/* ** Duplicate an Upsert object. */ Upsert *sqlite3UpsertDup(sqlite3 *db, Upsert *p){ if( p==0 ) return 0; return sqlite3UpsertNew(db, sqlite3ExprListDup(db, p->pUpsertTarget, 0), sqlite3ExprDup(db, p->pUpsertTargetWhere, 0), sqlite3ExprListDup(db, p->pUpsertSet, 0), sqlite3ExprDup(db, p->pUpsertWhere, 0) ); }
/* ** Make a copy of all components of the given trigger step. This has ** the effect of copying all Expr.token.z values into memory obtained ** from sqliteMalloc(). As initially created, the Expr.token.z values ** all point to the input string that was fed to the parser. But that ** string is ephemeral - it will go away as soon as the sqlite3_exec() ** call that started the parser exits. This routine makes a persistent ** copy of all the Expr.token.z strings so that the TriggerStep structure ** will be valid even after the sqlite3_exec() call returns. */ static void sqlitePersistTriggerStep(TriggerStep *p){ if( p->target.z ){ p->target.z = sqliteStrNDup(p->target.z, p->target.n); p->target.dyn = 1; } if( p->pSelect ){ Select *pNew = sqlite3SelectDup(p->pSelect); sqlite3SelectDelete(p->pSelect); p->pSelect = pNew; } if( p->pWhere ){ Expr *pNew = sqlite3ExprDup(p->pWhere); sqlite3ExprDelete(p->pWhere); p->pWhere = pNew; } if( p->pExprList ){ ExprList *pNew = sqlite3ExprListDup(p->pExprList); sqlite3ExprListDelete(p->pExprList); p->pExprList = pNew; } if( p->pIdList ){ IdList *pNew = sqlite3IdListDup(p->pIdList); sqlite3IdListDelete(p->pIdList); p->pIdList = pNew; } }
/* ** Build a trigger step out of an INSERT statement. Return a pointer ** to the new trigger step. ** ** The parser calls this routine when it sees an INSERT inside the ** body of a trigger. */ SQLITE_PRIVATE TriggerStep *sqlite3TriggerInsertStep( sqlite3 *db, /* The database connection */ Token *pTableName, /* Name of the table into which we insert */ IdList *pColumn, /* List of columns in pTableName to insert into */ ExprList *pEList, /* The VALUE clause: a list of values to be inserted */ Select *pSelect, /* A SELECT statement that supplies values */ u8 orconf /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */ ){ TriggerStep *pTriggerStep; assert(pEList == 0 || pSelect == 0); assert(pEList != 0 || pSelect != 0 || db->mallocFailed); pTriggerStep = triggerStepAllocate(db, TK_INSERT, pTableName); if( pTriggerStep ){ pTriggerStep->pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE); pTriggerStep->pIdList = pColumn; pTriggerStep->pExprList = sqlite3ExprListDup(db, pEList, EXPRDUP_REDUCE); pTriggerStep->orconf = orconf; }else{ sqlite3IdListDelete(db, pColumn); } sqlite3ExprListDelete(db, pEList); sqlite3SelectDelete(db, pSelect); return pTriggerStep; }
/* ** Construct a trigger step that implements an UPDATE statement and return ** a pointer to that trigger step. The parser calls this routine when it ** sees an UPDATE statement inside the body of a CREATE TRIGGER. */ TriggerStep *sqlite3TriggerUpdateStep( Parse *pParse, /* Parser */ Token *pTableName, /* Name of the table to be updated */ ExprList *pEList, /* The SET clause: list of column and new values */ Expr *pWhere, /* The WHERE clause */ u8 orconf, /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */ const char *zStart, /* Start of SQL text */ const char *zEnd /* End of SQL text */ ){ sqlite3 *db = pParse->db; TriggerStep *pTriggerStep; pTriggerStep = triggerStepAllocate(pParse, TK_UPDATE, pTableName,zStart,zEnd); if( pTriggerStep ){ if( IN_RENAME_OBJECT ){ pTriggerStep->pExprList = pEList; pTriggerStep->pWhere = pWhere; pEList = 0; pWhere = 0; }else{ pTriggerStep->pExprList = sqlite3ExprListDup(db, pEList, EXPRDUP_REDUCE); pTriggerStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE); } pTriggerStep->orconf = orconf; } sqlite3ExprListDelete(db, pEList); sqlite3ExprDelete(db, pWhere); return pTriggerStep; }
/* ** Make a copy of all components of the given trigger step. This has ** the effect of copying all Expr.token.z values into memory obtained ** from sqlite3_malloc(). As initially created, the Expr.token.z values ** all point to the input string that was fed to the parser. But that ** string is ephemeral - it will go away as soon as the sqlite3_exec() ** call that started the parser exits. This routine makes a persistent ** copy of all the Expr.token.z strings so that the TriggerStep structure ** will be valid even after the sqlite3_exec() call returns. */ static void sqlitePersistTriggerStep(sqlite3 *db, TriggerStep *p){ if( p->target.z ){ p->target.z = (u8*)sqlite3DbStrNDup(db, (char*)p->target.z, p->target.n); p->target.dyn = 1; } if( p->pSelect ){ Select *pNew = sqlite3SelectDup(db, p->pSelect); sqlite3SelectDelete(db, p->pSelect); p->pSelect = pNew; } if( p->pWhere ){ Expr *pNew = sqlite3ExprDup(db, p->pWhere); sqlite3ExprDelete(db, p->pWhere); p->pWhere = pNew; } if( p->pExprList ){ ExprList *pNew = sqlite3ExprListDup(db, p->pExprList); sqlite3ExprListDelete(db, p->pExprList); p->pExprList = pNew; } if( p->pIdList ){ IdList *pNew = sqlite3IdListDup(db, p->pIdList); sqlite3IdListDelete(db, p->pIdList); p->pIdList = pNew; } }
/* ** Construct a trigger step that implements an UPDATE statement and return ** a pointer to that trigger step. The parser calls this routine when it ** sees an UPDATE statement inside the body of a CREATE TRIGGER. */ SQLITE_PRIVATE TriggerStep *sqlite3TriggerUpdateStep( sqlite3 *db, /* The database connection */ Token *pTableName, /* Name of the table to be updated */ ExprList *pEList, /* The SET clause: list of column and new values */ Expr *pWhere, /* The WHERE clause */ u8 orconf /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */ ){ TriggerStep *pTriggerStep; pTriggerStep = triggerStepAllocate(db, TK_UPDATE, pTableName); if( pTriggerStep ){ pTriggerStep->pExprList = sqlite3ExprListDup(db, pEList, EXPRDUP_REDUCE); pTriggerStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE); pTriggerStep->orconf = orconf; } sqlite3ExprListDelete(db, pEList); sqlite3ExprDelete(db, pWhere); return pTriggerStep; }
/* ** Generate VDBE code for zero or more statements inside the body of a ** trigger. */ static int codeTriggerProgram( Parse *pParse, /* The parser context */ TriggerStep *pStepList, /* List of statements inside the trigger body */ int orconfin /* Conflict algorithm. (OE_Abort, etc) */ ){ TriggerStep * pTriggerStep = pStepList; int orconf; while( pTriggerStep ){ int saveNTab = pParse->nTab; orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin; pParse->trigStack->orconf = orconf; switch( pTriggerStep->op ){ case TK_SELECT: { Select * ss = sqlite3SelectDup(pTriggerStep->pSelect); assert(ss); assert(ss->pSrc); sqlite3Select(pParse, ss, SRT_Discard, 0, 0, 0, 0, 0); sqlite3SelectDelete(ss); break; } case TK_UPDATE: { SrcList *pSrc; pSrc = targetSrcList(pParse, pTriggerStep); sqlite3VdbeAddOp(pParse->pVdbe, OP_ResetCount, 0, 0); sqlite3VdbeAddOp(pParse->pVdbe, OP_ListPush, 0, 0); sqlite3Update(pParse, pSrc, sqlite3ExprListDup(pTriggerStep->pExprList), sqlite3ExprDup(pTriggerStep->pWhere), orconf); sqlite3VdbeAddOp(pParse->pVdbe, OP_ListPop, 0, 0); sqlite3VdbeAddOp(pParse->pVdbe, OP_ResetCount, 1, 0); break; } case TK_INSERT: { SrcList *pSrc; pSrc = targetSrcList(pParse, pTriggerStep); sqlite3VdbeAddOp(pParse->pVdbe, OP_ResetCount, 0, 0); sqlite3Insert(pParse, pSrc, sqlite3ExprListDup(pTriggerStep->pExprList), sqlite3SelectDup(pTriggerStep->pSelect), sqlite3IdListDup(pTriggerStep->pIdList), orconf); sqlite3VdbeAddOp(pParse->pVdbe, OP_ResetCount, 1, 0); break; } case TK_DELETE: { SrcList *pSrc; sqlite3VdbeAddOp(pParse->pVdbe, OP_ResetCount, 0, 0); sqlite3VdbeAddOp(pParse->pVdbe, OP_ListPush, 0, 0); pSrc = targetSrcList(pParse, pTriggerStep); sqlite3DeleteFrom(pParse, pSrc, sqlite3ExprDup(pTriggerStep->pWhere)); sqlite3VdbeAddOp(pParse->pVdbe, OP_ListPop, 0, 0); sqlite3VdbeAddOp(pParse->pVdbe, OP_ResetCount, 1, 0); break; } default: assert(0); } pParse->nTab = saveNTab; pTriggerStep = pTriggerStep->pNext; } return 0; }
/* ** Generate an expression tree to implement the WHERE, ORDER BY, ** and LIMIT/OFFSET portion of DELETE and UPDATE statements. ** ** DELETE FROM table_wxyz WHERE a<5 ORDER BY a LIMIT 1; ** \__________________________/ ** pLimitWhere (pInClause) */ Expr *sqlite3LimitWhere( Parse *pParse, /* The parser context */ SrcList *pSrc, /* the FROM clause -- which tables to scan */ Expr *pWhere, /* The WHERE clause. May be null */ ExprList *pOrderBy, /* The ORDER BY clause. May be null */ Expr *pLimit, /* The LIMIT clause. May be null */ char *zStmtType /* Either DELETE or UPDATE. For err msgs. */ ){ sqlite3 *db = pParse->db; Expr *pLhs = NULL; /* LHS of IN(SELECT...) operator */ Expr *pInClause = NULL; /* WHERE rowid IN ( select ) */ ExprList *pEList = NULL; /* Expression list contaning only pSelectRowid */ SrcList *pSelectSrc = NULL; /* SELECT rowid FROM x ... (dup of pSrc) */ Select *pSelect = NULL; /* Complete SELECT tree */ Table *pTab; /* Check that there isn't an ORDER BY without a LIMIT clause. */ if( pOrderBy && pLimit==0 ) { sqlite3ErrorMsg(pParse, "ORDER BY without LIMIT on %s", zStmtType); sqlite3ExprDelete(pParse->db, pWhere); sqlite3ExprListDelete(pParse->db, pOrderBy); return 0; } /* We only need to generate a select expression if there ** is a limit/offset term to enforce. */ if( pLimit == 0 ) { return pWhere; } /* Generate a select expression tree to enforce the limit/offset ** term for the DELETE or UPDATE statement. For example: ** DELETE FROM table_a WHERE col1=1 ORDER BY col2 LIMIT 1 OFFSET 1 ** becomes: ** DELETE FROM table_a WHERE rowid IN ( ** SELECT rowid FROM table_a WHERE col1=1 ORDER BY col2 LIMIT 1 OFFSET 1 ** ); */ pTab = pSrc->a[0].pTab; if( HasRowid(pTab) ){ pLhs = sqlite3PExpr(pParse, TK_ROW, 0, 0); pEList = sqlite3ExprListAppend( pParse, 0, sqlite3PExpr(pParse, TK_ROW, 0, 0) ); }else{ Index *pPk = sqlite3PrimaryKeyIndex(pTab); if( pPk->nKeyCol==1 ){ const char *zName = pTab->aCol[pPk->aiColumn[0]].zName; pLhs = sqlite3Expr(db, TK_ID, zName); pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ID, zName)); }else{ int i; for(i=0; i<pPk->nKeyCol; i++){ Expr *p = sqlite3Expr(db, TK_ID, pTab->aCol[pPk->aiColumn[i]].zName); pEList = sqlite3ExprListAppend(pParse, pEList, p); } pLhs = sqlite3PExpr(pParse, TK_VECTOR, 0, 0); if( pLhs ){ pLhs->x.pList = sqlite3ExprListDup(db, pEList, 0); } } } /* duplicate the FROM clause as it is needed by both the DELETE/UPDATE tree ** and the SELECT subtree. */ pSrc->a[0].pTab = 0; pSelectSrc = sqlite3SrcListDup(pParse->db, pSrc, 0); pSrc->a[0].pTab = pTab; pSrc->a[0].pIBIndex = 0; /* generate the SELECT expression tree. */ pSelect = sqlite3SelectNew(pParse, pEList, pSelectSrc, pWhere, 0 ,0, pOrderBy,0,pLimit ); /* now generate the new WHERE rowid IN clause for the DELETE/UDPATE */ pInClause = sqlite3PExpr(pParse, TK_IN, pLhs, 0); sqlite3PExprAddSelect(pParse, pInClause, pSelect); return pInClause; }
/* ** Generate VDBE code for the statements inside the body of a single ** trigger. */ static int codeTriggerProgram( Parse *pParse, /* The parser context */ TriggerStep *pStepList, /* List of statements inside the trigger body */ int orconf /* Conflict algorithm. (OE_Abort, etc) */ ){ TriggerStep *pStep; Vdbe *v = pParse->pVdbe; sqlite3 *db = pParse->db; assert( pParse->pTriggerTab && pParse->pToplevel ); assert( pStepList ); assert( v!=0 ); for(pStep=pStepList; pStep; pStep=pStep->pNext){ /* Figure out the ON CONFLICT policy that will be used for this step ** of the trigger program. If the statement that caused this trigger ** to fire had an explicit ON CONFLICT, then use it. Otherwise, use ** the ON CONFLICT policy that was specified as part of the trigger ** step statement. Example: ** ** CREATE TRIGGER AFTER INSERT ON t1 BEGIN; ** INSERT OR REPLACE INTO t2 VALUES(new.a, new.b); ** END; ** ** INSERT INTO t1 ... ; -- insert into t2 uses REPLACE policy ** INSERT OR IGNORE INTO t1 ... ; -- insert into t2 uses IGNORE policy */ pParse->eOrconf = (orconf==OE_Default)?pStep->orconf:(u8)orconf; /* Clear the cookieGoto flag. When coding triggers, the cookieGoto ** variable is used as a flag to indicate to sqlite3ExprCodeConstants() ** that it is not safe to refactor constants (this happens after the ** start of the first loop in the SQL statement is coded - at that ** point code may be conditionally executed, so it is no longer safe to ** initialize constant register values). */ assert( pParse->cookieGoto==0 || pParse->cookieGoto==-1 ); pParse->cookieGoto = 0; switch( pStep->op ){ case TK_UPDATE: { sqlite3Update(pParse, targetSrcList(pParse, pStep), sqlite3ExprListDup(db, pStep->pExprList, 0), sqlite3ExprDup(db, pStep->pWhere, 0), pParse->eOrconf ); break; } case TK_INSERT: { sqlite3Insert(pParse, targetSrcList(pParse, pStep), sqlite3ExprListDup(db, pStep->pExprList, 0), sqlite3SelectDup(db, pStep->pSelect, 0), sqlite3IdListDup(db, pStep->pIdList), pParse->eOrconf ); break; } case TK_DELETE: { sqlite3DeleteFrom(pParse, targetSrcList(pParse, pStep), sqlite3ExprDup(db, pStep->pWhere, 0) ); break; } default: assert( pStep->op==TK_SELECT ); { SelectDest sDest; Select *pSelect = sqlite3SelectDup(db, pStep->pSelect, 0); sqlite3SelectDestInit(&sDest, SRT_Discard, 0); sqlite3Select(pParse, pSelect, &sDest); sqlite3SelectDelete(db, pSelect); break; } } if( pStep->op!=TK_SELECT ){ sqlite3VdbeAddOp0(v, OP_ResetCount); } } return 0; }
/* ** Generate VDBE code for zero or more statements inside the body of a ** trigger. */ static int codeTriggerProgram( Parse *pParse, /* The parser context */ TriggerStep *pStepList, /* List of statements inside the trigger body */ int orconfin /* Conflict algorithm. (OE_Abort, etc) */ ){ TriggerStep * pTriggerStep = pStepList; int orconf; Vdbe *v = pParse->pVdbe; sqlite3 *db = pParse->db; assert( pTriggerStep!=0 ); assert( v!=0 ); sqlite3VdbeAddOp(v, OP_ContextPush, 0, 0); VdbeComment((v, "# begin trigger %s", pStepList->pTrig->name)); while( pTriggerStep ){ orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin; pParse->trigStack->orconf = orconf; switch( pTriggerStep->op ){ case TK_SELECT: { Select *ss = sqlite3SelectDup(db, pTriggerStep->pSelect); if( ss ){ sqlite3SelectResolve(pParse, ss, 0); sqlite3Select(pParse, ss, SRT_Discard, 0, 0, 0, 0, 0); sqlite3SelectDelete(ss); } break; } case TK_UPDATE: { SrcList *pSrc; pSrc = targetSrcList(pParse, pTriggerStep); sqlite3VdbeAddOp(v, OP_ResetCount, 0, 0); sqlite3Update(pParse, pSrc, sqlite3ExprListDup(db, pTriggerStep->pExprList), sqlite3ExprDup(db, pTriggerStep->pWhere), orconf); sqlite3VdbeAddOp(v, OP_ResetCount, 1, 0); break; } case TK_INSERT: { SrcList *pSrc; pSrc = targetSrcList(pParse, pTriggerStep); sqlite3VdbeAddOp(v, OP_ResetCount, 0, 0); sqlite3Insert(pParse, pSrc, sqlite3ExprListDup(db, pTriggerStep->pExprList), sqlite3SelectDup(db, pTriggerStep->pSelect), sqlite3IdListDup(db, pTriggerStep->pIdList), orconf); sqlite3VdbeAddOp(v, OP_ResetCount, 1, 0); break; } case TK_DELETE: { SrcList *pSrc; sqlite3VdbeAddOp(v, OP_ResetCount, 0, 0); pSrc = targetSrcList(pParse, pTriggerStep); sqlite3DeleteFrom(pParse, pSrc, sqlite3ExprDup(db, pTriggerStep->pWhere)); sqlite3VdbeAddOp(v, OP_ResetCount, 1, 0); break; } default: assert(0); } pTriggerStep = pTriggerStep->pNext; } sqlite3VdbeAddOp(v, OP_ContextPop, 0, 0); VdbeComment((v, "# end trigger %s", pStepList->pTrig->name)); return 0; }
/* ** Generate VDBE code for the statements inside the body of a single ** trigger. */ static int codeTriggerProgram( Parse *pParse, /* The parser context */ TriggerStep *pStepList, /* List of statements inside the trigger body */ int orconf /* Conflict algorithm. (OE_Abort, etc) */ ){ TriggerStep *pStep; Vdbe *v = pParse->pVdbe; sqlite3 *db = pParse->db; assert( pParse->pTriggerTab && pParse->pToplevel ); assert( pStepList ); assert( v!=0 ); for(pStep=pStepList; pStep; pStep=pStep->pNext){ /* Figure out the ON CONFLICT policy that will be used for this step ** of the trigger program. If the statement that caused this trigger ** to fire had an explicit ON CONFLICT, then use it. Otherwise, use ** the ON CONFLICT policy that was specified as part of the trigger ** step statement. Example: ** ** CREATE TRIGGER AFTER INSERT ON t1 BEGIN; ** INSERT OR REPLACE INTO t2 VALUES(new.a, new.b); ** END; ** ** INSERT INTO t1 ... ; -- insert into t2 uses REPLACE policy ** INSERT OR IGNORE INTO t1 ... ; -- insert into t2 uses IGNORE policy */ pParse->eOrconf = (orconf==OE_Default)?pStep->orconf:(u8)orconf; assert( pParse->okConstFactor==0 ); switch( pStep->op ){ case TK_UPDATE: { sqlite3Update(pParse, targetSrcList(pParse, pStep), sqlite3ExprListDup(db, pStep->pExprList, 0), sqlite3ExprDup(db, pStep->pWhere, 0), pParse->eOrconf ); break; } case TK_INSERT: { sqlite3Insert(pParse, targetSrcList(pParse, pStep), sqlite3SelectDup(db, pStep->pSelect, 0), sqlite3IdListDup(db, pStep->pIdList), pParse->eOrconf ); break; } case TK_DELETE: { sqlite3DeleteFrom(pParse, targetSrcList(pParse, pStep), sqlite3ExprDup(db, pStep->pWhere, 0) ); break; } default: assert( pStep->op==TK_SELECT ); { SelectDest sDest; Select *pSelect = sqlite3SelectDup(db, pStep->pSelect, 0); sqlite3SelectDestInit(&sDest, SRT_Discard, 0); sqlite3Select(pParse, pSelect, &sDest); sqlite3SelectDelete(db, pSelect); break; } } if( pStep->op!=TK_SELECT ){ sqlite3VdbeAddOp0(v, OP_ResetCount); } } return 0; }
/* ** This function is called when an UPDATE or DELETE operation is being ** compiled on table pTab, which is the parent table of foreign-key pFKey. ** If the current operation is an UPDATE, then the pChanges parameter is ** passed a pointer to the list of columns being modified. If it is a ** DELETE, pChanges is passed a NULL pointer. ** ** It returns a pointer to a Trigger structure containing a trigger ** equivalent to the ON UPDATE or ON DELETE action specified by pFKey. ** If the action is "NO ACTION" or "RESTRICT", then a NULL pointer is ** returned (these actions require no special handling by the triggers ** sub-system, code for them is created by fkScanChildren()). ** ** For example, if pFKey is the foreign key and pTab is table "p" in ** the following schema: ** ** CREATE TABLE p(pk PRIMARY KEY); ** CREATE TABLE c(ck REFERENCES p ON DELETE CASCADE); ** ** then the returned trigger structure is equivalent to: ** ** CREATE TRIGGER ... DELETE ON p BEGIN ** DELETE FROM c WHERE ck = old.pk; ** END; ** ** The returned pointer is cached as part of the foreign key object. It ** is eventually freed along with the rest of the foreign key object by ** sqlite3FkDelete(). */ static Trigger *fkActionTrigger( Parse *pParse, /* Parse context */ Table *pTab, /* Table being updated or deleted from */ FKey *pFKey, /* Foreign key to get action for */ ExprList *pChanges /* Change-list for UPDATE, NULL for DELETE */ ){ sqlite3 *db = pParse->db; /* Database handle */ int action; /* One of OE_None, OE_Cascade etc. */ Trigger *pTrigger; /* Trigger definition to return */ int iAction = (pChanges!=0); /* 1 for UPDATE, 0 for DELETE */ action = pFKey->aAction[iAction]; pTrigger = pFKey->apTrigger[iAction]; if( action!=OE_None && !pTrigger ){ u8 enableLookaside; /* Copy of db->lookaside.bEnabled */ char const *zFrom; /* Name of child table */ int nFrom; /* Length in bytes of zFrom */ Index *pIdx = 0; /* Parent key index for this FK */ int *aiCol = 0; /* child table cols -> parent key cols */ TriggerStep *pStep = 0; /* First (only) step of trigger program */ Expr *pWhere = 0; /* WHERE clause of trigger step */ ExprList *pList = 0; /* Changes list if ON UPDATE CASCADE */ Select *pSelect = 0; /* If RESTRICT, "SELECT RAISE(...)" */ int i; /* Iterator variable */ Expr *pWhen = 0; /* WHEN clause for the trigger */ if( locateFkeyIndex(pParse, pTab, pFKey, &pIdx, &aiCol) ) return 0; assert( aiCol || pFKey->nCol==1 ); for(i=0; i<pFKey->nCol; i++){ Token tOld = { "old", 3 }; /* Literal "old" token */ Token tNew = { "new", 3 }; /* Literal "new" token */ Token tFromCol; /* Name of column in child table */ Token tToCol; /* Name of column in parent table */ int iFromCol; /* Idx of column in child table */ Expr *pEq; /* tFromCol = OLD.tToCol */ iFromCol = aiCol ? aiCol[i] : pFKey->aCol[0].iFrom; assert( iFromCol>=0 ); tToCol.z = pIdx ? pTab->aCol[pIdx->aiColumn[i]].zName : "oid"; tFromCol.z = pFKey->pFrom->aCol[iFromCol].zName; tToCol.n = sqlite3Strlen30(tToCol.z); tFromCol.n = sqlite3Strlen30(tFromCol.z); /* Create the expression "OLD.zToCol = zFromCol". It is important ** that the "OLD.zToCol" term is on the LHS of the = operator, so ** that the affinity and collation sequence associated with the ** parent table are used for the comparison. */ pEq = sqlite3PExpr(pParse, TK_EQ, sqlite3PExpr(pParse, TK_DOT, sqlite3PExpr(pParse, TK_ID, 0, 0, &tOld), sqlite3PExpr(pParse, TK_ID, 0, 0, &tToCol) , 0), sqlite3PExpr(pParse, TK_ID, 0, 0, &tFromCol) , 0); pWhere = sqlite3ExprAnd(db, pWhere, pEq); /* For ON UPDATE, construct the next term of the WHEN clause. ** The final WHEN clause will be like this: ** ** WHEN NOT(old.col1 IS new.col1 AND ... AND old.colN IS new.colN) */ if( pChanges ){ pEq = sqlite3PExpr(pParse, TK_IS, sqlite3PExpr(pParse, TK_DOT, sqlite3PExpr(pParse, TK_ID, 0, 0, &tOld), sqlite3PExpr(pParse, TK_ID, 0, 0, &tToCol), 0), sqlite3PExpr(pParse, TK_DOT, sqlite3PExpr(pParse, TK_ID, 0, 0, &tNew), sqlite3PExpr(pParse, TK_ID, 0, 0, &tToCol), 0), 0); pWhen = sqlite3ExprAnd(db, pWhen, pEq); } if( action!=OE_Restrict && (action!=OE_Cascade || pChanges) ){ Expr *pNew; if( action==OE_Cascade ){ pNew = sqlite3PExpr(pParse, TK_DOT, sqlite3PExpr(pParse, TK_ID, 0, 0, &tNew), sqlite3PExpr(pParse, TK_ID, 0, 0, &tToCol) , 0); }else if( action==OE_SetDflt ){ Expr *pDflt = pFKey->pFrom->aCol[iFromCol].pDflt; if( pDflt ){ pNew = sqlite3ExprDup(db, pDflt, 0); }else{ pNew = sqlite3PExpr(pParse, TK_NULL, 0, 0, 0); } }else{ pNew = sqlite3PExpr(pParse, TK_NULL, 0, 0, 0); } pList = sqlite3ExprListAppend(pParse, pList, pNew); sqlite3ExprListSetName(pParse, pList, &tFromCol, 0); } } sqlite3DbFree(db, aiCol); zFrom = pFKey->pFrom->zName; nFrom = sqlite3Strlen30(zFrom); if( action==OE_Restrict ){ Token tFrom; Expr *pRaise; tFrom.z = zFrom; tFrom.n = nFrom; pRaise = sqlite3Expr(db, TK_RAISE, "foreign key constraint failed"); if( pRaise ){ pRaise->affinity = OE_Abort; } pSelect = sqlite3SelectNew(pParse, sqlite3ExprListAppend(pParse, 0, pRaise), sqlite3SrcListAppend(db, 0, &tFrom, 0), pWhere, 0, 0, 0, 0, 0, 0 ); pWhere = 0; } /* Disable lookaside memory allocation */ enableLookaside = db->lookaside.bEnabled; db->lookaside.bEnabled = 0; pTrigger = (Trigger *)sqlite3DbMallocZero(db, sizeof(Trigger) + /* struct Trigger */ sizeof(TriggerStep) + /* Single step in trigger program */ nFrom + 1 /* Space for pStep->target.z */ ); if( pTrigger ){ pStep = pTrigger->step_list = (TriggerStep *)&pTrigger[1]; pStep->target.z = (char *)&pStep[1]; pStep->target.n = nFrom; memcpy((char *)pStep->target.z, zFrom, nFrom); pStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE); pStep->pExprList = sqlite3ExprListDup(db, pList, EXPRDUP_REDUCE); pStep->pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE); if( pWhen ){ pWhen = sqlite3PExpr(pParse, TK_NOT, pWhen, 0, 0); pTrigger->pWhen = sqlite3ExprDup(db, pWhen, EXPRDUP_REDUCE); } } /* Re-enable the lookaside buffer, if it was disabled earlier. */ db->lookaside.bEnabled = enableLookaside; sqlite3ExprDelete(db, pWhere); sqlite3ExprDelete(db, pWhen); sqlite3ExprListDelete(db, pList); sqlite3SelectDelete(db, pSelect); if( db->mallocFailed==1 ){ fkTriggerDelete(db, pTrigger); return 0; } assert( pStep!=0 ); switch( action ){ case OE_Restrict: pStep->op = TK_SELECT; break; case OE_Cascade: if( !pChanges ){ pStep->op = TK_DELETE; break; } default: pStep->op = TK_UPDATE; } pStep->pTrig = pTrigger; pTrigger->pSchema = pTab->pSchema; pTrigger->pTabSchema = pTab->pSchema; pFKey->apTrigger[iAction] = pTrigger; pTrigger->op = (pChanges ? TK_UPDATE : TK_DELETE); } return pTrigger; }