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Overview
| Comment: | Do not run ON UPDATE actions of a foreign key constraint unless at least one column value really does change. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
71ac8e28e55ff0250ebe2fe239159ce2 |
| User & Date: | drh 2009-09-23 03:01:59.000 |
Context
|
2009-09-23
| ||
| 08:43 | Add missing comments to fkey.c. Also, change the terminology used for comments and names in fkey.c from "referenced/referencing" to "parent/child". This is arguably less correct, but is easier to follow. (check-in: 540c2d18e1 user: dan tags: trunk) | |
| 03:01 | Do not run ON UPDATE actions of a foreign key constraint unless at least one column value really does change. (check-in: 71ac8e28e5 user: drh tags: trunk) | |
| 02:29 | Generalize the IS and IS NOT operators so that their right-hand side can be an arbitrary expression and not simple the constant NULL. They work like = and <> except that NULL values compare equal to one another an unequal to everything else. (check-in: 98853f6104 user: drh tags: trunk) | |
Changes
Changes to src/fkey.c.
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}
static void fkTriggerDelete(sqlite3 *dbMem, Trigger *p){
if( p ){
TriggerStep *pStep = p->step_list;
sqlite3ExprDelete(dbMem, pStep->pWhere);
sqlite3ExprListDelete(dbMem, pStep->pExprList);
sqlite3DbFree(dbMem, p);
}
}
void sqlite3FkCheck(
Parse *pParse, /* Parse context */
Table *pTab, /* Row is being deleted from this table */
| > | 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 |
}
static void fkTriggerDelete(sqlite3 *dbMem, Trigger *p){
if( p ){
TriggerStep *pStep = p->step_list;
sqlite3ExprDelete(dbMem, pStep->pWhere);
sqlite3ExprListDelete(dbMem, pStep->pExprList);
sqlite3ExprDelete(dbMem, p->pWhen);
sqlite3DbFree(dbMem, p);
}
}
void sqlite3FkCheck(
Parse *pParse, /* Parse context */
Table *pTab, /* Row is being deleted from this table */
|
| ︙ | ︙ | |||
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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; /* First (only) step of trigger program */
Expr *pWhere = 0; /* WHERE clause of trigger step */
ExprList *pList = 0; /* Changes list if ON UPDATE CASCADE */
int i; /* Iterator variable */
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 */
| > | 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 |
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; /* First (only) step of trigger program */
Expr *pWhere = 0; /* WHERE clause of trigger step */
ExprList *pList = 0; /* Changes list if ON UPDATE CASCADE */
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 */
|
| ︙ | ︙ | |||
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sqlite3PExpr(pParse, TK_DOT,
sqlite3PExpr(pParse, TK_ID, 0, 0, &tOld),
sqlite3PExpr(pParse, TK_ID, 0, 0, &tToCol)
, 0)
, 0);
pWhere = sqlite3ExprAnd(db, pWhere, pEq);
if( 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);
| > > > > > > > > > > > > > > > > > > > | 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 |
sqlite3PExpr(pParse, TK_DOT,
sqlite3PExpr(pParse, TK_ID, 0, 0, &tOld),
sqlite3PExpr(pParse, TK_ID, 0, 0, &tToCol)
, 0)
, 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_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);
|
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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);
}
/* Re-enable the lookaside buffer, if it was disabled earlier. */
db->lookaside.bEnabled = enableLookaside;
| > > > > > | | | 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 |
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);
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);
if( db->mallocFailed==1 ){
fkTriggerDelete(db, pTrigger);
return 0;
}
pStep->op = (action!=OE_Cascade || pChanges) ? TK_UPDATE : TK_DELETE;
pStep->pTrig = pTrigger;
|
| ︙ | ︙ |