/*
** 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;
}
