00001 /* 00002 ** 00003 ** The author disclaims copyright to this source code. In place of 00004 ** a legal notice, here is a blessing: 00005 ** 00006 ** May you do good and not evil. 00007 ** May you find forgiveness for yourself and forgive others. 00008 ** May you share freely, never taking more than you give. 00009 ** 00010 ************************************************************************* 00011 ** 00012 ** 00013 ** $Id: trigger.c,v 1.129 2008/08/20 16:35:10 drh Exp $ 00014 */ 00015 #include "sqliteInt.h" 00016 00017 #ifndef SQLITE_OMIT_TRIGGER 00018 /* 00019 ** Delete a linked list of TriggerStep structures. 00020 */ 00021 void sqlite3DeleteTriggerStep(sqlite3 *db, TriggerStep *pTriggerStep){ 00022 while( pTriggerStep ){ 00023 TriggerStep * pTmp = pTriggerStep; 00024 pTriggerStep = pTriggerStep->pNext; 00025 00026 if( pTmp->target.dyn ) sqlite3DbFree(db, (char*)pTmp->target.z); 00027 sqlite3ExprDelete(db, pTmp->pWhere); 00028 sqlite3ExprListDelete(db, pTmp->pExprList); 00029 sqlite3SelectDelete(db, pTmp->pSelect); 00030 sqlite3IdListDelete(db, pTmp->pIdList); 00031 00032 sqlite3DbFree(db, pTmp); 00033 } 00034 } 00035 00036 /* 00037 ** This is called by the parser when it sees a CREATE TRIGGER statement 00038 ** up to the point of the BEGIN before the trigger actions. A Trigger 00039 ** structure is generated based on the information available and stored 00040 ** in pParse->pNewTrigger. After the trigger actions have been parsed, the 00041 ** sqlite3FinishTrigger() function is called to complete the trigger 00042 ** construction process. 00043 */ 00044 void sqlite3BeginTrigger( 00045 Parse *pParse, /* The parse context of the CREATE TRIGGER statement */ 00046 Token *pName1, /* The name of the trigger */ 00047 Token *pName2, /* The name of the trigger */ 00048 int tr_tm, /* One of TK_BEFORE, TK_AFTER, TK_INSTEAD */ 00049 int op, /* One of TK_INSERT, TK_UPDATE, TK_DELETE */ 00050 IdList *pColumns, /* column list if this is an UPDATE OF trigger */ 00051 SrcList *pTableName,/* The name of the table/view the trigger applies to */ 00052 Expr *pWhen, /* WHEN clause */ 00053 int isTemp, /* True if the TEMPORARY keyword is present */ 00054 int noErr /* Suppress errors if the trigger already exists */ 00055 ){ 00056 Trigger *pTrigger = 0; 00057 Table *pTab; 00058 char *zName = 0; /* Name of the trigger */ 00059 sqlite3 *db = pParse->db; 00060 int iDb; /* The database to store the trigger in */ 00061 Token *pName; /* The unqualified db name */ 00062 DbFixer sFix; 00063 int iTabDb; 00064 00065 assert( pName1!=0 ); /* pName1->z might be NULL, but not pName1 itself */ 00066 assert( pName2!=0 ); 00067 if( isTemp ){ 00068 /* If TEMP was specified, then the trigger name may not be qualified. */ 00069 if( pName2->n>0 ){ 00070 sqlite3ErrorMsg(pParse, "temporary trigger may not have qualified name"); 00071 goto trigger_cleanup; 00072 } 00073 iDb = 1; 00074 pName = pName1; 00075 }else{ 00076 /* Figure out the db that the the trigger will be created in */ 00077 iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName); 00078 if( iDb<0 ){ 00079 goto trigger_cleanup; 00080 } 00081 } 00082 00083 /* If the trigger name was unqualified, and the table is a temp table, 00084 ** then set iDb to 1 to create the trigger in the temporary database. 00085 ** If sqlite3SrcListLookup() returns 0, indicating the table does not 00086 ** exist, the error is caught by the block below. 00087 */ 00088 if( !pTableName || db->mallocFailed ){ 00089 goto trigger_cleanup; 00090 } 00091 pTab = sqlite3SrcListLookup(pParse, pTableName); 00092 if( pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){ 00093 iDb = 1; 00094 } 00095 00096 /* Ensure the table name matches database name and that the table exists */ 00097 if( db->mallocFailed ) goto trigger_cleanup; 00098 assert( pTableName->nSrc==1 ); 00099 if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", pName) && 00100 sqlite3FixSrcList(&sFix, pTableName) ){ 00101 goto trigger_cleanup; 00102 } 00103 pTab = sqlite3SrcListLookup(pParse, pTableName); 00104 if( !pTab ){ 00105 /* The table does not exist. */ 00106 goto trigger_cleanup; 00107 } 00108 if( IsVirtual(pTab) ){ 00109 sqlite3ErrorMsg(pParse, "cannot create triggers on virtual tables"); 00110 goto trigger_cleanup; 00111 } 00112 00113 /* Check that the trigger name is not reserved and that no trigger of the 00114 ** specified name exists */ 00115 zName = sqlite3NameFromToken(db, pName); 00116 if( !zName || SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){ 00117 goto trigger_cleanup; 00118 } 00119 if( sqlite3HashFind(&(db->aDb[iDb].pSchema->trigHash), zName,strlen(zName)) ){ 00120 if( !noErr ){ 00121 sqlite3ErrorMsg(pParse, "trigger %T already exists", pName); 00122 } 00123 goto trigger_cleanup; 00124 } 00125 00126 /* Do not create a trigger on a system table */ 00127 if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){ 00128 sqlite3ErrorMsg(pParse, "cannot create trigger on system table"); 00129 pParse->nErr++; 00130 goto trigger_cleanup; 00131 } 00132 00133 /* INSTEAD of triggers are only for views and views only support INSTEAD 00134 ** of triggers. 00135 */ 00136 if( pTab->pSelect && tr_tm!=TK_INSTEAD ){ 00137 sqlite3ErrorMsg(pParse, "cannot create %s trigger on view: %S", 00138 (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName, 0); 00139 goto trigger_cleanup; 00140 } 00141 if( !pTab->pSelect && tr_tm==TK_INSTEAD ){ 00142 sqlite3ErrorMsg(pParse, "cannot create INSTEAD OF" 00143 " trigger on table: %S", pTableName, 0); 00144 goto trigger_cleanup; 00145 } 00146 iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema); 00147 00148 #ifndef SQLITE_OMIT_AUTHORIZATION 00149 { 00150 int code = SQLITE_CREATE_TRIGGER; 00151 const char *zDb = db->aDb[iTabDb].zName; 00152 const char *zDbTrig = isTemp ? db->aDb[1].zName : zDb; 00153 if( iTabDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER; 00154 if( sqlite3AuthCheck(pParse, code, zName, pTab->zName, zDbTrig) ){ 00155 goto trigger_cleanup; 00156 } 00157 if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(iTabDb),0,zDb)){ 00158 goto trigger_cleanup; 00159 } 00160 } 00161 #endif 00162 00163 /* INSTEAD OF triggers can only appear on views and BEFORE triggers 00164 ** cannot appear on views. So we might as well translate every 00165 ** INSTEAD OF trigger into a BEFORE trigger. It simplifies code 00166 ** elsewhere. 00167 */ 00168 if (tr_tm == TK_INSTEAD){ 00169 tr_tm = TK_BEFORE; 00170 } 00171 00172 /* Build the Trigger object */ 00173 pTrigger = (Trigger*)sqlite3DbMallocZero(db, sizeof(Trigger)); 00174 if( pTrigger==0 ) goto trigger_cleanup; 00175 pTrigger->name = zName; 00176 zName = 0; 00177 pTrigger->table = sqlite3DbStrDup(db, pTableName->a[0].zName); 00178 pTrigger->pSchema = db->aDb[iDb].pSchema; 00179 pTrigger->pTabSchema = pTab->pSchema; 00180 pTrigger->op = op; 00181 pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER; 00182 pTrigger->pWhen = sqlite3ExprDup(db, pWhen); 00183 pTrigger->pColumns = sqlite3IdListDup(db, pColumns); 00184 sqlite3TokenCopy(db, &pTrigger->nameToken,pName); 00185 assert( pParse->pNewTrigger==0 ); 00186 pParse->pNewTrigger = pTrigger; 00187 00188 trigger_cleanup: 00189 sqlite3DbFree(db, zName); 00190 sqlite3SrcListDelete(db, pTableName); 00191 sqlite3IdListDelete(db, pColumns); 00192 sqlite3ExprDelete(db, pWhen); 00193 if( !pParse->pNewTrigger ){ 00194 sqlite3DeleteTrigger(db, pTrigger); 00195 }else{ 00196 assert( pParse->pNewTrigger==pTrigger ); 00197 } 00198 } 00199 00200 /* 00201 ** This routine is called after all of the trigger actions have been parsed 00202 ** in order to complete the process of building the trigger. 00203 */ 00204 void sqlite3FinishTrigger( 00205 Parse *pParse, /* Parser context */ 00206 TriggerStep *pStepList, /* The triggered program */ 00207 Token *pAll /* Token that describes the complete CREATE TRIGGER */ 00208 ){ 00209 Trigger *pTrig = 0; /* The trigger whose construction is finishing up */ 00210 sqlite3 *db = pParse->db; /* The database */ 00211 DbFixer sFix; 00212 int iDb; /* Database containing the trigger */ 00213 00214 pTrig = pParse->pNewTrigger; 00215 pParse->pNewTrigger = 0; 00216 if( pParse->nErr || !pTrig ) goto triggerfinish_cleanup; 00217 iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema); 00218 pTrig->step_list = pStepList; 00219 while( pStepList ){ 00220 pStepList->pTrig = pTrig; 00221 pStepList = pStepList->pNext; 00222 } 00223 if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", &pTrig->nameToken) 00224 && sqlite3FixTriggerStep(&sFix, pTrig->step_list) ){ 00225 goto triggerfinish_cleanup; 00226 } 00227 00228 /* if we are not initializing, and this trigger is not on a TEMP table, 00229 ** build the sqlite_master entry 00230 */ 00231 if( !db->init.busy ){ 00232 Vdbe *v; 00233 char *z; 00234 00235 /* Make an entry in the sqlite_master table */ 00236 v = sqlite3GetVdbe(pParse); 00237 if( v==0 ) goto triggerfinish_cleanup; 00238 sqlite3BeginWriteOperation(pParse, 0, iDb); 00239 z = sqlite3DbStrNDup(db, (char*)pAll->z, pAll->n); 00240 sqlite3NestedParse(pParse, 00241 "INSERT INTO %Q.%s VALUES('trigger',%Q,%Q,0,'CREATE TRIGGER %q')", 00242 db->aDb[iDb].zName, SCHEMA_TABLE(iDb), pTrig->name, 00243 pTrig->table, z); 00244 sqlite3DbFree(db, z); 00245 sqlite3ChangeCookie(pParse, iDb); 00246 sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 0, 0, sqlite3MPrintf( 00247 db, "type='trigger' AND name='%q'", pTrig->name), P4_DYNAMIC 00248 ); 00249 } 00250 00251 if( db->init.busy ){ 00252 int n; 00253 Table *pTab; 00254 Trigger *pDel; 00255 pDel = sqlite3HashInsert(&db->aDb[iDb].pSchema->trigHash, 00256 pTrig->name, strlen(pTrig->name), pTrig); 00257 if( pDel ){ 00258 assert( pDel==pTrig ); 00259 db->mallocFailed = 1; 00260 goto triggerfinish_cleanup; 00261 } 00262 n = strlen(pTrig->table) + 1; 00263 pTab = sqlite3HashFind(&pTrig->pTabSchema->tblHash, pTrig->table, n); 00264 assert( pTab!=0 ); 00265 pTrig->pNext = pTab->pTrigger; 00266 pTab->pTrigger = pTrig; 00267 pTrig = 0; 00268 } 00269 00270 triggerfinish_cleanup: 00271 sqlite3DeleteTrigger(db, pTrig); 00272 assert( !pParse->pNewTrigger ); 00273 sqlite3DeleteTriggerStep(db, pStepList); 00274 } 00275 00276 /* 00277 ** Make a copy of all components of the given trigger step. This has 00278 ** the effect of copying all Expr.token.z values into memory obtained 00279 ** from sqlite3_malloc(). As initially created, the Expr.token.z values 00280 ** all point to the input string that was fed to the parser. But that 00281 ** string is ephemeral - it will go away as soon as the sqlite3_exec() 00282 ** call that started the parser exits. This routine makes a persistent 00283 ** copy of all the Expr.token.z strings so that the TriggerStep structure 00284 ** will be valid even after the sqlite3_exec() call returns. 00285 */ 00286 static void sqlitePersistTriggerStep(sqlite3 *db, TriggerStep *p){ 00287 if( p->target.z ){ 00288 p->target.z = (u8*)sqlite3DbStrNDup(db, (char*)p->target.z, p->target.n); 00289 p->target.dyn = 1; 00290 } 00291 if( p->pSelect ){ 00292 Select *pNew = sqlite3SelectDup(db, p->pSelect); 00293 sqlite3SelectDelete(db, p->pSelect); 00294 p->pSelect = pNew; 00295 } 00296 if( p->pWhere ){ 00297 Expr *pNew = sqlite3ExprDup(db, p->pWhere); 00298 sqlite3ExprDelete(db, p->pWhere); 00299 p->pWhere = pNew; 00300 } 00301 if( p->pExprList ){ 00302 ExprList *pNew = sqlite3ExprListDup(db, p->pExprList); 00303 sqlite3ExprListDelete(db, p->pExprList); 00304 p->pExprList = pNew; 00305 } 00306 if( p->pIdList ){ 00307 IdList *pNew = sqlite3IdListDup(db, p->pIdList); 00308 sqlite3IdListDelete(db, p->pIdList); 00309 p->pIdList = pNew; 00310 } 00311 } 00312 00313 /* 00314 ** Turn a SELECT statement (that the pSelect parameter points to) into 00315 ** a trigger step. Return a pointer to a TriggerStep structure. 00316 ** 00317 ** The parser calls this routine when it finds a SELECT statement in 00318 ** body of a TRIGGER. 00319 */ 00320 TriggerStep *sqlite3TriggerSelectStep(sqlite3 *db, Select *pSelect){ 00321 TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep)); 00322 if( pTriggerStep==0 ) { 00323 sqlite3SelectDelete(db, pSelect); 00324 return 0; 00325 } 00326 00327 pTriggerStep->op = TK_SELECT; 00328 pTriggerStep->pSelect = pSelect; 00329 pTriggerStep->orconf = OE_Default; 00330 sqlitePersistTriggerStep(db, pTriggerStep); 00331 00332 return pTriggerStep; 00333 } 00334 00335 /* 00336 ** Build a trigger step out of an INSERT statement. Return a pointer 00337 ** to the new trigger step. 00338 ** 00339 ** The parser calls this routine when it sees an INSERT inside the 00340 ** body of a trigger. 00341 */ 00342 TriggerStep *sqlite3TriggerInsertStep( 00343 sqlite3 *db, /* The database connection */ 00344 Token *pTableName, /* Name of the table into which we insert */ 00345 IdList *pColumn, /* List of columns in pTableName to insert into */ 00346 ExprList *pEList, /* The VALUE clause: a list of values to be inserted */ 00347 Select *pSelect, /* A SELECT statement that supplies values */ 00348 int orconf /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */ 00349 ){ 00350 TriggerStep *pTriggerStep; 00351 00352 assert(pEList == 0 || pSelect == 0); 00353 assert(pEList != 0 || pSelect != 0 || db->mallocFailed); 00354 00355 pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep)); 00356 if( pTriggerStep ){ 00357 pTriggerStep->op = TK_INSERT; 00358 pTriggerStep->pSelect = pSelect; 00359 pTriggerStep->target = *pTableName; 00360 pTriggerStep->pIdList = pColumn; 00361 pTriggerStep->pExprList = pEList; 00362 pTriggerStep->orconf = orconf; 00363 sqlitePersistTriggerStep(db, pTriggerStep); 00364 }else{ 00365 sqlite3IdListDelete(db, pColumn); 00366 sqlite3ExprListDelete(db, pEList); 00367 sqlite3SelectDelete(db, pSelect); 00368 } 00369 00370 return pTriggerStep; 00371 } 00372 00373 /* 00374 ** Construct a trigger step that implements an UPDATE statement and return 00375 ** a pointer to that trigger step. The parser calls this routine when it 00376 ** sees an UPDATE statement inside the body of a CREATE TRIGGER. 00377 */ 00378 TriggerStep *sqlite3TriggerUpdateStep( 00379 sqlite3 *db, /* The database connection */ 00380 Token *pTableName, /* Name of the table to be updated */ 00381 ExprList *pEList, /* The SET clause: list of column and new values */ 00382 Expr *pWhere, /* The WHERE clause */ 00383 int orconf /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */ 00384 ){ 00385 TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep)); 00386 if( pTriggerStep==0 ){ 00387 sqlite3ExprListDelete(db, pEList); 00388 sqlite3ExprDelete(db, pWhere); 00389 return 0; 00390 } 00391 00392 pTriggerStep->op = TK_UPDATE; 00393 pTriggerStep->target = *pTableName; 00394 pTriggerStep->pExprList = pEList; 00395 pTriggerStep->pWhere = pWhere; 00396 pTriggerStep->orconf = orconf; 00397 sqlitePersistTriggerStep(db, pTriggerStep); 00398 00399 return pTriggerStep; 00400 } 00401 00402 /* 00403 ** Construct a trigger step that implements a DELETE statement and return 00404 ** a pointer to that trigger step. The parser calls this routine when it 00405 ** sees a DELETE statement inside the body of a CREATE TRIGGER. 00406 */ 00407 TriggerStep *sqlite3TriggerDeleteStep( 00408 sqlite3 *db, /* Database connection */ 00409 Token *pTableName, /* The table from which rows are deleted */ 00410 Expr *pWhere /* The WHERE clause */ 00411 ){ 00412 TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep)); 00413 if( pTriggerStep==0 ){ 00414 sqlite3ExprDelete(db, pWhere); 00415 return 0; 00416 } 00417 00418 pTriggerStep->op = TK_DELETE; 00419 pTriggerStep->target = *pTableName; 00420 pTriggerStep->pWhere = pWhere; 00421 pTriggerStep->orconf = OE_Default; 00422 sqlitePersistTriggerStep(db, pTriggerStep); 00423 00424 return pTriggerStep; 00425 } 00426 00427 /* 00428 ** Recursively delete a Trigger structure 00429 */ 00430 void sqlite3DeleteTrigger(sqlite3 *db, Trigger *pTrigger){ 00431 if( pTrigger==0 ) return; 00432 sqlite3DeleteTriggerStep(db, pTrigger->step_list); 00433 sqlite3DbFree(db, pTrigger->name); 00434 sqlite3DbFree(db, pTrigger->table); 00435 sqlite3ExprDelete(db, pTrigger->pWhen); 00436 sqlite3IdListDelete(db, pTrigger->pColumns); 00437 if( pTrigger->nameToken.dyn ) sqlite3DbFree(db, (char*)pTrigger->nameToken.z); 00438 sqlite3DbFree(db, pTrigger); 00439 } 00440 00441 /* 00442 ** This function is called to drop a trigger from the database schema. 00443 ** 00444 ** This may be called directly from the parser and therefore identifies 00445 ** the trigger by name. The sqlite3DropTriggerPtr() routine does the 00446 ** same job as this routine except it takes a pointer to the trigger 00447 ** instead of the trigger name. 00448 **/ 00449 void sqlite3DropTrigger(Parse *pParse, SrcList *pName, int noErr){ 00450 Trigger *pTrigger = 0; 00451 int i; 00452 const char *zDb; 00453 const char *zName; 00454 int nName; 00455 sqlite3 *db = pParse->db; 00456 00457 if( db->mallocFailed ) goto drop_trigger_cleanup; 00458 if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){ 00459 goto drop_trigger_cleanup; 00460 } 00461 00462 assert( pName->nSrc==1 ); 00463 zDb = pName->a[0].zDatabase; 00464 zName = pName->a[0].zName; 00465 nName = strlen(zName); 00466 for(i=OMIT_TEMPDB; i<db->nDb; i++){ 00467 int j = (i<2) ? i^1 : i; /* Search TEMP before MAIN */ 00468 if( zDb && sqlite3StrICmp(db->aDb[j].zName, zDb) ) continue; 00469 pTrigger = sqlite3HashFind(&(db->aDb[j].pSchema->trigHash), zName, nName); 00470 if( pTrigger ) break; 00471 } 00472 if( !pTrigger ){ 00473 if( !noErr ){ 00474 sqlite3ErrorMsg(pParse, "no such trigger: %S", pName, 0); 00475 } 00476 goto drop_trigger_cleanup; 00477 } 00478 sqlite3DropTriggerPtr(pParse, pTrigger); 00479 00480 drop_trigger_cleanup: 00481 sqlite3SrcListDelete(db, pName); 00482 } 00483 00484 /* 00485 ** Return a pointer to the Table structure for the table that a trigger 00486 ** is set on. 00487 */ 00488 static Table *tableOfTrigger(Trigger *pTrigger){ 00489 int n = strlen(pTrigger->table) + 1; 00490 return sqlite3HashFind(&pTrigger->pTabSchema->tblHash, pTrigger->table, n); 00491 } 00492 00493 00494 /* 00495 ** Drop a trigger given a pointer to that trigger. 00496 */ 00497 void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger){ 00498 Table *pTable; 00499 Vdbe *v; 00500 sqlite3 *db = pParse->db; 00501 int iDb; 00502 00503 iDb = sqlite3SchemaToIndex(pParse->db, pTrigger->pSchema); 00504 assert( iDb>=0 && iDb<db->nDb ); 00505 pTable = tableOfTrigger(pTrigger); 00506 assert( pTable ); 00507 assert( pTable->pSchema==pTrigger->pSchema || iDb==1 ); 00508 #ifndef SQLITE_OMIT_AUTHORIZATION 00509 { 00510 int code = SQLITE_DROP_TRIGGER; 00511 const char *zDb = db->aDb[iDb].zName; 00512 const char *zTab = SCHEMA_TABLE(iDb); 00513 if( iDb==1 ) code = SQLITE_DROP_TEMP_TRIGGER; 00514 if( sqlite3AuthCheck(pParse, code, pTrigger->name, pTable->zName, zDb) || 00515 sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){ 00516 return; 00517 } 00518 } 00519 #endif 00520 00521 /* Generate code to destroy the database record of the trigger. 00522 */ 00523 assert( pTable!=0 ); 00524 if( (v = sqlite3GetVdbe(pParse))!=0 ){ 00525 int base; 00526 static const VdbeOpList dropTrigger[] = { 00527 { OP_Rewind, 0, ADDR(9), 0}, 00528 { OP_String8, 0, 1, 0}, /* 1 */ 00529 { OP_Column, 0, 1, 2}, 00530 { OP_Ne, 2, ADDR(8), 1}, 00531 { OP_String8, 0, 1, 0}, /* 4: "trigger" */ 00532 { OP_Column, 0, 0, 2}, 00533 { OP_Ne, 2, ADDR(8), 1}, 00534 { OP_Delete, 0, 0, 0}, 00535 { OP_Next, 0, ADDR(1), 0}, /* 8 */ 00536 }; 00537 00538 sqlite3BeginWriteOperation(pParse, 0, iDb); 00539 sqlite3OpenMasterTable(pParse, iDb); 00540 base = sqlite3VdbeAddOpList(v, ArraySize(dropTrigger), dropTrigger); 00541 sqlite3VdbeChangeP4(v, base+1, pTrigger->name, 0); 00542 sqlite3VdbeChangeP4(v, base+4, "trigger", P4_STATIC); 00543 sqlite3ChangeCookie(pParse, iDb); 00544 sqlite3VdbeAddOp2(v, OP_Close, 0, 0); 00545 sqlite3VdbeAddOp4(v, OP_DropTrigger, iDb, 0, 0, pTrigger->name, 0); 00546 } 00547 } 00548 00549 /* 00550 ** Remove a trigger from the hash tables of the sqlite* pointer. 00551 */ 00552 void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){ 00553 Trigger *pTrigger; 00554 int nName = strlen(zName); 00555 pTrigger = sqlite3HashInsert(&(db->aDb[iDb].pSchema->trigHash), 00556 zName, nName, 0); 00557 if( pTrigger ){ 00558 Table *pTable = tableOfTrigger(pTrigger); 00559 assert( pTable!=0 ); 00560 if( pTable->pTrigger == pTrigger ){ 00561 pTable->pTrigger = pTrigger->pNext; 00562 }else{ 00563 Trigger *cc = pTable->pTrigger; 00564 while( cc ){ 00565 if( cc->pNext == pTrigger ){ 00566 cc->pNext = cc->pNext->pNext; 00567 break; 00568 } 00569 cc = cc->pNext; 00570 } 00571 assert(cc); 00572 } 00573 sqlite3DeleteTrigger(db, pTrigger); 00574 db->flags |= SQLITE_InternChanges; 00575 } 00576 } 00577 00578 /* 00579 ** pEList is the SET clause of an UPDATE statement. Each entry 00580 ** in pEList is of the format <id>=<expr>. If any of the entries 00581 ** in pEList have an <id> which matches an identifier in pIdList, 00582 ** then return TRUE. If pIdList==NULL, then it is considered a 00583 ** wildcard that matches anything. Likewise if pEList==NULL then 00584 ** it matches anything so always return true. Return false only 00585 ** if there is no match. 00586 */ 00587 static int checkColumnOverLap(IdList *pIdList, ExprList *pEList){ 00588 int e; 00589 if( !pIdList || !pEList ) return 1; 00590 for(e=0; e<pEList->nExpr; e++){ 00591 if( sqlite3IdListIndex(pIdList, pEList->a[e].zName)>=0 ) return 1; 00592 } 00593 return 0; 00594 } 00595 00596 /* 00597 ** Return a bit vector to indicate what kind of triggers exist for operation 00598 ** "op" on table pTab. If pChanges is not NULL then it is a list of columns 00599 ** that are being updated. Triggers only match if the ON clause of the 00600 ** trigger definition overlaps the set of columns being updated. 00601 ** 00602 ** The returned bit vector is some combination of TRIGGER_BEFORE and 00603 ** TRIGGER_AFTER. 00604 */ 00605 int sqlite3TriggersExist( 00606 Parse *pParse, /* Used to check for recursive triggers */ 00607 Table *pTab, /* The table the contains the triggers */ 00608 int op, /* one of TK_DELETE, TK_INSERT, TK_UPDATE */ 00609 ExprList *pChanges /* Columns that change in an UPDATE statement */ 00610 ){ 00611 Trigger *pTrigger; 00612 int mask = 0; 00613 00614 pTrigger = IsVirtual(pTab) ? 0 : pTab->pTrigger; 00615 while( pTrigger ){ 00616 if( pTrigger->op==op && checkColumnOverLap(pTrigger->pColumns, pChanges) ){ 00617 mask |= pTrigger->tr_tm; 00618 } 00619 pTrigger = pTrigger->pNext; 00620 } 00621 return mask; 00622 } 00623 00624 /* 00625 ** Convert the pStep->target token into a SrcList and return a pointer 00626 ** to that SrcList. 00627 ** 00628 ** This routine adds a specific database name, if needed, to the target when 00629 ** forming the SrcList. This prevents a trigger in one database from 00630 ** referring to a target in another database. An exception is when the 00631 ** trigger is in TEMP in which case it can refer to any other database it 00632 ** wants. 00633 */ 00634 static SrcList *targetSrcList( 00635 Parse *pParse, /* The parsing context */ 00636 TriggerStep *pStep /* The trigger containing the target token */ 00637 ){ 00638 Token sDb; /* Dummy database name token */ 00639 int iDb; /* Index of the database to use */ 00640 SrcList *pSrc; /* SrcList to be returned */ 00641 00642 iDb = sqlite3SchemaToIndex(pParse->db, pStep->pTrig->pSchema); 00643 if( iDb==0 || iDb>=2 ){ 00644 assert( iDb<pParse->db->nDb ); 00645 sDb.z = (u8*)pParse->db->aDb[iDb].zName; 00646 sDb.n = strlen((char*)sDb.z); 00647 pSrc = sqlite3SrcListAppend(pParse->db, 0, &sDb, &pStep->target); 00648 } else { 00649 pSrc = sqlite3SrcListAppend(pParse->db, 0, &pStep->target, 0); 00650 } 00651 return pSrc; 00652 } 00653 00654 /* 00655 ** Generate VDBE code for zero or more statements inside the body of a 00656 ** trigger. 00657 */ 00658 static int codeTriggerProgram( 00659 Parse *pParse, /* The parser context */ 00660 TriggerStep *pStepList, /* List of statements inside the trigger body */ 00661 int orconfin /* Conflict algorithm. (OE_Abort, etc) */ 00662 ){ 00663 TriggerStep * pTriggerStep = pStepList; 00664 int orconf; 00665 Vdbe *v = pParse->pVdbe; 00666 sqlite3 *db = pParse->db; 00667 00668 assert( pTriggerStep!=0 ); 00669 assert( v!=0 ); 00670 sqlite3VdbeAddOp2(v, OP_ContextPush, 0, 0); 00671 VdbeComment((v, "begin trigger %s", pStepList->pTrig->name)); 00672 while( pTriggerStep ){ 00673 orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin; 00674 pParse->trigStack->orconf = orconf; 00675 switch( pTriggerStep->op ){ 00676 case TK_SELECT: { 00677 Select *ss = sqlite3SelectDup(db, pTriggerStep->pSelect); 00678 if( ss ){ 00679 SelectDest dest; 00680 00681 sqlite3SelectDestInit(&dest, SRT_Discard, 0); 00682 sqlite3Select(pParse, ss, &dest); 00683 sqlite3SelectDelete(db, ss); 00684 } 00685 break; 00686 } 00687 case TK_UPDATE: { 00688 SrcList *pSrc; 00689 pSrc = targetSrcList(pParse, pTriggerStep); 00690 sqlite3VdbeAddOp2(v, OP_ResetCount, 0, 0); 00691 sqlite3Update(pParse, pSrc, 00692 sqlite3ExprListDup(db, pTriggerStep->pExprList), 00693 sqlite3ExprDup(db, pTriggerStep->pWhere), orconf); 00694 sqlite3VdbeAddOp2(v, OP_ResetCount, 1, 0); 00695 break; 00696 } 00697 case TK_INSERT: { 00698 SrcList *pSrc; 00699 pSrc = targetSrcList(pParse, pTriggerStep); 00700 sqlite3VdbeAddOp2(v, OP_ResetCount, 0, 0); 00701 sqlite3Insert(pParse, pSrc, 00702 sqlite3ExprListDup(db, pTriggerStep->pExprList), 00703 sqlite3SelectDup(db, pTriggerStep->pSelect), 00704 sqlite3IdListDup(db, pTriggerStep->pIdList), orconf); 00705 sqlite3VdbeAddOp2(v, OP_ResetCount, 1, 0); 00706 break; 00707 } 00708 case TK_DELETE: { 00709 SrcList *pSrc; 00710 sqlite3VdbeAddOp2(v, OP_ResetCount, 0, 0); 00711 pSrc = targetSrcList(pParse, pTriggerStep); 00712 sqlite3DeleteFrom(pParse, pSrc, 00713 sqlite3ExprDup(db, pTriggerStep->pWhere)); 00714 sqlite3VdbeAddOp2(v, OP_ResetCount, 1, 0); 00715 break; 00716 } 00717 default: 00718 assert(0); 00719 } 00720 pTriggerStep = pTriggerStep->pNext; 00721 } 00722 sqlite3VdbeAddOp2(v, OP_ContextPop, 0, 0); 00723 VdbeComment((v, "end trigger %s", pStepList->pTrig->name)); 00724 00725 return 0; 00726 } 00727 00728 /* 00729 ** This is called to code FOR EACH ROW triggers. 00730 ** 00731 ** When the code that this function generates is executed, the following 00732 ** must be true: 00733 ** 00734 ** 1. No cursors may be open in the main database. (But newIdx and oldIdx 00735 ** can be indices of cursors in temporary tables. See below.) 00736 ** 00737 ** 2. If the triggers being coded are ON INSERT or ON UPDATE triggers, then 00738 ** a temporary vdbe cursor (index newIdx) must be open and pointing at 00739 ** a row containing values to be substituted for new.* expressions in the 00740 ** trigger program(s). 00741 ** 00742 ** 3. If the triggers being coded are ON DELETE or ON UPDATE triggers, then 00743 ** a temporary vdbe cursor (index oldIdx) must be open and pointing at 00744 ** a row containing values to be substituted for old.* expressions in the 00745 ** trigger program(s). 00746 ** 00747 ** If they are not NULL, the piOldColMask and piNewColMask output variables 00748 ** are set to values that describe the columns used by the trigger program 00749 ** in the OLD.* and NEW.* tables respectively. If column N of the 00750 ** pseudo-table is read at least once, the corresponding bit of the output 00751 ** mask is set. If a column with an index greater than 32 is read, the 00752 ** output mask is set to the special value 0xffffffff. 00753 ** 00754 */ 00755 int sqlite3CodeRowTrigger( 00756 Parse *pParse, /* Parse context */ 00757 int op, /* One of TK_UPDATE, TK_INSERT, TK_DELETE */ 00758 ExprList *pChanges, /* Changes list for any UPDATE OF triggers */ 00759 int tr_tm, /* One of TRIGGER_BEFORE, TRIGGER_AFTER */ 00760 Table *pTab, /* The table to code triggers from */ 00761 int newIdx, /* The indice of the "new" row to access */ 00762 int oldIdx, /* The indice of the "old" row to access */ 00763 int orconf, /* ON CONFLICT policy */ 00764 int ignoreJump, /* Instruction to jump to for RAISE(IGNORE) */ 00765 u32 *piOldColMask, /* OUT: Mask of columns used from the OLD.* table */ 00766 u32 *piNewColMask /* OUT: Mask of columns used from the NEW.* table */ 00767 ){ 00768 Trigger *p; 00769 sqlite3 *db = pParse->db; 00770 TriggerStack trigStackEntry; 00771 00772 trigStackEntry.oldColMask = 0; 00773 trigStackEntry.newColMask = 0; 00774 00775 assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE); 00776 assert(tr_tm == TRIGGER_BEFORE || tr_tm == TRIGGER_AFTER ); 00777 00778 assert(newIdx != -1 || oldIdx != -1); 00779 00780 for(p=pTab->pTrigger; p; p=p->pNext){ 00781 int fire_this = 0; 00782 00783 /* Determine whether we should code this trigger */ 00784 if( 00785 p->op==op && 00786 p->tr_tm==tr_tm && 00787 (p->pSchema==p->pTabSchema || p->pSchema==db->aDb[1].pSchema) && 00788 (op!=TK_UPDATE||!p->pColumns||checkColumnOverLap(p->pColumns,pChanges)) 00789 ){ 00790 TriggerStack *pS; /* Pointer to trigger-stack entry */ 00791 for(pS=pParse->trigStack; pS && p!=pS->pTrigger; pS=pS->pNext){} 00792 if( !pS ){ 00793 fire_this = 1; 00794 } 00795 #if 0 /* Give no warning for recursive triggers. Just do not do them */ 00796 else{ 00797 sqlite3ErrorMsg(pParse, "recursive triggers not supported (%s)", 00798 p->name); 00799 return SQLITE_ERROR; 00800 } 00801 #endif 00802 } 00803 00804 if( fire_this ){ 00805 int endTrigger; 00806 Expr * whenExpr; 00807 AuthContext sContext; 00808 NameContext sNC; 00809 00810 #ifndef SQLITE_OMIT_TRACE 00811 sqlite3VdbeAddOp4(pParse->pVdbe, OP_Trace, 0, 0, 0, 00812 sqlite3MPrintf(db, "-- TRIGGER %s", p->name), 00813 P4_DYNAMIC); 00814 #endif 00815 memset(&sNC, 0, sizeof(sNC)); 00816 sNC.pParse = pParse; 00817 00818 /* Push an entry on to the trigger stack */ 00819 trigStackEntry.pTrigger = p; 00820 trigStackEntry.newIdx = newIdx; 00821 trigStackEntry.oldIdx = oldIdx; 00822 trigStackEntry.pTab = pTab; 00823 trigStackEntry.pNext = pParse->trigStack; 00824 trigStackEntry.ignoreJump = ignoreJump; 00825 pParse->trigStack = &trigStackEntry; 00826 sqlite3AuthContextPush(pParse, &sContext, p->name); 00827 00828 /* code the WHEN clause */ 00829 endTrigger = sqlite3VdbeMakeLabel(pParse->pVdbe); 00830 whenExpr = sqlite3ExprDup(db, p->pWhen); 00831 if( db->mallocFailed || sqlite3ResolveExprNames(&sNC, whenExpr) ){ 00832 pParse->trigStack = trigStackEntry.pNext; 00833 sqlite3ExprDelete(db, whenExpr); 00834 return 1; 00835 } 00836 sqlite3ExprIfFalse(pParse, whenExpr, endTrigger, SQLITE_JUMPIFNULL); 00837 sqlite3ExprDelete(db, whenExpr); 00838 00839 codeTriggerProgram(pParse, p->step_list, orconf); 00840 00841 /* Pop the entry off the trigger stack */ 00842 pParse->trigStack = trigStackEntry.pNext; 00843 sqlite3AuthContextPop(&sContext); 00844 00845 sqlite3VdbeResolveLabel(pParse->pVdbe, endTrigger); 00846 } 00847 } 00848 if( piOldColMask ) *piOldColMask |= trigStackEntry.oldColMask; 00849 if( piNewColMask ) *piNewColMask |= trigStackEntry.newColMask; 00850 return 0; 00851 } 00852 #endif /* !defined(SQLITE_OMIT_TRIGGER) */
ContextLogger2—ContextLogger2 Logger Daemon Internals—Generated on Mon May 2 13:49:56 2011 by Doxygen 1.6.1