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The case_sensitive_like pragma added.

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Test cases added for the LIKE optimization. (CVS 2592)

FossilOrigin-Name: 72ee21c05e618b6f46f5460f8c85779c72fe32d7
This commit is contained in:
drh
2005-08-14 01:20:37 +00:00
parent 3d94662a06
commit 55ef4d9758
11 changed files with 464 additions and 95 deletions
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41
src/where.c
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@@ -16,7 +16,7 @@
** so is applicable. Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.161 2005/08/13 16:13:05 drh Exp $
** $Id: where.c,v 1.162 2005/08/14 01:20:39 drh Exp $
*/
#include "sqliteInt.h"
@@ -467,54 +467,35 @@ static void exprAnalyzeAll(
** literal that does not begin with a wildcard.
*/
static int isLikeOrGlob(
sqlite3 *db, /* The database */
Expr *pExpr, /* Test this expression */
int *pnPattern, /* Number of non-wildcard prefix characters */
int *pisComplete /* True if the only wildcard is % in the last character */
){
const char *z;
Expr *pRight, *pLeft;
ExprList *pList;
int c, cnt;
char wc1, wc2, wc3;
if( pExpr->op!=TK_FUNCTION ){
char wc[3];
if( !sqlite3IsLikeFunction(db, pExpr, wc) ){
return 0;
}
if( pExpr->pList->nExpr!=2 ){
return 0;
}
if( pExpr->token.n!=4 ){
return 0;
}
z = pExpr->token.z;
if( sqlite3StrNICmp(z, "glob", 4)==0 ){
wc1 = '*';
wc2 = '?';
wc3 = '[';
}
#ifdef SQLITE_CASE_SENSITIVE_LIKE
else if( sqlite3StrNICmp(z, "like", 4)==0 ){
wc1 = '%';
wc2 = '_';
wc3 = '_';
}
#endif
else{
return 0;
}
pRight = pExpr->pList->a[0].pExpr;
pList = pExpr->pList;
pRight = pList->a[0].pExpr;
if( pRight->op!=TK_STRING ){
return 0;
}
pLeft = pExpr->pList->a[1].pExpr;
pLeft = pList->a[1].pExpr;
if( pLeft->op!=TK_COLUMN ){
return 0;
}
sqlite3DequoteExpr(pRight);
z = pRight->token.z;
for(cnt=0; (c=z[cnt])!=0 && c!=wc1 && c!=wc2 && c!=wc3; cnt++){}
for(cnt=0; (c=z[cnt])!=0 && c!=wc[0] && c!=wc[1] && c!=wc[2]; cnt++){}
if( cnt==0 || 255==(u8)z[cnt] ){
return 0;
}
*pisComplete = z[cnt]==wc1 && z[cnt+1]==0;
*pisComplete = z[cnt]==wc[0] && z[cnt+1]==0;
*pnPattern = cnt;
return 1;
}
@@ -671,7 +652,7 @@ or_not_possible:
/* Add constraints to reduce the search space on a LIKE or GLOB
** operator.
*/
if( isLikeOrGlob(pExpr, &nPattern, &isComplete) ){
if( isLikeOrGlob(pTerm->pWC->pParse->db, pExpr, &nPattern, &isComplete) ){
Expr *pLeft, *pRight;
Expr *pStr1, *pStr2;
Expr *pNewExpr1, *pNewExpr2;