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Overview
| Comment: | Omit unnecessary CHECK constraints in UPDATE statements, when none of the columns referenced in the CHECK constraint are modified. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: | 02fbdbc782dd98f080bf4482d820f36c |
| User & Date: | drh 2016-02-10 16:52:24 |
Context
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2016-02-10
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| 18:24 | Fix to previous check-in: Make sure CHECK constraints involving the ROWID are not ignored when the ROWID changes. check-in: 7782cb1d user: drh tags: trunk | |
| 16:52 | Omit unnecessary CHECK constraints in UPDATE statements, when none of the columns referenced in the CHECK constraint are modified. check-in: 02fbdbc7 user: drh tags: trunk | |
| 16:03 | Omit NOT NULL checks on unchanging columns in an UPDATE. check-in: 6a3aaedf user: drh tags: trunk | |
Changes
Changes to src/insert.c.
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#endif #ifdef pTrigger #undef pTrigger #endif #ifdef tmask #undef tmask #endif /* ** Generate code to do constraint checks prior to an INSERT or an UPDATE ** on table pTab. ** ** The regNewData parameter is the first register in a range that contains ** the data to be inserted or the data after the update. There will be ................................................................................ #ifndef SQLITE_OMIT_CHECK if( pTab->pCheck && (db->flags & SQLITE_IgnoreChecks)==0 ){ ExprList *pCheck = pTab->pCheck; pParse->ckBase = regNewData+1; onError = overrideError!=OE_Default ? overrideError : OE_Abort; for(i=0; i<pCheck->nExpr; i++){ int allOk = sqlite3VdbeMakeLabel(v); sqlite3ExprIfTrue(pParse, pCheck->a[i].pExpr, allOk, SQLITE_JUMPIFNULL); if( onError==OE_Ignore ){ sqlite3VdbeGoto(v, ignoreDest); }else{ char *zName = pCheck->a[i].zName; if( zName==0 ) zName = pTab->zName; if( onError==OE_Replace ) onError = OE_Abort; /* IMP: R-15569-63625 */ sqlite3HaltConstraint(pParse, SQLITE_CONSTRAINT_CHECK, |
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#endif #ifdef pTrigger #undef pTrigger #endif #ifdef tmask #undef tmask #endif /* This is the Walker callback from checkConstraintUnchanged(). Set ** pWalker->eCode to 0 if this expression node references any of the ** columns that are being modifed by an UPDATE statement. */ static int checkConstraintExprNode(Walker *pWalker, Expr *pExpr){ if( pExpr->op==TK_COLUMN && pExpr->iColumn>=0 && pWalker->u.aiCol[pExpr->iColumn]>=0 ){ pWalker->eCode = 0; } return WRC_Continue; } /* ** pExpr is a CHECK constraint on a row that is being UPDATE-ed. The ** only columns that are modified by the UPDATE are those for which ** aiChng[i]>=0. Return true if CHECK constraint pExpr does not use ** any of the changing columns. In other words, return true if this ** CHECK constraint can be skipped when validating the new row in ** the UPDATE statement. */ static int checkConstraintUnchanged(Expr *pExpr, int *aiChng){ Walker w; memset(&w, 0, sizeof(w)); w.eCode = 1; w.xExprCallback = checkConstraintExprNode; w.u.aiCol = aiChng; sqlite3WalkExpr(&w, pExpr); return w.eCode; } /* ** Generate code to do constraint checks prior to an INSERT or an UPDATE ** on table pTab. ** ** The regNewData parameter is the first register in a range that contains ** the data to be inserted or the data after the update. There will be ................................................................................ #ifndef SQLITE_OMIT_CHECK if( pTab->pCheck && (db->flags & SQLITE_IgnoreChecks)==0 ){ ExprList *pCheck = pTab->pCheck; pParse->ckBase = regNewData+1; onError = overrideError!=OE_Default ? overrideError : OE_Abort; for(i=0; i<pCheck->nExpr; i++){ int allOk = sqlite3VdbeMakeLabel(v); Expr *pExpr = pCheck->a[i].pExpr; if( aiChng && checkConstraintUnchanged(pExpr, aiChng) ) continue; sqlite3ExprIfTrue(pParse, pExpr, allOk, SQLITE_JUMPIFNULL); if( onError==OE_Ignore ){ sqlite3VdbeGoto(v, ignoreDest); }else{ char *zName = pCheck->a[i].zName; if( zName==0 ) zName = pTab->zName; if( onError==OE_Replace ) onError = OE_Abort; /* IMP: R-15569-63625 */ sqlite3HaltConstraint(pParse, SQLITE_CONSTRAINT_CHECK, |
Changes to src/sqliteInt.h.
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union { /* Extra data for callback */
NameContext *pNC; /* Naming context */
int n; /* A counter */
int iCur; /* A cursor number */
SrcList *pSrcList; /* FROM clause */
struct SrcCount *pSrcCount; /* Counting column references */
struct CCurHint *pCCurHint; /* Used by codeCursorHint() */
} u;
};
/* Forward declarations */
int sqlite3WalkExpr(Walker*, Expr*);
int sqlite3WalkExprList(Walker*, ExprList*);
int sqlite3WalkSelect(Walker*, Select*);
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union { /* Extra data for callback */
NameContext *pNC; /* Naming context */
int n; /* A counter */
int iCur; /* A cursor number */
SrcList *pSrcList; /* FROM clause */
struct SrcCount *pSrcCount; /* Counting column references */
struct CCurHint *pCCurHint; /* Used by codeCursorHint() */
int *aiCol; /* array of column indexes */
} u;
};
/* Forward declarations */
int sqlite3WalkExpr(Walker*, Expr*);
int sqlite3WalkExprList(Walker*, ExprList*);
int sqlite3WalkSelect(Walker*, Select*);
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