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Simplify the trigger logic for DELETE, INSERT, and UPDATE. (CVS 2157)

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FossilOrigin-Name: 8e164ab27771aced9a592ea4b7c27e9f184181a5
This commit is contained in:
drh
2004-12-07 14:06:13 +00:00
parent 81db88e630
commit dca7684141
8 changed files with 97 additions and 114 deletions
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53
src/trigger.c
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@@ -111,9 +111,7 @@ void sqlite3BeginTrigger(
}
/* Do not create a trigger on a system table */
if( (iDb!=1 && sqlite3StrICmp(pTab->zName, MASTER_NAME)==0) ||
(iDb==1 && sqlite3StrICmp(pTab->zName, TEMP_MASTER_NAME)==0)
){
if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){
sqlite3ErrorMsg(pParse, "cannot create trigger on system table");
pParse->nErr++;
goto trigger_cleanup;
@@ -167,7 +165,7 @@ void sqlite3BeginTrigger(
pTrigger->iDb = iDb;
pTrigger->iTabDb = pTab->iDb;
pTrigger->op = op;
pTrigger->tr_tm = tr_tm;
pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER;
pTrigger->pWhen = sqlite3ExprDup(pWhen);
pTrigger->pColumns = sqlite3IdListDup(pColumns);
pTrigger->foreach = foreach;
@@ -557,37 +555,37 @@ static int checkColumnOverLap(IdList *pIdList, ExprList *pEList){
}
/*
* Returns true if a trigger matching op, tr_tm and foreach that is NOT already
* on the Parse objects trigger-stack (to prevent recursive trigger firing) is
* found in the list specified as pTrigger.
*/
** Return a bit vector to indicate what kind of triggers exist for operation
** "op" on table pTab. If pChanges is not NULL then it is a list of columns
** that are being updated. Triggers only match if the ON clause of the
** trigger definition overlaps the set of columns being updated.
**
** The returned bit vector is some combination of TRIGGER_BEFORE and
** TRIGGER_AFTER.
*/
int sqlite3TriggersExist(
Parse *pParse, /* Used to check for recursive triggers */
Trigger *pTrigger, /* A list of triggers associated with a table */
Table *pTab, /* The table the contains the triggers */
int op, /* one of TK_DELETE, TK_INSERT, TK_UPDATE */
int tr_tm, /* one of TK_BEFORE, TK_AFTER */
int foreach, /* one of TK_ROW or TK_STATEMENT */
ExprList *pChanges /* Columns that change in an UPDATE statement */
){
Trigger * pTriggerCursor;
Trigger *pTrigger = pTab->pTrigger;
int mask = 0;
pTriggerCursor = pTrigger;
while( pTriggerCursor ){
if( pTriggerCursor->op == op &&
pTriggerCursor->tr_tm == tr_tm &&
pTriggerCursor->foreach == foreach &&
checkColumnOverLap(pTriggerCursor->pColumns, pChanges) ){
TriggerStack * ss;
while( pTrigger ){
if( pTrigger->op==op && checkColumnOverLap(pTrigger->pColumns, pChanges) ){
TriggerStack *ss;
ss = pParse->trigStack;
while( ss && ss->pTrigger != pTrigger ){
while( ss && ss->pTrigger!=pTab->pTrigger ){
ss = ss->pNext;
}
if( !ss )return 1;
if( ss==0 ){
mask |= pTrigger->tr_tm;
}
}
pTriggerCursor = pTriggerCursor->pNext;
pTrigger = pTrigger->pNext;
}
return 0;
return mask;
}
/*
@@ -713,7 +711,7 @@ int sqlite3CodeRowTrigger(
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 */
int tr_tm, /* One of TRIGGER_BEFORE, TRIGGER_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 */
@@ -725,7 +723,7 @@ int sqlite3CodeRowTrigger(
TriggerStack trigStackEntry;
assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE);
assert(tr_tm == TK_BEFORE || tr_tm == TK_AFTER );
assert(tr_tm == TRIGGER_BEFORE || tr_tm == TRIGGER_AFTER );
assert(newIdx != -1 || oldIdx != -1);
@@ -734,8 +732,7 @@ int sqlite3CodeRowTrigger(
int fire_this = 0;
/* determine whether we should code this trigger */
if( pTrigger->op == op && pTrigger->tr_tm == tr_tm &&
pTrigger->foreach == TK_ROW ){
if( pTrigger->op == op && pTrigger->tr_tm == tr_tm ){
fire_this = 1;
for(pStack=pParse->trigStack; pStack; pStack=pStack->pNext){
if( pStack->pTrigger==pTrigger ){