| 333 if( pTriggerStep==0 ) { | |
| 334 sqlite3SelectDelete(db, pSelect); | |
| 335 return 0; | |
| 336 } | |
| 337 pTriggerStep->op = TK_SELECT; | |
| 338 pTriggerStep->pSelect = pSelect; | |
| 339 pTriggerStep->orconf = OE_Default; | |
| 340 return pTriggerStep; | |
| 341 } | |
| 342 | |
| 343 /* | |
| 344 ** Allocate space to hold a new trigger step. The allocated space | |
| 345 ** holds both the TriggerStep object and the TriggerStep.target.z string. | |
| 346 ** | |
| 347 ** If an OOM error occurs, NULL is returned and db->mallocFailed is set. | |
| 348 */ | |
| 349 static TriggerStep *triggerStepAllocate( | |
| 350 sqlite3 *db, /* Database connection */ | |
| 351 u8 op, /* Trigger opcode */ | |
| 352 Token *pName /* The target name */ | |
| 353 ){ | |
| 354 TriggerStep *pTriggerStep; | |
| 355 | |
| 356 pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep) + pName->n); | |
| 357 if( pTriggerStep ){ | |
| 358 char *z = (char*)&pTriggerStep[1]; | |
| 359 memcpy(z, pName->z, pName->n); | |
| 360 pTriggerStep->target.z = z; | |
| 361 pTriggerStep->target.n = pName->n; | |
| 362 pTriggerStep->op = op; | |
| 363 } | |
| 364 return pTriggerStep; | |
| 365 } | |
| 366 | |
| 367 /* | |
| 368 ** Build a trigger step out of an INSERT statement. Return a pointer | |
| 369 ** to the new trigger step. | |
| 370 ** | |
| 371 ** The parser calls this routine when it sees an INSERT inside the | |
| 372 ** body of a trigger. | |
| 373 */ | |
| 374 TriggerStep *sqlite3TriggerInsertStep( | |
| 375 sqlite3 *db, /* The database connection */ | |
| 376 Token *pTableName, /* Name of the table into which we insert */ | |
| 377 IdList *pColumn, /* List of columns in pTableName to insert into */ | |
| 378 ExprList *pEList, /* The VALUE clause: a list of values to be inserted */ | |
| 379 Select *pSelect, /* A SELECT statement that supplies values */ | |
| 380 u8 orconf /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */ | |
| 381 ){ | |
| 382 TriggerStep *pTriggerStep; | |
| 383 | |
| 384 assert(pEList == 0 || pSelect == 0); | |
| 385 assert(pEList != 0 || pSelect != 0 || db->mallocFailed); | |
| 386 | |
| 387 pTriggerStep = triggerStepAllocate(db, TK_INSERT, pTableName); | |
| 388 if( pTriggerStep ){ | |
| 389 pTriggerStep->pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE); | |
| 390 pTriggerStep->pIdList = pColumn; | |
| 391 pTriggerStep->pExprList = sqlite3ExprListDup(db, pEList, EXPRDUP_REDUCE); | |
| 392 pTriggerStep->orconf = orconf; | |
| 393 }else{ | |
| 394 sqlite3IdListDelete(db, pColumn); | |
| 395 } | |
| 396 sqlite3ExprListDelete(db, pEList); | |
| 397 sqlite3SelectDelete(db, pSelect); | |
| 398 | |
| 399 return pTriggerStep; | |
| 400 } | |
| 401 | |
| 402 /* | |
| 403 ** Construct a trigger step that implements an UPDATE statement and return | |
| 404 ** a pointer to that trigger step. The parser calls this routine when it | |
| 405 ** sees an UPDATE statement inside the body of a CREATE TRIGGER. | |
| 406 */ | |
| 407 TriggerStep *sqlite3TriggerUpdateStep( | |
| 408 sqlite3 *db, /* The database connection */ | |
| 409 Token *pTableName, /* Name of the table to be updated */ | |
| 410 ExprList *pEList, /* The SET clause: list of column and new values */ | |
| 411 Expr *pWhere, /* The WHERE clause */ | |
| 412 u8 orconf /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */ | |
| 413 ){ | |
| 414 TriggerStep *pTriggerStep; | |
| 415 | |
| 416 pTriggerStep = triggerStepAllocate(db, TK_UPDATE, pTableName); | |
| 417 if( pTriggerStep ){ | |
| 418 pTriggerStep->pExprList = sqlite3ExprListDup(db, pEList, EXPRDUP_REDUCE); | |
| 419 pTriggerStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE); | |
| 420 pTriggerStep->orconf = orconf; | |
| 421 } | |
| 422 sqlite3ExprListDelete(db, pEList); | |
| 423 sqlite3ExprDelete(db, pWhere); | |
| 424 return pTriggerStep; | |
| 425 } | |
| 426 | |
| 427 /* | |
| 428 ** Construct a trigger step that implements a DELETE statement and return | |
| 429 ** a pointer to that trigger step. The parser calls this routine when it | |
| 430 ** sees a DELETE statement inside the body of a CREATE TRIGGER. | |
| 431 */ | |
| 432 TriggerStep *sqlite3TriggerDeleteStep( | |
| 433 sqlite3 *db, /* Database connection */ | |
| 434 Token *pTableName, /* The table from which rows are deleted */ | |
| 435 Expr *pWhere /* The WHERE clause */ | |
| 436 ){ | |
| 437 TriggerStep *pTriggerStep; | |
| 438 | |
| 439 pTriggerStep = triggerStepAllocate(db, TK_DELETE, pTableName); | |
| 440 if( pTriggerStep ){ | |
| 441 pTriggerStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE); | |
| 442 pTriggerStep->orconf = OE_Default; | |
| 443 } | |
| 444 sqlite3ExprDelete(db, pWhere); | |
| 445 return pTriggerStep; | |
| 446 } | |
| 447 | |
| 448 /* | |
| 449 ** Recursively delete a Trigger structure | |
| 450 */ | |
| 451 void sqlite3DeleteTrigger(sqlite3 *db, Trigger *pTrigger){ | |
| 452 if( pTrigger==0 ) return; | |
| 453 sqlite3DeleteTriggerStep(db, pTrigger->step_list); | |
| 454 sqlite3DbFree(db, pTrigger->zName); | |
| 455 sqlite3DbFree(db, pTrigger->table); | |
| 456 sqlite3ExprDelete(db, pTrigger->pWhen); | |
| 457 sqlite3IdListDelete(db, pTrigger->pColumns); | |
| 458 sqlite3DbFree(db, pTrigger); | |
| 459 } | |
| 460 | |
| 461 /* | |
| 462 ** This function is called to drop a trigger from the database schema. | |
| 463 ** | |
| 464 ** This may be called directly from the parser and therefore identifies | |
| 465 ** the trigger by name. The sqlite3DropTriggerPtr() routine does the | |
| 466 ** same job as this routine except it takes a pointer to the trigger | |
| 467 ** instead of the trigger name. | |
| 468 **/ | |
| 469 void sqlite3DropTrigger(Parse *pParse, SrcList *pName, int noErr){ | |
| 470 Trigger *pTrigger = 0; | |
| 471 int i; | |
| 472 const char *zDb; | |
| 473 const char *zName; | |
| 474 int nName; | |
| 475 sqlite3 *db = pParse->db; | |
| 476 | |
| 477 if( db->mallocFailed ) goto drop_trigger_cleanup; | |
| 478 if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){ | |
| 479 goto drop_trigger_cleanup; | |
| 480 } | |
| 481 | |
| 482 assert( pName->nSrc==1 ); | |
| 483 zDb = pName->a[0].zDatabase; | |
| 484 zName = pName->a[0].zName; | |
| 485 nName = sqlite3Strlen30(zName); | |
| 486 for(i=OMIT_TEMPDB; i<db->nDb; i++){ | |
| 487 int j = (i<2) ? i^1 : i; /* Search TEMP before MAIN */ | |
| 488 if( zDb && sqlite3StrICmp(db->aDb[j].zName, zDb) ) continue; | |
| 489 pTrigger = sqlite3HashFind(&(db->aDb[j].pSchema->trigHash), zName, nName); | |
| 490 if( pTrigger ) break; | |
| 491 } | |
| 492 if( !pTrigger ){ | |
| 493 if( !noErr ){ | |
| 494 sqlite3ErrorMsg(pParse, "no such trigger: %S", pName, 0); | |
| 495 } | |
| 496 goto drop_trigger_cleanup; | |
| 497 } | |
| 498 sqlite3DropTriggerPtr(pParse, pTrigger); | |
| 499 | |
| 500 drop_trigger_cleanup: | |
| 501 sqlite3SrcListDelete(db, pName); | |
| 502 } | |
| 503 | |
| 504 /* | |
| 505 ** Return a pointer to the Table structure for the table that a trigger | |
| 506 ** is set on. | |
| 507 */ | |
| 508 static Table *tableOfTrigger(Trigger *pTrigger){ | |
| 509 int n = sqlite3Strlen30(pTrigger->table); | |
| 510 return sqlite3HashFind(&pTrigger->pTabSchema->tblHash, pTrigger->table, n); | |
| 511 } | |
| 512 | |
| 513 | |
| 514 /* | |
| 515 ** Drop a trigger given a pointer to that trigger. | |
| 516 */ | |
| 517 void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger){ | |
| 518 Table *pTable; | |
| 519 Vdbe *v; | |
| 520 sqlite3 *db = pParse->db; | |
| 521 int iDb; | |
| 522 | |
| 523 iDb = sqlite3SchemaToIndex(pParse->db, pTrigger->pSchema); | |
| 524 assert( iDb>=0 && iDb<db->nDb ); | |
| 525 pTable = tableOfTrigger(pTrigger); | |
| 526 assert( pTable ); | |
| 527 assert( pTable->pSchema==pTrigger->pSchema || iDb==1 ); | |
| 528 #ifndef SQLITE_OMIT_AUTHORIZATION | |
| 529 { | |
| 530 int code = SQLITE_DROP_TRIGGER; | |
| 531 const char *zDb = db->aDb[iDb].zName; | |
| 532 const char *zTab = SCHEMA_TABLE(iDb); | |
| 533 if( iDb==1 ) code = SQLITE_DROP_TEMP_TRIGGER; | |
| 534 if( sqlite3AuthCheck(pParse, code, pTrigger->zName, pTable->zName, zDb) || | |
| 535 sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){ | |
| 536 return; | |
| 537 } | |
| 538 } | |
| 539 #endif | |
| 540 | |
| 541 /* Generate code to destroy the database record of the trigger. | |
| 542 */ | |
| 543 assert( pTable!=0 ); | |
| 544 if( (v = sqlite3GetVdbe(pParse))!=0 ){ | |
| 545 int base; | |
| 546 static const VdbeOpList dropTrigger[] = { | |
| 547 { OP_Rewind, 0, ADDR(9), 0}, | |
| 548 { OP_String8, 0, 1, 0}, /* 1 */ | |
| 549 { OP_Column, 0, 1, 2}, | |
| 550 { OP_Ne, 2, ADDR(8), 1}, | |
| 551 { OP_String8, 0, 1, 0}, /* 4: "trigger" */ | |
| 552 { OP_Column, 0, 0, 2}, | |
| 553 { OP_Ne, 2, ADDR(8), 1}, | |
| 554 { OP_Delete, 0, 0, 0}, | |
| 555 { OP_Next, 0, ADDR(1), 0}, /* 8 */ | |
| 556 }; | |
| 557 | |
| 558 sqlite3BeginWriteOperation(pParse, 0, iDb); | |
| 559 sqlite3OpenMasterTable(pParse, iDb); | |
| 560 base = sqlite3VdbeAddOpList(v, ArraySize(dropTrigger), dropTrigger); | |
| 561 sqlite3VdbeChangeP4(v, base+1, pTrigger->zName, 0); | |
| 562 sqlite3VdbeChangeP4(v, base+4, "trigger", P4_STATIC); | |
| 563 sqlite3ChangeCookie(pParse, iDb); | |
| 564 sqlite3VdbeAddOp2(v, OP_Close, 0, 0); | |
| 565 sqlite3VdbeAddOp4(v, OP_DropTrigger, iDb, 0, 0, pTrigger->zName, 0); | |
| 566 if( pParse->nMem<3 ){ | |
| 567 pParse->nMem = 3; | |
| 568 } | |
| 569 } | |
| 570 } | |
| 571 | |
| 572 /* | |
| 573 ** Remove a trigger from the hash tables of the sqlite* pointer. | |
| 574 */ | |
| 575 void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){ | |
| 576 Hash *pHash = &(db->aDb[iDb].pSchema->trigHash); | |
| 577 Trigger *pTrigger; | |
| 578 pTrigger = sqlite3HashInsert(pHash, zName, sqlite3Strlen30(zName), 0); | |
| 579 if( ALWAYS(pTrigger) ){ | |
| 580 if( pTrigger->pSchema==pTrigger->pTabSchema ){ | |
| 581 Table *pTab = tableOfTrigger(pTrigger); | |
| 582 Trigger **pp; | |
| 583 for(pp=&pTab->pTrigger; *pp!=pTrigger; pp=&((*pp)->pNext)); | |
| 584 *pp = (*pp)->pNext; | |
| 585 } | |
| 586 sqlite3DeleteTrigger(db, pTrigger); | |
| 587 db->flags |= SQLITE_InternChanges; | |
| 588 } | |
| 589 } | |
| 590 | |
| 591 /* | |
| 592 ** pEList is the SET clause of an UPDATE statement. Each entry | |
| 593 ** in pEList is of the format <id>=<expr>. If any of the entries | |
| 594 ** in pEList have an <id> which matches an identifier in pIdList, | |
| 595 ** then return TRUE. If pIdList==NULL, then it is considered a | |
| 596 ** wildcard that matches anything. Likewise if pEList==NULL then | |
| 597 ** it matches anything so always return true. Return false only | |
| 598 ** if there is no match. | |
| 599 */ | |
| 600 static int checkColumnOverlap(IdList *pIdList, ExprList *pEList){ | |
| 601 int e; | |
| 602 if( pIdList==0 || NEVER(pEList==0) ) return 1; | |
| 603 for(e=0; e<pEList->nExpr; e++){ | |
| 604 if( sqlite3IdListIndex(pIdList, pEList->a[e].zName)>=0 ) return 1; | |
| 605 } | |
| 606 return 0; | |
| 607 } | |
| 608 | |
| 609 /* | |
| 610 ** Return a list of all triggers on table pTab if there exists at least | |
| 611 ** one trigger that must be fired when an operation of type 'op' is | |
| 612 ** performed on the table, and, if that operation is an UPDATE, if at | |
| 613 ** least one of the columns in pChanges is being modified. | |
| 614 */ | |
| 615 Trigger *sqlite3TriggersExist( | |
| 616 Parse *pParse, /* Parse context */ | |
| 617 Table *pTab, /* The table the contains the triggers */ | |
| 618 int op, /* one of TK_DELETE, TK_INSERT, TK_UPDATE */ | |
| 619 ExprList *pChanges, /* Columns that change in an UPDATE statement */ | |
| 620 int *pMask /* OUT: Mask of TRIGGER_BEFORE|TRIGGER_AFTER */ | |
| 621 ){ | |
| 622 int mask = 0; | |
| 623 Trigger *pList = sqlite3TriggerList(pParse, pTab); | |
| 624 Trigger *p; | |
| 625 assert( pList==0 || IsVirtual(pTab)==0 ); | |
| 626 for(p=pList; p; p=p->pNext){ | |
| 627 if( p->op==op && checkColumnOverlap(p->pColumns, pChanges) ){ | |
| 628 mask |= p->tr_tm; | |
| 629 } | |
| 630 } | |
| 631 if( pMask ){ | |
| 632 *pMask = mask; | |
| 633 } | |
| 634 return (mask ? pList : 0); | |
| 635 } | |
| 636 | |
| 637 /* | |
| 638 ** Convert the pStep->target token into a SrcList and return a pointer | |
| 639 ** to that SrcList. | |
| 640 ** | |
| 641 ** This routine adds a specific database name, if needed, to the target when | |
| 642 ** forming the SrcList. This prevents a trigger in one database from | |
| 643 ** referring to a target in another database. An exception is when the | |
| 644 ** trigger is in TEMP in which case it can refer to any other database it | |
| 645 ** wants. | |
| 646 */ | |
| 647 static SrcList *targetSrcList( | |
| 648 Parse *pParse, /* The parsing context */ | |
| 649 TriggerStep *pStep /* The trigger containing the target token */ | |
| 650 ){ | |
| 651 int iDb; /* Index of the database to use */ | |
| 652 SrcList *pSrc; /* SrcList to be returned */ | |
| 653 | |
| 654 pSrc = sqlite3SrcListAppend(pParse->db, 0, &pStep->target, 0); | |
| 655 if( pSrc ){ | |
| 656 assert( pSrc->nSrc>0 ); | |
| 657 assert( pSrc->a!=0 ); | |
| 658 iDb = sqlite3SchemaToIndex(pParse->db, pStep->pTrig->pSchema); | |
| 659 if( iDb==0 || iDb>=2 ){ | |
| 660 sqlite3 *db = pParse->db; | |
| 661 assert( iDb<pParse->db->nDb ); | |
| 662 pSrc->a[pSrc->nSrc-1].zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zName); | |
| 663 } | |
| 664 } | |
| 665 return pSrc; | |
| 666 } | |
| 667 | |
| 668 /* | |
| 669 ** Generate VDBE code for the statements inside the body of a single | |
| 670 ** trigger. | |
| 671 */ | |
| 672 static int codeTriggerProgram( | |
| 673 Parse *pParse, /* The parser context */ | |
| 674 TriggerStep *pStepList, /* List of statements inside the trigger body */ | |
| 675 int orconf /* Conflict algorithm. (OE_Abort, etc) */ | |
| 676 ){ | |
| 677 TriggerStep *pStep; | |
| 678 Vdbe *v = pParse->pVdbe; | |
| 679 sqlite3 *db = pParse->db; | |
| 680 | |
| 681 assert( pParse->pTriggerTab && pParse->pToplevel ); | |
| 682 assert( pStepList ); | |
| 683 assert( v!=0 ); | |
| 684 for(pStep=pStepList; pStep; pStep=pStep->pNext){ | |
| 685 /* Figure out the ON CONFLICT policy that will be used for this step | |
| 686 ** of the trigger program. If the statement that caused this trigger | |
| 687 ** to fire had an explicit ON CONFLICT, then use it. Otherwise, use | |
| 688 ** the ON CONFLICT policy that was specified as part of the trigger | |
| 689 ** step statement. Example: | |
| 690 ** | |
| 691 ** CREATE TRIGGER AFTER INSERT ON t1 BEGIN; | |
| 692 ** INSERT OR REPLACE INTO t2 VALUES(new.a, new.b); | |
| 693 ** END; | |
| 694 ** | |
| 695 ** INSERT INTO t1 ... ; -- insert into t2 uses REPLACE policy | |
| 696 ** INSERT OR IGNORE INTO t1 ... ; -- insert into t2 uses IGNORE policy | |
| 697 */ | |
| 698 pParse->eOrconf = (orconf==OE_Default)?pStep->orconf:(u8)orconf; | |
| 699 | |
| 700 switch( pStep->op ){ | |
| 701 case TK_UPDATE: { | |
| 702 sqlite3Update(pParse, | |
| 703 targetSrcList(pParse, pStep), | |
| 704 sqlite3ExprListDup(db, pStep->pExprList, 0), | |
| 705 sqlite3ExprDup(db, pStep->pWhere, 0), | |
| 706 pParse->eOrconf | |
| 707 ); | |
| 708 break; | |
| 709 } | |
| 710 case TK_INSERT: { | |
| 711 sqlite3Insert(pParse, | |
| 712 targetSrcList(pParse, pStep), | |
| 713 sqlite3ExprListDup(db, pStep->pExprList, 0), | |
| 714 sqlite3SelectDup(db, pStep->pSelect, 0), | |
| 715 sqlite3IdListDup(db, pStep->pIdList), | |
| 716 pParse->eOrconf | |
| 717 ); | |
| 718 break; | |
| 719 } | |
| 720 case TK_DELETE: { | |
| 721 sqlite3DeleteFrom(pParse, | |
| 722 targetSrcList(pParse, pStep), | |
| 723 sqlite3ExprDup(db, pStep->pWhere, 0) | |
| 724 ); | |
| 725 break; | |
| 726 } | |
| 727 default: assert( pStep->op==TK_SELECT ); { | |
| 728 SelectDest sDest; | |
| 729 Select *pSelect = sqlite3SelectDup(db, pStep->pSelect, 0); | |
| 730 sqlite3SelectDestInit(&sDest, SRT_Discard, 0); | |
| 731 sqlite3Select(pParse, pSelect, &sDest); | |
| 732 sqlite3SelectDelete(db, pSelect); | |
| 733 break; | |
| 734 } | |
| 735 } | |
| 736 if( pStep->op!=TK_SELECT ){ | |
| 737 sqlite3VdbeAddOp0(v, OP_ResetCount); | |
| 738 } | |
| 739 } | |
| 740 | |
| 741 return 0; | |
| 742 } | |
| 743 | |
| 744 #ifdef SQLITE_DEBUG | |
| 745 /* | |
| 746 ** This function is used to add VdbeComment() annotations to a VDBE | |
| 747 ** program. It is not used in production code, only for debugging. | |
| 748 */ | |
| 749 static const char *onErrorText(int onError){ | |
| 750 switch( onError ){ | |
| 751 case OE_Abort: return "abort"; | |
| 752 case OE_Rollback: return "rollback"; | |
| 753 case OE_Fail: return "fail"; | |
| 754 case OE_Replace: return "replace"; | |
| 755 case OE_Ignore: return "ignore"; | |
| 756 case OE_Default: return "default"; | |
| 757 } | |
| 758 return "n/a"; | |
| 759 } | |
| 760 #endif | |
| 761 | |
| 762 /* | |
| 763 ** Parse context structure pFrom has just been used to create a sub-vdbe | |
| 764 ** (trigger program). If an error has occurred, transfer error information | |
| 765 ** from pFrom to pTo. | |
| 766 */ | |
| 767 static void transferParseError(Parse *pTo, Parse *pFrom){ | |
| 768 assert( pFrom->zErrMsg==0 || pFrom->nErr ); | |
| 769 assert( pTo->zErrMsg==0 || pTo->nErr ); | |
| 770 if( pTo->nErr==0 ){ | |
| 771 pTo->zErrMsg = pFrom->zErrMsg; | |
| 772 pTo->nErr = pFrom->nErr; | |
| 773 }else{ | |
| 774 sqlite3DbFree(pFrom->db, pFrom->zErrMsg); | |
| 775 } | |
| 776 } | |
| 777 | |
| 778 /* | |
| 779 ** Create and populate a new TriggerPrg object with a sub-program | |
| 780 ** implementing trigger pTrigger with ON CONFLICT policy orconf. | |
| 781 */ | |
| 782 static TriggerPrg *codeRowTrigger( | |
| 783 Parse *pParse, /* Current parse context */ | |
| 784 Trigger *pTrigger, /* Trigger to code */ | |
| 785 Table *pTab, /* The table pTrigger is attached to */ | |
| 786 int orconf /* ON CONFLICT policy to code trigger program with */ | |
| 787 ){ | |
| 788 Parse *pTop = sqlite3ParseToplevel(pParse); | |
| 789 sqlite3 *db = pParse->db; /* Database handle */ | |
| 790 TriggerPrg *pPrg; /* Value to return */ | |
| 791 Expr *pWhen = 0; /* Duplicate of trigger WHEN expression */ | |
| 792 Vdbe *v; /* Temporary VM */ | |
| 793 NameContext sNC; /* Name context for sub-vdbe */ | |
| 794 SubProgram *pProgram = 0; /* Sub-vdbe for trigger program */ | |
| 795 Parse *pSubParse; /* Parse context for sub-vdbe */ | |
| 796 int iEndTrigger = 0; /* Label to jump to if WHEN is false */ | |
| 797 | |
| 798 assert( pTab==tableOfTrigger(pTrigger) ); | |
| 799 | |
| 800 /* Allocate the TriggerPrg and SubProgram objects. To ensure that they | |
| 801 ** are freed if an error occurs, link them into the Parse.pTriggerPrg | |
| 802 ** list of the top-level Parse object sooner rather than later. */ | |
| 803 pPrg = sqlite3DbMallocZero(db, sizeof(TriggerPrg)); | |
| 804 if( !pPrg ) return 0; | |
| 805 pPrg->pNext = pTop->pTriggerPrg; | |
| 806 pTop->pTriggerPrg = pPrg; | |
| 807 pPrg->pProgram = pProgram = sqlite3DbMallocZero(db, sizeof(SubProgram)); | |
| 808 if( !pProgram ) return 0; | |
| 809 pProgram->nRef = 1; | |
| 810 pPrg->pTrigger = pTrigger; | |
| 811 pPrg->orconf = orconf; | |
| 812 | |
| 813 /* Allocate and populate a new Parse context to use for coding the | |
| 814 ** trigger sub-program. */ | |
| 815 pSubParse = sqlite3StackAllocZero(db, sizeof(Parse)); | |
| 816 if( !pSubParse ) return 0; | |
| 817 memset(&sNC, 0, sizeof(sNC)); | |
| 818 sNC.pParse = pSubParse; | |
| 819 pSubParse->db = db; | |
| 820 pSubParse->pTriggerTab = pTab; | |
| 821 pSubParse->pToplevel = pTop; | |
| 822 pSubParse->zAuthContext = pTrigger->zName; | |
| 823 pSubParse->eTriggerOp = pTrigger->op; | |
| 824 | |
| 825 v = sqlite3GetVdbe(pSubParse); | |
| 826 if( v ){ | |
| 827 VdbeComment((v, "Start: %s.%s (%s %s%s%s ON %s)", | |
| 828 pTrigger->zName, onErrorText(orconf), | |
| 829 (pTrigger->tr_tm==TRIGGER_BEFORE ? "BEFORE" : "AFTER"), | |
| 830 (pTrigger->op==TK_UPDATE ? "UPDATE" : ""), | |
| 831 (pTrigger->op==TK_INSERT ? "INSERT" : ""), | |
| 832 (pTrigger->op==TK_DELETE ? "DELETE" : ""), | |
| 833 pTab->zName | |
| 834 )); | |
| 835 #ifndef SQLITE_OMIT_TRACE | |
| 836 sqlite3VdbeChangeP4(v, -1, | |
| 837 sqlite3MPrintf(db, "-- TRIGGER %s", pTrigger->zName), P4_DYNAMIC | |
| 838 ); | |
| 839 #endif | |
| 840 | |
| 841 /* If one was specified, code the WHEN clause. If it evaluates to false | |
| 842 ** (or NULL) the sub-vdbe is immediately halted by jumping to the | |
| 843 ** OP_Halt inserted at the end of the program. */ | |
| 844 if( pTrigger->pWhen ){ | |
| 845 pWhen = sqlite3ExprDup(db, pTrigger->pWhen, 0); | |
| 846 if( SQLITE_OK==sqlite3ResolveExprNames(&sNC, pWhen) | |
| 847 && db->mallocFailed==0 | |
| 848 ){ | |
| 849 iEndTrigger = sqlite3VdbeMakeLabel(v); | |
| 850 sqlite3ExprIfFalse(pSubParse, pWhen, iEndTrigger, SQLITE_JUMPIFNULL); | |
| 851 } | |
| 852 sqlite3ExprDelete(db, pWhen); | |
| 853 } | |
| 854 | |
| 855 /* Code the trigger program into the sub-vdbe. */ | |
| 856 codeTriggerProgram(pSubParse, pTrigger->step_list, orconf); | |
| 857 | |
| 858 /* Insert an OP_Halt at the end of the sub-program. */ | |
| 859 if( iEndTrigger ){ | |
| 860 sqlite3VdbeResolveLabel(v, iEndTrigger); | |
| 861 } | |
| 862 sqlite3VdbeAddOp0(v, OP_Halt); | |
| 863 VdbeComment((v, "End: %s.%s", pTrigger->zName, onErrorText(orconf))); | |
| 864 | |
| 865 transferParseError(pParse, pSubParse); | |
| 866 if( db->mallocFailed==0 ){ | |
| 867 pProgram->aOp = sqlite3VdbeTakeOpArray(v, &pProgram->nOp, &pTop->nMaxArg); | |
| 868 } | |
| 869 pProgram->nMem = pSubParse->nMem; | |
| 870 pProgram->nCsr = pSubParse->nTab; | |
| 871 pProgram->token = (void *)pTrigger; | |
| 872 pPrg->oldmask = pSubParse->oldmask; | |
| 873 sqlite3VdbeDelete(v); | |
| 874 } | |
| 875 | |
| 876 assert( !pSubParse->pAinc && !pSubParse->pZombieTab ); | |
| 877 assert( !pSubParse->pTriggerPrg && !pSubParse->nMaxArg ); | |
| 878 sqlite3StackFree(db, pSubParse); | |
| 879 | |
| 880 return pPrg; | |
| 881 } | |
| 882 | |
| 883 /* | |
| 884 ** Return a pointer to a TriggerPrg object containing the sub-program for | |
| 885 ** trigger pTrigger with default ON CONFLICT algorithm orconf. If no such | |
| 886 ** TriggerPrg object exists, a new object is allocated and populated before | |
| 887 ** being returned. | |
| 888 */ | |
| 889 static TriggerPrg *getRowTrigger( | |
| 890 Parse *pParse, /* Current parse context */ | |
| 891 Trigger *pTrigger, /* Trigger to code */ | |
| 892 Table *pTab, /* The table trigger pTrigger is attached to */ | |
| 893 int orconf /* ON CONFLICT algorithm. */ | |
| 894 ){ | |
| 895 Parse *pRoot = sqlite3ParseToplevel(pParse); | |
| 896 TriggerPrg *pPrg; | |
| 897 | |
| 898 assert( pTab==tableOfTrigger(pTrigger) ); | |
| 899 | |
| 900 /* It may be that this trigger has already been coded (or is in the | |
| 901 ** process of being coded). If this is the case, then an entry with | |
| 902 ** a matching TriggerPrg.pTrigger field will be present somewhere | |
| 903 ** in the Parse.pTriggerPrg list. Search for such an entry. */ | |
| 904 for(pPrg=pRoot->pTriggerPrg; | |
| 905 pPrg && (pPrg->pTrigger!=pTrigger || pPrg->orconf!=orconf); | |
| 906 pPrg=pPrg->pNext | |
| 907 ); | |
| 908 | |
| 909 /* If an existing TriggerPrg could not be located, create a new one. */ | |
| 910 if( !pPrg ){ | |
| 911 pPrg = codeRowTrigger(pParse, pTrigger, pTab, orconf); | |
| 912 } | |
| 913 | |
| 914 return pPrg; | |
| 915 } | |
| 916 | |
| 917 /* | |
| 918 ** This is called to code FOR EACH ROW triggers. | |
| 919 ** | |
| 920 ** When the code that this function generates is executed, the following | |
| 921 ** must be true: | |
| 922 ** | |
| 923 ** 1. No cursors may be open in the main database. (But newIdx and oldIdx | |
| 924 ** can be indices of cursors in temporary tables. See below.) | |
| 925 ** | |
| 926 ** 2. If the triggers being coded are ON INSERT or ON UPDATE triggers, then | |
| 927 ** a temporary vdbe cursor (index newIdx) must be open and pointing at | |
| 928 ** a row containing values to be substituted for new.* expressions in the | |
| 929 ** trigger program(s). | |
| 930 ** | |
| 931 ** 3. If the triggers being coded are ON DELETE or ON UPDATE triggers, then | |
| 932 ** a temporary vdbe cursor (index oldIdx) must be open and pointing at | |
| 933 ** a row containing values to be substituted for old.* expressions in the | |
| 934 ** trigger program(s). | |
| 935 ** | |
| 936 ** If they are not NULL, the piOldColMask and piNewColMask output variables | |
| 937 ** are set to values that describe the columns used by the trigger program | |
| 938 ** in the OLD.* and NEW.* tables respectively. If column N of the | |
| 939 ** pseudo-table is read at least once, the corresponding bit of the output | |
| 940 ** mask is set. If a column with an index greater than 32 is read, the | |
| 941 ** output mask is set to the special value 0xffffffff. | |
| 942 ** | |
| 943 */ | |
| 944 void sqlite3CodeRowTrigger( | |
| 945 Parse *pParse, /* Parse context */ | |
| 946 Trigger *pTrigger, /* List of triggers on table pTab */ | |
| 947 int op, /* One of TK_UPDATE, TK_INSERT, TK_DELETE */ | |
| 948 ExprList *pChanges, /* Changes list for any UPDATE OF triggers */ | |
| 949 int tr_tm, /* One of TRIGGER_BEFORE, TRIGGER_AFTER */ | |
| 950 Table *pTab, /* The table to code triggers from */ | |
| 951 int newIdx, /* The indice of the "new" row to access */ | |
| 952 int oldIdx, /* The indice of the "old" row to access */ | |
| 953 int orconf, /* ON CONFLICT policy */ | |
| 954 int ignoreJump /* Instruction to jump to for RAISE(IGNORE) */ | |
| 955 ){ | |
| 956 Trigger *p; | |
| 957 | |
| 958 UNUSED_PARAMETER(newIdx); | |
| 959 | |
| 960 assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE); | |
| 961 assert(tr_tm == TRIGGER_BEFORE || tr_tm == TRIGGER_AFTER ); | |
| 962 | |
| 963 for(p=pTrigger; p; p=p->pNext){ | |
| 964 | |
| 965 /* Sanity checking: The schema for the trigger and for the table are | |
| 966 ** always defined. The trigger must be in the same schema as the table | |
| 967 ** or else it must be a TEMP trigger. */ | |
| 968 assert( p->pSchema!=0 ); | |
| 969 assert( p->pTabSchema!=0 ); | |
| 970 assert( p->pSchema==p->pTabSchema | |
| 971 || p->pSchema==pParse->db->aDb[1].pSchema ); | |
| 972 | |
| 973 /* Determine whether we should code this trigger */ | |
| 974 if( p->op==op | |
| 975 && p->tr_tm==tr_tm | |
| 976 && checkColumnOverlap(p->pColumns,pChanges) | |
| 977 ){ | |
| 978 Vdbe *v = sqlite3GetVdbe(pParse); /* Main VM */ | |
| 979 TriggerPrg *pPrg; | |
| 980 pPrg = getRowTrigger(pParse, p, pTab, orconf); | |
| 981 assert( pPrg || pParse->nErr || pParse->db->mallocFailed ); | |
| 982 | |
| 983 /* Code the OP_Program opcode in the parent VDBE. P4 of the OP_Program | |
| 984 ** is a pointer to the sub-vdbe containing the trigger program. */ | |
| 985 if( pPrg ){ | |
| 986 sqlite3VdbeAddOp3(v, OP_Program, oldIdx, ignoreJump, ++pParse->nMem); | |
| 987 pPrg->pProgram->nRef++; | |
| 988 sqlite3VdbeChangeP4(v, -1, (const char *)pPrg->pProgram, P4_SUBPROGRAM); | |
| 989 VdbeComment((v, "Call: %s.%s", p->zName, onErrorText(orconf))); | |
| 990 } | |
| 991 } | |
| 992 } | |
| 993 } | |
| 994 | |
| 995 /* | |
| 996 ** Triggers fired by UPDATE or DELETE statements may access values stored | |
| 997 ** in the old.* pseudo-table. This function returns a 32-bit bitmask | |
| 998 ** indicating which columns of the old.* table actually are used by | |
| 999 ** triggers. This information may be used by the caller to avoid having | |
| 1000 ** to load the entire old.* record into memory when executing an UPDATE | |
| 1001 ** or DELETE command. | |
| 1002 ** | |
| 1003 ** Bit 0 of the returned mask is set if the left-most column of the | |
| 1004 ** table may be accessed using an old.<col> reference. Bit 1 is set if | |
| 1005 ** the second leftmost column value is required, and so on. If there | |
| 1006 ** are more than 32 columns in the table, and at least one of the columns | |
| 1007 ** with an index greater than 32 may be accessed, 0xffffffff is returned. | |
| 1008 ** | |
| 1009 ** It is not possible to determine if the old.rowid column is accessed | |
| 1010 ** by triggers. The caller must always assume that it is. | |
| 1011 ** | |
| 1012 ** There is no equivalent function for new.* references. | |
| 1013 */ | |
| 1014 u32 sqlite3TriggerOldmask( | |
| 1015 Parse *pParse, /* Parse context */ | |
| 1016 Trigger *pTrigger, /* List of triggers on table pTab */ | |
| 1017 int op, /* Either TK_UPDATE or TK_DELETE */ | |
| 1018 ExprList *pChanges, /* Changes list for any UPDATE OF triggers */ | |
| 1019 Table *pTab, /* The table to code triggers from */ | |
| 1020 int orconf /* Default ON CONFLICT policy for trigger steps */ | |
| 1021 ){ | |
| 1022 u32 mask = 0; | |
| 1023 Trigger *p; | |
| 1024 | |
| 1025 assert(op==TK_UPDATE || op==TK_DELETE); | |
| 1026 for(p=pTrigger; p; p=p->pNext){ | |
| 1027 if( p->op==op && checkColumnOverlap(p->pColumns,pChanges) ){ | |
| 1028 TriggerPrg *pPrg; | |
| 1029 pPrg = getRowTrigger(pParse, p, pTab, orconf); | |
| 1030 if( pPrg ){ | |
| 1031 mask |= pPrg->oldmask; | |
| 1032 } | |
| 1033 } | |
| 1034 } | |
| 1035 | |
| 1036 return mask; | |
| 1037 } | |
| 1038 | |
| 1039 #endif /* !defined(SQLITE_OMIT_TRIGGER) */ | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 3108030:
Move bundled copy of sqlite one level deeper to better separate it... (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src/