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Diffstat (limited to 'ext/sqlite/libsqlite/src/delete.c')
| -rw-r--r-- | ext/sqlite/libsqlite/src/delete.c | 393 |
1 files changed, 0 insertions, 393 deletions
diff --git a/ext/sqlite/libsqlite/src/delete.c b/ext/sqlite/libsqlite/src/delete.c deleted file mode 100644 index d83c314c79..0000000000 --- a/ext/sqlite/libsqlite/src/delete.c +++ /dev/null @@ -1,393 +0,0 @@ -/* -** 2001 September 15 -** -** The author disclaims copyright to this source code. In place of -** a legal notice, here is a blessing: -** -** May you do good and not evil. -** May you find forgiveness for yourself and forgive others. -** May you share freely, never taking more than you give. -** -************************************************************************* -** This file contains C code routines that are called by the parser -** to handle DELETE FROM statements. -** -** $Id$ -*/ -#include "sqliteInt.h" - -/* -** Look up every table that is named in pSrc. If any table is not found, -** add an error message to pParse->zErrMsg and return NULL. If all tables -** are found, return a pointer to the last table. -*/ -Table *sqliteSrcListLookup(Parse *pParse, SrcList *pSrc){ - Table *pTab = 0; - int i; - for(i=0; i<pSrc->nSrc; i++){ - const char *zTab = pSrc->a[i].zName; - const char *zDb = pSrc->a[i].zDatabase; - pTab = sqliteLocateTable(pParse, zTab, zDb); - pSrc->a[i].pTab = pTab; - } - return pTab; -} - -/* -** Check to make sure the given table is writable. If it is not -** writable, generate an error message and return 1. If it is -** writable return 0; -*/ -int sqliteIsReadOnly(Parse *pParse, Table *pTab, int viewOk){ - if( pTab->readOnly ){ - sqliteErrorMsg(pParse, "table %s may not be modified", pTab->zName); - return 1; - } - if( !viewOk && pTab->pSelect ){ - sqliteErrorMsg(pParse, "cannot modify %s because it is a view",pTab->zName); - return 1; - } - return 0; -} - -/* -** Process a DELETE FROM statement. -*/ -void sqliteDeleteFrom( - Parse *pParse, /* The parser context */ - SrcList *pTabList, /* 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 */ - const char *zDb; /* Name of database holding pTab */ - 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 */ - int iCur; /* VDBE Cursor number for pTab */ - sqlite *db; /* Main database structure */ - int isView; /* True if attempting to delete from a view */ - AuthContext sContext; /* Authorization context */ - - int row_triggers_exist = 0; /* True if any triggers exist */ - int before_triggers; /* True if there are BEFORE triggers */ - int after_triggers; /* True if there are AFTER triggers */ - int oldIdx = -1; /* Cursor for the OLD table of AFTER triggers */ - - sContext.pParse = 0; - if( pParse->nErr || sqlite_malloc_failed ){ - pTabList = 0; - goto delete_from_cleanup; - } - db = pParse->db; - assert( pTabList->nSrc==1 ); - - /* Locate the table which we want to delete. This table has to be - ** put in an SrcList structure because some of the subroutines we - ** will be calling are designed to work with multiple tables and expect - ** an SrcList* parameter instead of just a Table* parameter. - */ - pTab = sqliteSrcListLookup(pParse, pTabList); - if( pTab==0 ) goto delete_from_cleanup; - before_triggers = sqliteTriggersExist(pParse, pTab->pTrigger, - TK_DELETE, TK_BEFORE, TK_ROW, 0); - after_triggers = sqliteTriggersExist(pParse, pTab->pTrigger, - TK_DELETE, TK_AFTER, TK_ROW, 0); - row_triggers_exist = before_triggers || after_triggers; - isView = pTab->pSelect!=0; - if( sqliteIsReadOnly(pParse, pTab, before_triggers) ){ - goto delete_from_cleanup; - } - assert( pTab->iDb<db->nDb ); - zDb = db->aDb[pTab->iDb].zName; - if( sqliteAuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0, zDb) ){ - goto delete_from_cleanup; - } - - /* If pTab is really a view, make sure it has been initialized. - */ - if( isView && sqliteViewGetColumnNames(pParse, pTab) ){ - goto delete_from_cleanup; - } - - /* Allocate a cursor used to store the old.* data for a trigger. - */ - if( row_triggers_exist ){ - oldIdx = pParse->nTab++; - } - - /* Resolve the column names in all the expressions. - */ - assert( pTabList->nSrc==1 ); - iCur = pTabList->a[0].iCursor = pParse->nTab++; - if( pWhere ){ - if( sqliteExprResolveIds(pParse, pTabList, 0, pWhere) ){ - goto delete_from_cleanup; - } - if( sqliteExprCheck(pParse, pWhere, 0, 0) ){ - goto delete_from_cleanup; - } - } - - /* Start the view context - */ - if( isView ){ - sqliteAuthContextPush(pParse, &sContext, pTab->zName); - } - - /* Begin generating code. - */ - v = sqliteGetVdbe(pParse); - if( v==0 ){ - goto delete_from_cleanup; - } - sqliteBeginWriteOperation(pParse, row_triggers_exist, pTab->iDb); - - /* If we are trying to delete from a view, construct that view into - ** a temporary table. - */ - if( isView ){ - Select *pView = sqliteSelectDup(pTab->pSelect); - sqliteSelect(pParse, pView, SRT_TempTable, iCur, 0, 0, 0); - sqliteSelectDelete(pView); - } - - /* Initialize the counter of the number of rows deleted, if - ** we are counting rows. - */ - if( db->flags & SQLITE_CountRows ){ - sqliteVdbeAddOp(v, OP_Integer, 0, 0); - } - - /* Special case: A DELETE without a WHERE clause deletes everything. - ** It is easier just to erase the whole table. Note, however, that - ** this means that the row change count will be incorrect. - */ - if( pWhere==0 && !row_triggers_exist ){ - if( db->flags & SQLITE_CountRows ){ - /* If counting rows deleted, just count the total number of - ** entries in the table. */ - int endOfLoop = sqliteVdbeMakeLabel(v); - int addr; - if( !isView ){ - sqliteVdbeAddOp(v, OP_Integer, pTab->iDb, 0); - sqliteVdbeAddOp(v, OP_OpenRead, iCur, pTab->tnum); - } - sqliteVdbeAddOp(v, OP_Rewind, iCur, sqliteVdbeCurrentAddr(v)+2); - addr = sqliteVdbeAddOp(v, OP_AddImm, 1, 0); - sqliteVdbeAddOp(v, OP_Next, iCur, addr); - sqliteVdbeResolveLabel(v, endOfLoop); - sqliteVdbeAddOp(v, OP_Close, iCur, 0); - } - if( !isView ){ - sqliteVdbeAddOp(v, OP_Clear, pTab->tnum, pTab->iDb); - for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ - sqliteVdbeAddOp(v, OP_Clear, pIdx->tnum, pIdx->iDb); - } - } - } - - /* The usual case: There is a WHERE clause so we have to scan through - ** the table and pick which records to delete. - */ - else{ - /* Begin the database scan - */ - pWInfo = sqliteWhereBegin(pParse, pTabList, pWhere, 1, 0); - if( pWInfo==0 ) goto delete_from_cleanup; - - /* Remember the key of every item to be deleted. - */ - sqliteVdbeAddOp(v, OP_ListWrite, 0, 0); - if( db->flags & SQLITE_CountRows ){ - sqliteVdbeAddOp(v, OP_AddImm, 1, 0); - } - - /* End the database scan loop. - */ - sqliteWhereEnd(pWInfo); - - /* Open the pseudo-table used to store OLD if there are triggers. - */ - if( row_triggers_exist ){ - sqliteVdbeAddOp(v, OP_OpenPseudo, oldIdx, 0); - } - - /* 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. - */ - sqliteVdbeAddOp(v, OP_ListRewind, 0, 0); - end = sqliteVdbeMakeLabel(v); - - /* This is the beginning of the delete loop when there are - ** row triggers. - */ - if( row_triggers_exist ){ - addr = sqliteVdbeAddOp(v, OP_ListRead, 0, end); - sqliteVdbeAddOp(v, OP_Dup, 0, 0); - if( !isView ){ - sqliteVdbeAddOp(v, OP_Integer, pTab->iDb, 0); - sqliteVdbeAddOp(v, OP_OpenRead, iCur, pTab->tnum); - } - sqliteVdbeAddOp(v, OP_MoveTo, iCur, 0); - - sqliteVdbeAddOp(v, OP_Recno, iCur, 0); - sqliteVdbeAddOp(v, OP_RowData, iCur, 0); - sqliteVdbeAddOp(v, OP_PutIntKey, oldIdx, 0); - if( !isView ){ - sqliteVdbeAddOp(v, OP_Close, iCur, 0); - } - - sqliteCodeRowTrigger(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. - */ - pParse->nTab = iCur + 1; - sqliteOpenTableAndIndices(pParse, pTab, iCur); - - /* This is the beginning of the delete loop when there are no - ** row triggers */ - if( !row_triggers_exist ){ - addr = sqliteVdbeAddOp(v, OP_ListRead, 0, end); - } - - /* Delete the row */ - sqliteGenerateRowDelete(db, v, pTab, iCur, pParse->trigStack==0); - } - - /* If there are row triggers, close all cursors then invoke - ** the AFTER triggers - */ - if( row_triggers_exist ){ - if( !isView ){ - for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){ - sqliteVdbeAddOp(v, OP_Close, iCur + i, pIdx->tnum); - } - sqliteVdbeAddOp(v, OP_Close, iCur, 0); - } - sqliteCodeRowTrigger(pParse, TK_DELETE, 0, TK_AFTER, pTab, -1, - oldIdx, (pParse->trigStack)?pParse->trigStack->orconf:OE_Default, - addr); - } - - /* End of the delete loop */ - sqliteVdbeAddOp(v, OP_Goto, 0, addr); - sqliteVdbeResolveLabel(v, end); - sqliteVdbeAddOp(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){ - sqliteVdbeAddOp(v, OP_Close, iCur + i, pIdx->tnum); - } - sqliteVdbeAddOp(v, OP_Close, iCur, 0); - pParse->nTab = iCur; - } - } - sqliteVdbeAddOp(v, OP_SetCounts, 0, 0); - sqliteEndWriteOperation(pParse); - - /* - ** Return the number of rows that were deleted. - */ - if( db->flags & SQLITE_CountRows ){ - sqliteVdbeAddOp(v, OP_ColumnName, 0, 1); - sqliteVdbeChangeP3(v, -1, "rows deleted", P3_STATIC); - sqliteVdbeAddOp(v, OP_Callback, 1, 0); - } - -delete_from_cleanup: - sqliteAuthContextPop(&sContext); - sqliteSrcListDelete(pTabList); - sqliteExprDelete(pWhere); - return; -} - -/* -** This routine generates VDBE code that causes a single row of a -** single table to be deleted. -** -** The VDBE must be in a particular state when this routine is called. -** These are the requirements: -** -** 1. A read/write cursor pointing to pTab, the table containing the row -** to be deleted, must be opened as cursor number "base". -** -** 2. Read/write cursors for all indices of pTab must be open as -** cursor number base+i for the i-th index. -** -** 3. The record number of the row to be deleted must be on the top -** of the stack. -** -** This routine pops the top of the stack to remove the record number -** and then generates code to remove both the table record and all index -** entries that point to that record. -*/ -void sqliteGenerateRowDelete( - sqlite *db, /* The database containing the index */ - Vdbe *v, /* Generate code into this VDBE */ - Table *pTab, /* Table containing the row to be deleted */ - int iCur, /* Cursor number for the table */ - int count /* Increment the row change counter */ -){ - int addr; - addr = sqliteVdbeAddOp(v, OP_NotExists, iCur, 0); - sqliteGenerateRowIndexDelete(db, v, pTab, iCur, 0); - sqliteVdbeAddOp(v, OP_Delete, iCur, - (count?OPFLAG_NCHANGE:0) | OPFLAG_CSCHANGE); - sqliteVdbeChangeP2(v, addr, sqliteVdbeCurrentAddr(v)); -} - -/* -** This routine generates VDBE code that causes the deletion of all -** index entries associated with a single row of a single table. -** -** The VDBE must be in a particular state when this routine is called. -** These are the requirements: -** -** 1. A read/write cursor pointing to pTab, the table containing the row -** to be deleted, must be opened as cursor number "iCur". -** -** 2. Read/write cursors for all indices of pTab must be open as -** cursor number iCur+i for the i-th index. -** -** 3. The "iCur" cursor must be pointing to the row that is to be -** deleted. -*/ -void sqliteGenerateRowIndexDelete( - sqlite *db, /* The database containing the index */ - Vdbe *v, /* Generate code into this VDBE */ - Table *pTab, /* Table containing the row to be deleted */ - int iCur, /* Cursor number for the table */ - char *aIdxUsed /* Only delete if aIdxUsed!=0 && aIdxUsed[i]!=0 */ -){ - int i; - Index *pIdx; - - for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){ - int j; - if( aIdxUsed!=0 && aIdxUsed[i-1]==0 ) continue; - sqliteVdbeAddOp(v, OP_Recno, iCur, 0); - for(j=0; j<pIdx->nColumn; j++){ - int idx = pIdx->aiColumn[j]; - if( idx==pTab->iPKey ){ - sqliteVdbeAddOp(v, OP_Dup, j, 0); - }else{ - sqliteVdbeAddOp(v, OP_Column, iCur, idx); - } - } - sqliteVdbeAddOp(v, OP_MakeIdxKey, pIdx->nColumn, 0); - if( db->file_format>=4 ) sqliteAddIdxKeyType(v, pIdx); - sqliteVdbeAddOp(v, OP_IdxDelete, iCur+i, 0); - } -} |