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added aggregate functions like count(*) (CVS 21)

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FossilOrigin-Name: dee7a8be88a95014534b90b96716d9e2e6b16579
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drh
2000-05-31 15:34:51 +00:00
parent dce2cbe65f
commit cce7d17614
15 changed files with 1395 additions and 995 deletions
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132
src/delete.c Normal file
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@@ -0,0 +1,132 @@
/*
** Copyright (c) 1999, 2000 D. Richard Hipp
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of the GNU General Public
** License as published by the Free Software Foundation; either
** version 2 of the License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
** General Public License for more details.
**
** You should have received a copy of the GNU General Public
** License along with this library; if not, write to the
** Free Software Foundation, Inc., 59 Temple Place - Suite 330,
** Boston, MA 02111-1307, USA.
**
** Author contact information:
** drh@hwaci.com
** http://www.hwaci.com/drh/
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle DELETE FROM statements.
**
** $Id: delete.c,v 1.1 2000/05/31 15:34:53 drh Exp $
*/
#include "sqliteInt.h"
/*
** Process a DELETE FROM statement.
*/
void sqliteDeleteFrom(
Parse *pParse, /* The parser context */
Token *pTableName, /* The table from which we should delete things */
Expr *pWhere /* The WHERE clause. May be null */
){
Vdbe *v; /* The virtual database engine */
Table *pTab; /* The table from which records will be deleted */
IdList *pTabList; /* An ID list holding pTab and nothing else */
int end, addr; /* A couple addresses of generated code */
int i; /* Loop counter */
WhereInfo *pWInfo; /* Information about the WHERE clause */
Index *pIdx; /* For looping over indices of the table */
/* Locate the table which we want to update. This table has to be
** put in an IdList structure because some of the subroutines will
** will be calling are designed to work with multiple tables and expect
** an IdList* parameter instead of just a Table* parameger.
*/
pTabList = sqliteIdListAppend(0, pTableName);
for(i=0; i<pTabList->nId; i++){
pTabList->a[i].pTab = sqliteFindTable(pParse->db, pTabList->a[i].zName);
if( pTabList->a[i].pTab==0 ){
sqliteSetString(&pParse->zErrMsg, "no such table: ",
pTabList->a[i].zName, 0);
pParse->nErr++;
goto delete_from_cleanup;
}
if( pTabList->a[i].pTab->readOnly ){
sqliteSetString(&pParse->zErrMsg, "table ", pTabList->a[i].zName,
" may not be modified", 0);
pParse->nErr++;
goto delete_from_cleanup;
}
}
pTab = pTabList->a[0].pTab;
/* Resolve the field names in all the expressions.
*/
if( pWhere ){
if( sqliteExprResolveIds(pParse, pTabList, pWhere) ){
goto delete_from_cleanup;
}
if( sqliteExprCheck(pParse, pWhere, 0, 0) ){
goto delete_from_cleanup;
}
}
/* Begin generating code.
*/
v = pParse->pVdbe;
if( v==0 ){
v = pParse->pVdbe = sqliteVdbeCreate(pParse->db->pBe);
}
if( v==0 ) goto delete_from_cleanup;
/* Begin the database scan
*/
sqliteVdbeAddOp(v, OP_ListOpen, 0, 0, 0, 0);
pWInfo = sqliteWhereBegin(pParse, pTabList, pWhere, 1);
if( pWInfo==0 ) goto delete_from_cleanup;
/* Remember the index of every item to be deleted.
*/
sqliteVdbeAddOp(v, OP_ListWrite, 0, 0, 0, 0);
/* End the database scan loop.
*/
sqliteWhereEnd(pWInfo);
/* Delete every item identified in the list.
*/
sqliteVdbeAddOp(v, OP_ListRewind, 0, 0, 0, 0);
for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
sqliteVdbeAddOp(v, OP_Open, i, 0, pIdx->zName, 0);
}
end = sqliteVdbeMakeLabel(v);
addr = sqliteVdbeAddOp(v, OP_ListRead, 0, end, 0, 0);
if( pTab->pIndex ){
sqliteVdbeAddOp(v, OP_Dup, 0, 0, 0, 0);
sqliteVdbeAddOp(v, OP_Fetch, 0, 0, 0, 0);
for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
int j;
sqliteVdbeAddOp(v, OP_Dup, 0, 0, 0, 0);
for(j=0; j<pIdx->nField; j++){
sqliteVdbeAddOp(v, OP_Field, 0, pIdx->aiField[j], 0, 0);
}
sqliteVdbeAddOp(v, OP_MakeKey, pIdx->nField, 0, 0, 0);
sqliteVdbeAddOp(v, OP_DeleteIdx, i, 0, 0, 0);
}
}
sqliteVdbeAddOp(v, OP_Delete, 0, 0, 0, 0);
sqliteVdbeAddOp(v, OP_Goto, 0, addr, 0, 0);
sqliteVdbeAddOp(v, OP_ListClose, 0, 0, 0, end);
delete_from_cleanup:
sqliteIdListDelete(pTabList);
sqliteExprDelete(pWhere);
return;
}