/*
** 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 = sqliteSelectDup(pTriggerStep->pSelect);
assert(ss);
assert(ss->pSrc);
sqliteSelect(pParse, ss, SRT_Discard, 0, 0, 0, 0);
sqliteSelectDelete(ss);
break;
}
case TK_UPDATE: {
SrcList *pSrc;
pSrc = targetSrcList(pParse, pTriggerStep);
sqliteVdbeAddOp(pParse->pVdbe, OP_ListPush, 0, 0);
sqliteUpdate(pParse, pSrc,
sqliteExprListDup(pTriggerStep->pExprList),
sqliteExprDup(pTriggerStep->pWhere), orconf);
sqliteVdbeAddOp(pParse->pVdbe, OP_ListPop, 0, 0);
break;
}
case TK_INSERT: {
SrcList *pSrc;
pSrc = targetSrcList(pParse, pTriggerStep);
sqliteInsert(pParse, pSrc,
sqliteExprListDup(pTriggerStep->pExprList),
sqliteSelectDup(pTriggerStep->pSelect),
sqliteIdListDup(pTriggerStep->pIdList), orconf);
break;
}
case TK_DELETE: {
SrcList *pSrc;
sqliteVdbeAddOp(pParse->pVdbe, OP_ListPush, 0, 0);
pSrc = targetSrcList(pParse, pTriggerStep);
sqliteDeleteFrom(pParse, pSrc, sqliteExprDup(pTriggerStep->pWhere));
sqliteVdbeAddOp(pParse->pVdbe, OP_ListPop, 0, 0);
break;
}
default:
assert(0);
}
pParse->nTab = saveNTab;
pTriggerStep = pTriggerStep->pNext;
}
return 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 sqlite_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 sqlite_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 = sqliteSelectDup(p->pSelect);
sqliteSelectDelete(p->pSelect);
p->pSelect = pNew;
}
if( p->pWhere ){
Expr *pNew = sqliteExprDup(p->pWhere);
sqliteExprDelete(p->pWhere);
p->pWhere = pNew;
}
if( p->pExprList ){
ExprList *pNew = sqliteExprListDup(p->pExprList);
sqliteExprListDelete(p->pExprList);
p->pExprList = pNew;
}
if( p->pIdList ){
IdList *pNew = sqliteIdListDup(p->pIdList);
sqliteIdListDelete(p->pIdList);
p->pIdList = pNew;
}
}
ExprList *sqliteExprListDup(ExprList *p){
ExprList *pNew;
struct ExprList_item *pItem;
int i;
if( p==0 ) return 0;
pNew = sqliteMalloc( sizeof(*pNew) );
if( pNew==0 ) return 0;
pNew->nExpr = pNew->nAlloc = p->nExpr;
pNew->a = pItem = sqliteMalloc( p->nExpr*sizeof(p->a[0]) );
for(i=0; pItem && i<p->nExpr; i++, pItem++){
Expr *pNewExpr, *pOldExpr;
pItem->pExpr = pNewExpr = sqliteExprDup(pOldExpr = p->a[i].pExpr);
if( pOldExpr->span.z!=0 && pNewExpr ){
/* Always make a copy of the span for top-level expressions in the
** expression list. The logic in SELECT processing that determines
** the names of columns in the result set needs this information */
sqliteTokenCopy(&pNewExpr->span, &pOldExpr->span);
}
assert( pNewExpr==0 || pNewExpr->span.z!=0
|| pOldExpr->span.z==0 || sqlite_malloc_failed );
pItem->zName = sqliteStrDup(p->a[i].zName);
pItem->sortOrder = p->a[i].sortOrder;
pItem->isAgg = p->a[i].isAgg;
pItem->done = 0;
}
return pNew;
}
/*
** The following group of routines make deep copies of expressions,
** expression lists, ID lists, and select statements. The copies can
** be deleted (by being passed to their respective ...Delete() routines)
** without effecting the originals.
**
** The expression list, ID, and source lists return by sqliteExprListDup(),
** sqliteIdListDup(), and sqliteSrcListDup() can not be further expanded
** by subsequent calls to sqlite*ListAppend() routines.
**
** Any tables that the SrcList might point to are not duplicated.
*/
Expr *sqliteExprDup(Expr *p){
Expr *pNew;
if( p==0 ) return 0;
pNew = sqliteMallocRaw( sizeof(*p) );
if( pNew==0 ) return 0;
memcpy(pNew, p, sizeof(*pNew));
if( p->token.z!=0 ){
pNew->token.z = sqliteStrDup(p->token.z);
pNew->token.dyn = 1;
}else{
assert( pNew->token.z==0 );
}
pNew->span.z = 0;
pNew->pLeft = sqliteExprDup(p->pLeft);
pNew->pRight = sqliteExprDup(p->pRight);
pNew->pList = sqliteExprListDup(p->pList);
pNew->pSelect = sqliteSelectDup(p->pSelect);
return pNew;
}
Select *sqliteSelectDup(Select *p){
Select *pNew;
if( p==0 ) return 0;
pNew = sqliteMallocRaw( sizeof(*p) );
if( pNew==0 ) return 0;
pNew->isDistinct = p->isDistinct;
pNew->pEList = sqliteExprListDup(p->pEList);
pNew->pSrc = sqliteSrcListDup(p->pSrc);
pNew->pWhere = sqliteExprDup(p->pWhere);
pNew->pGroupBy = sqliteExprListDup(p->pGroupBy);
pNew->pHaving = sqliteExprDup(p->pHaving);
pNew->pOrderBy = sqliteExprListDup(p->pOrderBy);
pNew->op = p->op;
pNew->pPrior = sqliteSelectDup(p->pPrior);
pNew->nLimit = p->nLimit;
pNew->nOffset = p->nOffset;
pNew->zSelect = 0;
pNew->iLimit = -1;
pNew->iOffset = -1;
return pNew;
}
SrcList *sqliteSrcListDup(SrcList *p){
SrcList *pNew;
int i;
int nByte;
if( p==0 ) return 0;
nByte = sizeof(*p) + (p->nSrc>0 ? sizeof(p->a[0]) * (p->nSrc-1) : 0);
pNew = sqliteMallocRaw( nByte );
if( pNew==0 ) return 0;
pNew->nSrc = pNew->nAlloc = p->nSrc;
for(i=0; i<p->nSrc; i++){
struct SrcList_item *pNewItem = &pNew->a[i];
struct SrcList_item *pOldItem = &p->a[i];
pNewItem->zDatabase = sqliteStrDup(pOldItem->zDatabase);
pNewItem->zName = sqliteStrDup(pOldItem->zName);
pNewItem->zAlias = sqliteStrDup(pOldItem->zAlias);
pNewItem->jointype = pOldItem->jointype;
pNewItem->iCursor = pOldItem->iCursor;
pNewItem->pTab = 0;
pNewItem->pSelect = sqliteSelectDup(pOldItem->pSelect);
pNewItem->pOn = sqliteExprDup(pOldItem->pOn);
pNewItem->pUsing = sqliteIdListDup(pOldItem->pUsing);
}
return pNew;
}
/*
** This is called to code FOR EACH ROW triggers.
**
** When the code that this function generates is executed, the following
** must be true:
**
** 1. No cursors may be open in the main database. (But newIdx and oldIdx
** can be indices of cursors in temporary tables. See below.)
**
** 2. If the triggers being coded are ON INSERT or ON UPDATE triggers, then
** a temporary vdbe cursor (index newIdx) must be open and pointing at
** a row containing values to be substituted for new.* expressions in the
** trigger program(s).
**
** 3. If the triggers being coded are ON DELETE or ON UPDATE triggers, then
** a temporary vdbe cursor (index oldIdx) must be open and pointing at
** a row containing values to be substituted for old.* expressions in the
** trigger program(s).
**
*/
int sqliteCodeRowTrigger(
Parse *pParse, /* Parse context */
int op, /* One of TK_UPDATE, TK_INSERT, TK_DELETE */
ExprList *pChanges, /* Changes list for any UPDATE OF triggers */
int tr_tm, /* One of TK_BEFORE, TK_AFTER */
Table *pTab, /* The table to code triggers from */
int newIdx, /* The indice of the "new" row to access */
int oldIdx, /* The indice of the "old" row to access */
int orconf, /* ON CONFLICT policy */
int ignoreJump /* Instruction to jump to for RAISE(IGNORE) */
){
Trigger * pTrigger;
TriggerStack * pTriggerStack;
assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE);
assert(tr_tm == TK_BEFORE || tr_tm == TK_AFTER );
assert(newIdx != -1 || oldIdx != -1);
pTrigger = pTab->pTrigger;
while( pTrigger ){
int fire_this = 0;
/* determine whether we should code this trigger */
if( pTrigger->op == op && pTrigger->tr_tm == tr_tm &&
pTrigger->foreach == TK_ROW ){
fire_this = 1;
pTriggerStack = pParse->trigStack;
while( pTriggerStack ){
if( pTriggerStack->pTrigger == pTrigger ){
fire_this = 0;
}
pTriggerStack = pTriggerStack->pNext;
}
if( op == TK_UPDATE && pTrigger->pColumns &&
!checkColumnOverLap(pTrigger->pColumns, pChanges) ){
fire_this = 0;
}
}
if( fire_this && (pTriggerStack = sqliteMalloc(sizeof(TriggerStack)))!=0 ){
int endTrigger;
SrcList dummyTablist;
Expr * whenExpr;
AuthContext sContext;
dummyTablist.nSrc = 0;
/* Push an entry on to the trigger stack */
pTriggerStack->pTrigger = pTrigger;
pTriggerStack->newIdx = newIdx;
pTriggerStack->oldIdx = oldIdx;
pTriggerStack->pTab = pTab;
pTriggerStack->pNext = pParse->trigStack;
pTriggerStack->ignoreJump = ignoreJump;
pParse->trigStack = pTriggerStack;
sqliteAuthContextPush(pParse, &sContext, pTrigger->name);
/* code the WHEN clause */
endTrigger = sqliteVdbeMakeLabel(pParse->pVdbe);
whenExpr = sqliteExprDup(pTrigger->pWhen);
if( sqliteExprResolveIds(pParse, &dummyTablist, 0, whenExpr) ){
pParse->trigStack = pParse->trigStack->pNext;
sqliteFree(pTriggerStack);
sqliteExprDelete(whenExpr);
return 1;
}
sqliteExprIfFalse(pParse, whenExpr, endTrigger, 1);
sqliteExprDelete(whenExpr);
sqliteVdbeAddOp(pParse->pVdbe, OP_ContextPush, 0, 0);
codeTriggerProgram(pParse, pTrigger->step_list, orconf);
sqliteVdbeAddOp(pParse->pVdbe, OP_ContextPop, 0, 0);
/* Pop the entry off the trigger stack */
pParse->trigStack = pParse->trigStack->pNext;
sqliteAuthContextPop(&sContext);
sqliteFree(pTriggerStack);
sqliteVdbeResolveLabel(pParse->pVdbe, endTrigger);
}
pTrigger = pTrigger->pNext;
}
return 0;
}
/*
** This is called by the parser when it sees a CREATE TRIGGER statement
** up to the point of the BEGIN before the trigger actions. A Trigger
** structure is generated based on the information available and stored
** in pParse->pNewTrigger. After the trigger actions have been parsed, the
** sqliteFinishTrigger() function is called to complete the trigger
** construction process.
*/
void sqliteBeginTrigger(
Parse *pParse, /* The parse context of the CREATE TRIGGER statement */
Token *pName, /* The name of the trigger */
int tr_tm, /* One of TK_BEFORE, TK_AFTER, TK_INSTEAD */
int op, /* One of TK_INSERT, TK_UPDATE, TK_DELETE */
IdList *pColumns, /* column list if this is an UPDATE OF trigger */
SrcList *pTableName,/* The name of the table/view the trigger applies to */
int foreach, /* One of TK_ROW or TK_STATEMENT */
Expr *pWhen, /* WHEN clause */
int isTemp /* True if the TEMPORARY keyword is present */
){
Trigger *nt;
Table *tab;
char *zName = 0; /* Name of the trigger */
sqlite *db = pParse->db;
int iDb; /* When database to store the trigger in */
DbFixer sFix;
/* Check that:
** 1. the trigger name does not already exist.
** 2. the table (or view) does exist in the same database as the trigger.
** 3. that we are not trying to create a trigger on the sqlite_master table
** 4. That we are not trying to create an INSTEAD OF trigger on a table.
** 5. That we are not trying to create a BEFORE or AFTER trigger on a view.
*/
if( sqlite_malloc_failed ) goto trigger_cleanup;
assert( pTableName->nSrc==1 );
if( db->init.busy
&& sqliteFixInit(&sFix, pParse, db->init.iDb, "trigger", pName)
&& sqliteFixSrcList(&sFix, pTableName)
){
goto trigger_cleanup;
}
tab = sqliteSrcListLookup(pParse, pTableName);
if( !tab ){
goto trigger_cleanup;
}
iDb = isTemp ? 1 : tab->iDb;
if( iDb>=2 && !db->init.busy ){
sqliteErrorMsg(pParse, "triggers may not be added to auxiliary "
"database %s", db->aDb[tab->iDb].zName);
goto trigger_cleanup;
}
zName = sqliteStrNDup(pName->z, pName->n);
sqliteDequote(zName);
if( sqliteHashFind(&(db->aDb[iDb].trigHash), zName,pName->n+1) ){
sqliteErrorMsg(pParse, "trigger %T already exists", pName);
goto trigger_cleanup;
}
if( sqliteStrNICmp(tab->zName, "sqlite_", 7)==0 ){
sqliteErrorMsg(pParse, "cannot create trigger on system table");
pParse->nErr++;
goto trigger_cleanup;
}
if( tab->pSelect && tr_tm != TK_INSTEAD ){
sqliteErrorMsg(pParse, "cannot create %s trigger on view: %S",
(tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName, 0);
goto trigger_cleanup;
}
if( !tab->pSelect && tr_tm == TK_INSTEAD ){
sqliteErrorMsg(pParse, "cannot create INSTEAD OF"
" trigger on table: %S", pTableName, 0);
goto trigger_cleanup;
}
#ifndef SQLITE_OMIT_AUTHORIZATION
{
int code = SQLITE_CREATE_TRIGGER;
const char *zDb = db->aDb[tab->iDb].zName;
const char *zDbTrig = isTemp ? db->aDb[1].zName : zDb;
if( tab->iDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER;
if( sqliteAuthCheck(pParse, code, zName, tab->zName, zDbTrig) ){
goto trigger_cleanup;
}
if( sqliteAuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(tab->iDb), 0, zDb)){
goto trigger_cleanup;
}
}
#endif
/* INSTEAD OF triggers can only appear on views and BEGIN triggers
** cannot appear on views. So we might as well translate every
** INSTEAD OF trigger into a BEFORE trigger. It simplifies code
** elsewhere.
*/
if (tr_tm == TK_INSTEAD){
tr_tm = TK_BEFORE;
}
/* Build the Trigger object */
nt = (Trigger*)sqliteMalloc(sizeof(Trigger));
if( nt==0 ) goto trigger_cleanup;
nt->name = zName;
zName = 0;
nt->table = sqliteStrDup(pTableName->a[0].zName);
if( sqlite_malloc_failed ) goto trigger_cleanup;
nt->iDb = iDb;
nt->iTabDb = tab->iDb;
nt->op = op;
nt->tr_tm = tr_tm;
nt->pWhen = sqliteExprDup(pWhen);
nt->pColumns = sqliteIdListDup(pColumns);
nt->foreach = foreach;
sqliteTokenCopy(&nt->nameToken,pName);
assert( pParse->pNewTrigger==0 );
pParse->pNewTrigger = nt;
trigger_cleanup:
sqliteFree(zName);
sqliteSrcListDelete(pTableName);
sqliteIdListDelete(pColumns);
sqliteExprDelete(pWhen);
}
/*
** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
** that name in the set of source tables in pSrcList and make the pExpr
** expression node refer back to that source column. The following changes
** are made to pExpr:
**
** pExpr->iDb Set the index in db->aDb[] of the database holding
** the table.
** pExpr->iTable Set to the cursor number for the table obtained
** from pSrcList.
** pExpr->iColumn Set to the column number within the table.
** pExpr->dataType Set to the appropriate data type for the column.
** pExpr->op Set to TK_COLUMN.
** pExpr->pLeft Any expression this points to is deleted
** pExpr->pRight Any expression this points to is deleted.
**
** The pDbToken is the name of the database (the "X"). This value may be
** NULL meaning that name is of the form Y.Z or Z. Any available database
** can be used. The pTableToken is the name of the table (the "Y"). This
** value can be NULL if pDbToken is also NULL. If pTableToken is NULL it
** means that the form of the name is Z and that columns from any table
** can be used.
**
** If the name cannot be resolved unambiguously, leave an error message
** in pParse and return non-zero. Return zero on success.
*/
static int lookupName(
Parse *pParse, /* The parsing context */
Token *pDbToken, /* Name of the database containing table, or NULL */
Token *pTableToken, /* Name of table containing column, or NULL */
Token *pColumnToken, /* Name of the column. */
SrcList *pSrcList, /* List of tables used to resolve column names */
ExprList *pEList, /* List of expressions used to resolve "AS" */
Expr *pExpr /* Make this EXPR node point to the selected column */
){
char *zDb = 0; /* Name of the database. The "X" in X.Y.Z */
char *zTab = 0; /* Name of the table. The "Y" in X.Y.Z or Y.Z */
char *zCol = 0; /* Name of the column. The "Z" */
int i, j; /* Loop counters */
int cnt = 0; /* Number of matching column names */
int cntTab = 0; /* Number of matching table names */
sqlite *db = pParse->db; /* The database */
assert( pColumnToken && pColumnToken->z ); /* The Z in X.Y.Z cannot be NULL */
if( pDbToken && pDbToken->z ){
zDb = sqliteStrNDup(pDbToken->z, pDbToken->n);
sqliteDequote(zDb);
}else{
zDb = 0;
}
if( pTableToken && pTableToken->z ){
zTab = sqliteStrNDup(pTableToken->z, pTableToken->n);
sqliteDequote(zTab);
}else{
assert( zDb==0 );
zTab = 0;
}
zCol = sqliteStrNDup(pColumnToken->z, pColumnToken->n);
sqliteDequote(zCol);
if( sqlite_malloc_failed ){
return 1; /* Leak memory (zDb and zTab) if malloc fails */
}
assert( zTab==0 || pEList==0 );
pExpr->iTable = -1;
for(i=0; i<pSrcList->nSrc; i++){
struct SrcList_item *pItem = &pSrcList->a[i];
Table *pTab = pItem->pTab;
Column *pCol;
if( pTab==0 ) continue;
assert( pTab->nCol>0 );
if( zTab ){
if( pItem->zAlias ){
char *zTabName = pItem->zAlias;
if( sqliteStrICmp(zTabName, zTab)!=0 ) continue;
}else{
char *zTabName = pTab->zName;
if( zTabName==0 || sqliteStrICmp(zTabName, zTab)!=0 ) continue;
if( zDb!=0 && sqliteStrICmp(db->aDb[pTab->iDb].zName, zDb)!=0 ){
continue;
}
}
}
if( 0==(cntTab++) ){
pExpr->iTable = pItem->iCursor;
pExpr->iDb = pTab->iDb;
}
for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
if( sqliteStrICmp(pCol->zName, zCol)==0 ){
cnt++;
pExpr->iTable = pItem->iCursor;
pExpr->iDb = pTab->iDb;
/* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
pExpr->iColumn = j==pTab->iPKey ? -1 : j;
pExpr->dataType = pCol->sortOrder & SQLITE_SO_TYPEMASK;
break;
}
}
}
/* If we have not already resolved the name, then maybe
** it is a new.* or old.* trigger argument reference
*/
if( zDb==0 && zTab!=0 && cnt==0 && pParse->trigStack!=0 ){
TriggerStack *pTriggerStack = pParse->trigStack;
Table *pTab = 0;
if( pTriggerStack->newIdx != -1 && sqliteStrICmp("new", zTab) == 0 ){
pExpr->iTable = pTriggerStack->newIdx;
assert( pTriggerStack->pTab );
pTab = pTriggerStack->pTab;
}else if( pTriggerStack->oldIdx != -1 && sqliteStrICmp("old", zTab) == 0 ){
pExpr->iTable = pTriggerStack->oldIdx;
assert( pTriggerStack->pTab );
pTab = pTriggerStack->pTab;
}
if( pTab ){
int j;
Column *pCol = pTab->aCol;
pExpr->iDb = pTab->iDb;
cntTab++;
for(j=0; j < pTab->nCol; j++, pCol++) {
if( sqliteStrICmp(pCol->zName, zCol)==0 ){
cnt++;
pExpr->iColumn = j==pTab->iPKey ? -1 : j;
pExpr->dataType = pCol->sortOrder & SQLITE_SO_TYPEMASK;
break;
}
}
}
}
/*
** Perhaps the name is a reference to the ROWID
*/
if( cnt==0 && cntTab==1 && sqliteIsRowid(zCol) ){
cnt = 1;
pExpr->iColumn = -1;
pExpr->dataType = SQLITE_SO_NUM;
}
/*
** If the input is of the form Z (not Y.Z or X.Y.Z) then the name Z
** might refer to an result-set alias. This happens, for example, when
** we are resolving names in the WHERE clause of the following command:
**
** SELECT a+b AS x FROM table WHERE x<10;
**
** In cases like this, replace pExpr with a copy of the expression that
** forms the result set entry ("a+b" in the example) and return immediately.
** Note that the expression in the result set should have already been
** resolved by the time the WHERE clause is resolved.
*/
if( cnt==0 && pEList!=0 ){
for(j=0; j<pEList->nExpr; j++){
char *zAs = pEList->a[j].zName;
if( zAs!=0 && sqliteStrICmp(zAs, zCol)==0 ){
assert( pExpr->pLeft==0 && pExpr->pRight==0 );
pExpr->op = TK_AS;
pExpr->iColumn = j;
pExpr->pLeft = sqliteExprDup(pEList->a[j].pExpr);
sqliteFree(zCol);
assert( zTab==0 && zDb==0 );
return 0;
}
}
}
/*
** If X and Y are NULL (in other words if only the column name Z is
** supplied) and the value of Z is enclosed in double-quotes, then
** Z is a string literal if it doesn't match any column names. In that
** case, we need to return right away and not make any changes to
** pExpr.
*/
if( cnt==0 && zTab==0 && pColumnToken->z[0]=='"' ){
sqliteFree(zCol);
return 0;
}
/*
** cnt==0 means there was not match. cnt>1 means there were two or
** more matches. Either way, we have an error.
*/
if( cnt!=1 ){
char *z = 0;
char *zErr;
zErr = cnt==0 ? "no such column: %s" : "ambiguous column name: %s";
if( zDb ){
sqliteSetString(&z, zDb, ".", zTab, ".", zCol, 0);
}else if( zTab ){
sqliteSetString(&z, zTab, ".", zCol, 0);
}else{
z = sqliteStrDup(zCol);
}
sqliteErrorMsg(pParse, zErr, z);
sqliteFree(z);
}
/* Clean up and return
*/
sqliteFree(zDb);
sqliteFree(zTab);
sqliteFree(zCol);
sqliteExprDelete(pExpr->pLeft);
pExpr->pLeft = 0;
sqliteExprDelete(pExpr->pRight);
pExpr->pRight = 0;
pExpr->op = TK_COLUMN;
sqliteAuthRead(pParse, pExpr, pSrcList);
return cnt!=1;
}