database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-11-06 15:49:35 +03:00
Code Activity

Perform deletes in a single pass. (CVS 2104)

Browse Source 
FossilOrigin-Name: a2e1c35b327e33684ab19e5f65727c42c7b2949c
This commit is contained in:
danielk1977
2004-11-16 15:50:19 +00:00
parent 6a43f9b3ff
commit ed326d7047
14 changed files with 205 additions and 229 deletions
Download Patch File Download Diff File Expand all files Collapse all files

109
src/delete.c
View File

@@ -12,7 +12,7 @@
** This file contains C code routines that are called by the parser
** to handle DELETE FROM statements.
**
** $Id: delete.c,v 1.88 2004/11/05 17:17:50 drh Exp $
** $Id: delete.c,v 1.89 2004/11/16 15:50:20 danielk1977 Exp $
*/
#include "sqliteInt.h"
@@ -64,7 +64,6 @@ void sqlite3OpenTableForReading(
sqlite3VdbeAddOp(v, OP_SetNumColumns, iCur, pTab->nCol);
}
/*
** Process a DELETE FROM statement.
*/
@@ -76,7 +75,7 @@ void sqlite3DeleteFrom(
Vdbe *v; /* The virtual database engine */
Table *pTab; /* The table from which records will be deleted */
const char *zDb; /* Name of database holding pTab */
int end, addr = 0; /* A couple addresses of generated code */
int addr = 0; /* 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 */
@@ -150,10 +149,15 @@ void sqlite3DeleteFrom(
oldIdx = pParse->nTab++;
}
/* Resolve the column names in all the expressions.
/* Resolve the column names in all the expressions. Allocate cursors
** for the table and indices first, in case an expression needs to use
** a cursor (e.g. an IN() expression).
*/
assert( pTabList->nSrc==1 );
iCur = pTabList->a[0].iCursor = pParse->nTab++;
for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
pParse->nTab++;
}
if( sqlite3ExprResolveAndCheck(pParse, pTabList, 0, pWhere, 0, 0) ){
goto delete_from_cleanup;
}
@@ -227,22 +231,6 @@ void sqlite3DeleteFrom(
}
}
/* Begin the database scan
*/
pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 1, 0);
if( pWInfo==0 ) goto delete_from_cleanup;
/* Remember the key of every item to be deleted.
*/
sqlite3VdbeAddOp(v, OP_ListWrite, 0, 0);
if( db->flags & SQLITE_CountRows ){
sqlite3VdbeAddOp(v, OP_AddImm, 1, 0);
}
/* End the database scan loop.
*/
sqlite3WhereEnd(pWInfo);
/* Open the pseudo-table used to store OLD if there are triggers.
*/
if( row_triggers_exist ){
@@ -250,80 +238,49 @@ void sqlite3DeleteFrom(
sqlite3VdbeAddOp(v, OP_SetNumColumns, oldIdx, pTab->nCol);
}
/* Delete every item whose key was written to the list during the
** database scan. We have to delete items after the scan is complete
** because deleting an item can change the scan order.
*/
sqlite3VdbeAddOp(v, OP_ListRewind, 0, 0);
end = sqlite3VdbeMakeLabel(v);
/* Open cursors for the table and indices we are deleting from. */
if( !isView ){
sqlite3OpenTableAndIndices(pParse, pTab, iCur, OP_OpenWrite);
}
/* This is the beginning of the delete loop when there are
** row triggers.
/* Begin the database scan
*/
pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0, isView?0:iCur);
if( pWInfo==0 ) goto delete_from_cleanup;
addr = pWInfo->iContinue;
/* If row-triggers exist, copy the record being deleted into the
** oldIdx psuedo-table. Then invoke the BEFORE triggers.
*/
if( row_triggers_exist ){
addr = sqlite3VdbeAddOp(v, OP_ListRead, 0, end);
sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
if( !isView ){
sqlite3OpenTableForReading(v, iCur, pTab);
}
sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
sqlite3VdbeAddOp(v, OP_Recno, iCur, 0);
sqlite3VdbeAddOp(v, OP_RowData, iCur, 0);
sqlite3VdbeAddOp(v, OP_PutIntKey, oldIdx, 0);
if( !isView ){
sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
}
(void)sqlite3CodeRowTrigger(pParse, TK_DELETE, 0, TK_BEFORE, pTab, -1,
oldIdx, (pParse->trigStack)?pParse->trigStack->orconf:OE_Default,
addr);
}
if( !isView ){
/* Open cursors for the table we are deleting from and all its
** indices. If there are row triggers, this happens inside the
** OP_ListRead loop because the cursor have to all be closed
** before the trigger fires. If there are no row triggers, the
** cursors are opened only once on the outside the loop.
*/
sqlite3OpenTableAndIndices(pParse, pTab, iCur, OP_OpenWrite);
/* This is the beginning of the delete loop when there are no
** row triggers */
if( !row_triggers_exist ){
addr = sqlite3VdbeAddOp(v, OP_ListRead, 0, end);
}
/* Delete the row */
sqlite3GenerateRowDelete(db, v, pTab, iCur, pParse->nested==0);
}
/* If there are row triggers, close all cursors then invoke
** the AFTER triggers
/* Delete the row. Increment the callback value if the count-rows flag
** is set.
*/
if( db->flags & SQLITE_CountRows ){
sqlite3VdbeAddOp(v, OP_AddImm, 1, 0);
}
sqlite3VdbeAddOp(v, OP_Recno, iCur, 0);
sqlite3GenerateRowDelete(db, v, pTab, iCur, pParse->nested==0);
/* Code the AFTER triggers. */
if( row_triggers_exist ){
if( !isView ){
for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
sqlite3VdbeAddOp(v, OP_Close, iCur + i, pIdx->tnum);
}
sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
}
(void)sqlite3CodeRowTrigger(pParse, TK_DELETE, 0, TK_AFTER, pTab, -1,
oldIdx, (pParse->trigStack)?pParse->trigStack->orconf:OE_Default,
addr);
}
/* End of the delete loop */
sqlite3VdbeAddOp(v, OP_Goto, 0, addr);
sqlite3VdbeResolveLabel(v, end);
sqlite3VdbeAddOp(v, OP_ListReset, 0, 0);
/* Close the cursors after the loop if there are no row triggers */
if( !row_triggers_exist ){
for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
sqlite3VdbeAddOp(v, OP_Close, iCur + i, pIdx->tnum);
}
sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
/* End the database scan loop and close indices. */
sqlite3WhereEnd(pWInfo);
for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
sqlite3VdbeAddOp(v, OP_Close, iCur + i, pIdx->tnum);
}
}