Exemple #1
0
/*
** Generate code for a DELETE FROM statement.
**
**     DELETE FROM table_wxyz WHERE a<5 AND b NOT NULL;
**                 \________/       \________________/
**                  pTabList              pWhere
*/
void sqlite3DeleteFrom(
  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 */
  int i;                 /* Loop counter */
  WhereInfo *pWInfo;     /* Information about the WHERE clause */
  Index *pIdx;           /* For looping over indices of the table */
  int iTabCur;           /* Cursor number for the table */
  int iDataCur = 0;      /* VDBE cursor for the canonical data source */
  int iIdxCur = 0;       /* Cursor number of the first index */
  int nIdx;              /* Number of indices */
  sqlite3 *db;           /* Main database structure */
  AuthContext sContext;  /* Authorization context */
  NameContext sNC;       /* Name context to resolve expressions in */
  int iDb;               /* Database number */
  int memCnt = -1;       /* Memory cell used for change counting */
  int rcauth;            /* Value returned by authorization callback */
  int eOnePass;          /* ONEPASS_OFF or _SINGLE or _MULTI */
  int aiCurOnePass[2];   /* The write cursors opened by WHERE_ONEPASS */
  u8 *aToOpen = 0;       /* Open cursor iTabCur+j if aToOpen[j] is true */
  Index *pPk;            /* The PRIMARY KEY index on the table */
  int iPk = 0;           /* First of nPk registers holding PRIMARY KEY value */
  i16 nPk = 1;           /* Number of columns in the PRIMARY KEY */
  int iKey;              /* Memory cell holding key of row to be deleted */
  i16 nKey;              /* Number of memory cells in the row key */
  int iEphCur = 0;       /* Ephemeral table holding all primary key values */
  int iRowSet = 0;       /* Register for rowset of rows to delete */
  int addrBypass = 0;    /* Address of jump over the delete logic */
  int addrLoop = 0;      /* Top of the delete loop */
  int addrEphOpen = 0;   /* Instruction to open the Ephemeral table */
  int bComplex;          /* True if there are triggers or FKs or
                         ** subqueries in the WHERE clause */
 
#ifndef SQLITE_OMIT_TRIGGER
  int isView;                  /* True if attempting to delete from a view */
  Trigger *pTrigger;           /* List of table triggers, if required */
#endif

  memset(&sContext, 0, sizeof(sContext));
  db = pParse->db;
  if( pParse->nErr || db->mallocFailed ){
    goto delete_from_cleanup;
  }
  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 = sqlite3SrcListLookup(pParse, pTabList);
  if( pTab==0 )  goto delete_from_cleanup;

  /* Figure out if we have any triggers and if the table being
  ** deleted from is a view
  */
#ifndef SQLITE_OMIT_TRIGGER
  pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
  isView = pTab->pSelect!=0;
  bComplex = pTrigger || sqlite3FkRequired(pParse, pTab, 0, 0);
#else
# define pTrigger 0
# define isView 0
#endif
#ifdef SQLITE_OMIT_VIEW
# undef isView
# define isView 0
#endif

  /* If pTab is really a view, make sure it has been initialized.
  */
  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
    goto delete_from_cleanup;
  }

  if( sqlite3IsReadOnly(pParse, pTab, (pTrigger?1:0)) ){
    goto delete_from_cleanup;
  }
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  assert( iDb<db->nDb );
  rcauth = sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0, 
                            db->aDb[iDb].zDbSName);
  assert( rcauth==SQLITE_OK || rcauth==SQLITE_DENY || rcauth==SQLITE_IGNORE );
  if( rcauth==SQLITE_DENY ){
    goto delete_from_cleanup;
  }
  assert(!isView || pTrigger);

  /* Assign cursor numbers to the table and all its indices.
  */
  assert( pTabList->nSrc==1 );
  iTabCur = pTabList->a[0].iCursor = pParse->nTab++;
  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){
    pParse->nTab++;
  }

  /* Start the view context
  */
  if( isView ){
    sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
  }

  /* Begin generating code.
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ){
    goto delete_from_cleanup;
  }
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, 1, iDb);

  /* If we are trying to delete from a view, realize that view into
  ** an ephemeral table.
  */
#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
  if( isView ){
    sqlite3MaterializeView(pParse, pTab, pWhere, iTabCur);
    iDataCur = iIdxCur = iTabCur;
  }
#endif

  /* Resolve the column names in the WHERE clause.
  */
  memset(&sNC, 0, sizeof(sNC));
  sNC.pParse = pParse;
  sNC.pSrcList = pTabList;
  if( sqlite3ResolveExprNames(&sNC, pWhere) ){
    goto delete_from_cleanup;
  }

  /* Initialize the counter of the number of rows deleted, if
  ** we are counting rows.
  */
  if( db->flags & SQLITE_CountRows ){
    memCnt = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Integer, 0, memCnt);
  }

#ifndef SQLITE_OMIT_TRUNCATE_OPTIMIZATION
  /* Special case: A DELETE without a WHERE clause deletes everything.
  ** It is easier just to erase the whole table. Prior to version 3.6.5,
  ** this optimization caused the row change count (the value returned by 
  ** API function sqlite3_count_changes) to be set incorrectly.  */
  if( rcauth==SQLITE_OK
   && pWhere==0
   && !bComplex
   && !IsVirtual(pTab)
#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
   && db->xPreUpdateCallback==0
#endif
  ){
    assert( !isView );
    sqlite3TableLock(pParse, iDb, pTab->tnum, 1, pTab->zName);
    if( HasRowid(pTab) ){
      sqlite3VdbeAddOp4(v, OP_Clear, pTab->tnum, iDb, memCnt,
                        pTab->zName, P4_STATIC);
    }
    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
      assert( pIdx->pSchema==pTab->pSchema );
      sqlite3VdbeAddOp2(v, OP_Clear, pIdx->tnum, iDb);
    }
  }else
#endif /* SQLITE_OMIT_TRUNCATE_OPTIMIZATION */
  {
    u16 wcf = WHERE_ONEPASS_DESIRED|WHERE_DUPLICATES_OK|WHERE_SEEK_TABLE;
    if( sNC.ncFlags & NC_VarSelect ) bComplex = 1;
    wcf |= (bComplex ? 0 : WHERE_ONEPASS_MULTIROW);
    if( HasRowid(pTab) ){
      /* For a rowid table, initialize the RowSet to an empty set */
      pPk = 0;
      nPk = 1;
      iRowSet = ++pParse->nMem;
      sqlite3VdbeAddOp2(v, OP_Null, 0, iRowSet);
    }else{
      /* For a WITHOUT ROWID table, create an ephemeral table used to
      ** hold all primary keys for rows to be deleted. */
      pPk = sqlite3PrimaryKeyIndex(pTab);
      assert( pPk!=0 );
      nPk = pPk->nKeyCol;
      iPk = pParse->nMem+1;
      pParse->nMem += nPk;
      iEphCur = pParse->nTab++;
      addrEphOpen = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEphCur, nPk);
      sqlite3VdbeSetP4KeyInfo(pParse, pPk);
    }
  
    /* Construct a query to find the rowid or primary key for every row
    ** to be deleted, based on the WHERE clause. Set variable eOnePass
    ** to indicate the strategy used to implement this delete:
    **
    **  ONEPASS_OFF:    Two-pass approach - use a FIFO for rowids/PK values.
    **  ONEPASS_SINGLE: One-pass approach - at most one row deleted.
    **  ONEPASS_MULTI:  One-pass approach - any number of rows may be deleted.
    */
    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0, wcf, iTabCur+1);
    if( pWInfo==0 ) goto delete_from_cleanup;
    eOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
    assert( IsVirtual(pTab)==0 || eOnePass!=ONEPASS_MULTI );
    assert( IsVirtual(pTab) || bComplex || eOnePass!=ONEPASS_OFF );
  
    /* Keep track of the number of rows to be deleted */
    if( db->flags & SQLITE_CountRows ){
      sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
    }
  
    /* Extract the rowid or primary key for the current row */
    if( pPk ){
      for(i=0; i<nPk; i++){
        assert( pPk->aiColumn[i]>=0 );
        sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur,
                                        pPk->aiColumn[i], iPk+i);
      }
      iKey = iPk;
    }else{
      iKey = pParse->nMem + 1;
      iKey = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iTabCur, iKey, 0);
      if( iKey>pParse->nMem ) pParse->nMem = iKey;
    }
  
    if( eOnePass!=ONEPASS_OFF ){
      /* For ONEPASS, no need to store the rowid/primary-key. There is only
      ** one, so just keep it in its register(s) and fall through to the
      ** delete code.  */
      nKey = nPk; /* OP_Found will use an unpacked key */
      aToOpen = sqlite3DbMallocRawNN(db, nIdx+2);
      if( aToOpen==0 ){
        sqlite3WhereEnd(pWInfo);
        goto delete_from_cleanup;
      }
      memset(aToOpen, 1, nIdx+1);
      aToOpen[nIdx+1] = 0;
      if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iTabCur] = 0;
      if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iTabCur] = 0;
      if( addrEphOpen ) sqlite3VdbeChangeToNoop(v, addrEphOpen);
    }else{
      if( pPk ){
        /* Add the PK key for this row to the temporary table */
        iKey = ++pParse->nMem;
        nKey = 0;   /* Zero tells OP_Found to use a composite key */
        sqlite3VdbeAddOp4(v, OP_MakeRecord, iPk, nPk, iKey,
            sqlite3IndexAffinityStr(pParse->db, pPk), nPk);
        sqlite3VdbeAddOp2(v, OP_IdxInsert, iEphCur, iKey);
      }else{
        /* Add the rowid of the row to be deleted to the RowSet */
        nKey = 1;  /* OP_Seek always uses a single rowid */
        sqlite3VdbeAddOp2(v, OP_RowSetAdd, iRowSet, iKey);
      }
    }
  
    /* If this DELETE cannot use the ONEPASS strategy, this is the 
    ** end of the WHERE loop */
    if( eOnePass!=ONEPASS_OFF ){
      addrBypass = sqlite3VdbeMakeLabel(v);
    }else{
      sqlite3WhereEnd(pWInfo);
    }
  
    /* Unless this is a view, open cursors for the table we are 
    ** deleting from and all its indices. If this is a view, then the
    ** only effect this statement has is to fire the INSTEAD OF 
    ** triggers.
    */
    if( !isView ){
      int iAddrOnce = 0;
      if( eOnePass==ONEPASS_MULTI ){
        iAddrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
      }
      testcase( IsVirtual(pTab) );
      sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, OPFLAG_FORDELETE,
                                 iTabCur, aToOpen, &iDataCur, &iIdxCur);
      assert( pPk || IsVirtual(pTab) || iDataCur==iTabCur );
      assert( pPk || IsVirtual(pTab) || iIdxCur==iDataCur+1 );
      if( eOnePass==ONEPASS_MULTI ) sqlite3VdbeJumpHere(v, iAddrOnce);
    }
  
    /* Set up a loop over the rowids/primary-keys that were found in the
    ** where-clause loop above.
    */
    if( eOnePass!=ONEPASS_OFF ){
      assert( nKey==nPk );  /* OP_Found will use an unpacked key */
      if( !IsVirtual(pTab) && aToOpen[iDataCur-iTabCur] ){
        assert( pPk!=0 || pTab->pSelect!=0 );
        sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, addrBypass, iKey, nKey);
        VdbeCoverage(v);
      }
    }else if( pPk ){
      addrLoop = sqlite3VdbeAddOp1(v, OP_Rewind, iEphCur); VdbeCoverage(v);
      sqlite3VdbeAddOp2(v, OP_RowKey, iEphCur, iKey);
      assert( nKey==0 );  /* OP_Found will use a composite key */
    }else{
      addrLoop = sqlite3VdbeAddOp3(v, OP_RowSetRead, iRowSet, 0, iKey);
      VdbeCoverage(v);
      assert( nKey==1 );
    }  
  
    /* Delete the row */
#ifndef SQLITE_OMIT_VIRTUALTABLE
    if( IsVirtual(pTab) ){
      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
      sqlite3VtabMakeWritable(pParse, pTab);
      sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iKey, pVTab, P4_VTAB);
      sqlite3VdbeChangeP5(v, OE_Abort);
      assert( eOnePass==ONEPASS_OFF || eOnePass==ONEPASS_SINGLE );
      sqlite3MayAbort(pParse);
      if( eOnePass==ONEPASS_SINGLE && sqlite3IsToplevel(pParse) ){
        pParse->isMultiWrite = 0;
      }
    }else
#endif
    {
      int count = (pParse->nested==0);    /* True to count changes */
      int iIdxNoSeek = -1;
      if( bComplex==0 && aiCurOnePass[1]!=iDataCur ){
        iIdxNoSeek = aiCurOnePass[1];
      }
      sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
          iKey, nKey, count, OE_Default, eOnePass, iIdxNoSeek);
    }
  
    /* End of the loop over all rowids/primary-keys. */
    if( eOnePass!=ONEPASS_OFF ){
      sqlite3VdbeResolveLabel(v, addrBypass);
      sqlite3WhereEnd(pWInfo);
    }else if( pPk ){
      sqlite3VdbeAddOp2(v, OP_Next, iEphCur, addrLoop+1); VdbeCoverage(v);
      sqlite3VdbeJumpHere(v, addrLoop);
    }else{
      sqlite3VdbeGoto(v, addrLoop);
      sqlite3VdbeJumpHere(v, addrLoop);
    }     
  
    /* Close the cursors open on the table and its indexes. */
    if( !isView && !IsVirtual(pTab) ){
      if( !pPk ) sqlite3VdbeAddOp1(v, OP_Close, iDataCur);
      for(i=0, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
        sqlite3VdbeAddOp1(v, OP_Close, iIdxCur + i);
      }
    }
  } /* End non-truncate path */

  /* Update the sqlite_sequence table by storing the content of the
  ** maximum rowid counter values recorded while inserting into
  ** autoincrement tables.
  */
  if( pParse->nested==0 && pParse->pTriggerTab==0 ){
    sqlite3AutoincrementEnd(pParse);
  }

  /* Return the number of rows that were deleted. If this routine is 
  ** generating code because of a call to sqlite3NestedParse(), do not
  ** invoke the callback function.
  */
  if( (db->flags&SQLITE_CountRows) && !pParse->nested && !pParse->pTriggerTab ){
    sqlite3VdbeAddOp2(v, OP_ResultRow, memCnt, 1);
    sqlite3VdbeSetNumCols(v, 1);
    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows deleted", SQLITE_STATIC);
  }

delete_from_cleanup:
  sqlite3AuthContextPop(&sContext);
  sqlite3SrcListDelete(db, pTabList);
  sqlite3ExprDelete(db, pWhere);
  sqlite3DbFree(db, aToOpen);
  return;
}
Exemple #2
0
/*
** Generate code for a DELETE FROM statement.
**
**     DELETE FROM table_wxyz WHERE a<5 AND b NOT NULL;
**                 \________/       \________________/
**                  pTabList              pWhere
*/
void sqlite3DeleteFrom(
  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 = 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 */
  int iCur;              /* VDBE Cursor number for pTab */
  sqlite3 *db;           /* Main database structure */
  AuthContext sContext;  /* Authorization context */
  NameContext sNC;       /* Name context to resolve expressions in */
  int iDb;               /* Database number */
  int memCnt = -1;       /* Memory cell used for change counting */
  int rcauth;            /* Value returned by authorization callback */

#ifndef SQLITE_OMIT_TRIGGER
  int isView;                  /* True if attempting to delete from a view */
  Trigger *pTrigger;           /* List of table triggers, if required */
#endif

  memset(&sContext, 0, sizeof(sContext));
  db = pParse->db;
  if( pParse->nErr || db->mallocFailed ){
    goto delete_from_cleanup;
  }
  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 = sqlite3SrcListLookup(pParse, pTabList);
  if( pTab==0 )  goto delete_from_cleanup;

  /* Figure out if we have any triggers and if the table being
  ** deleted from is a view
  */
#ifndef SQLITE_OMIT_TRIGGER
  pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
  isView = pTab->pSelect!=0;
#else
# define pTrigger 0
# define isView 0
#endif
#ifdef SQLITE_OMIT_VIEW
# undef isView
# define isView 0
#endif

  /* If pTab is really a view, make sure it has been initialized.
  */
  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
    goto delete_from_cleanup;
  }

  if( sqlite3IsReadOnly(pParse, pTab, (pTrigger?1:0)) ){
    goto delete_from_cleanup;
  }
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  assert( iDb<db->nDb );
  zDb = db->aDb[iDb].zName;
  rcauth = sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0, zDb);
  assert( rcauth==SQLITE_OK || rcauth==SQLITE_DENY || rcauth==SQLITE_IGNORE );
  if( rcauth==SQLITE_DENY ){
    goto delete_from_cleanup;
  }
  assert(!isView || pTrigger);

  /* Assign  cursor number to the table and all its indices.
  */
  assert( pTabList->nSrc==1 );
  iCur = pTabList->a[0].iCursor = pParse->nTab++;
  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    pParse->nTab++;
  }

  /* Start the view context
  */
  if( isView ){
    sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
  }

  /* Begin generating code.
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ){
    goto delete_from_cleanup;
  }
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, 1, iDb);

  /* If we are trying to delete from a view, realize that view into
  ** a ephemeral table.
  */
#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
  if( isView ){
    sqlite3MaterializeView(pParse, pTab, pWhere, iCur);
  }
#endif

  /* Resolve the column names in the WHERE clause.
  */
  memset(&sNC, 0, sizeof(sNC));
  sNC.pParse = pParse;
  sNC.pSrcList = pTabList;
  if( sqlite3ResolveExprNames(&sNC, pWhere) ){
    goto delete_from_cleanup;
  }

  /* Initialize the counter of the number of rows deleted, if
  ** we are counting rows.
  */
  if( db->flags & SQLITE_CountRows ){
    memCnt = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Integer, 0, memCnt);
  }

#ifndef SQLITE_OMIT_TRUNCATE_OPTIMIZATION
  /* Special case: A DELETE without a WHERE clause deletes everything.
  ** It is easier just to erase the whole table. Prior to version 3.6.5,
  ** this optimization caused the row change count (the value returned by 
  ** API function sqlite3_count_changes) to be set incorrectly.  */
  if( rcauth==SQLITE_OK && pWhere==0 && !pTrigger && !IsVirtual(pTab) 
   && 0==sqlite3FkRequired(pParse, pTab, 0, 0)
  ){
    assert( !isView );
    sqlite3VdbeAddOp4(v, OP_Clear, pTab->tnum, iDb, memCnt,
                      pTab->zName, P4_STATIC);
    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
      assert( pIdx->pSchema==pTab->pSchema );
      sqlite3VdbeAddOp2(v, OP_Clear, pIdx->tnum, iDb);
    }
  }else
#endif /* SQLITE_OMIT_TRUNCATE_OPTIMIZATION */
  /* The usual case: There is a WHERE clause so we have to scan through
  ** the table and pick which records to delete.
  */
  {
    int iRowSet = ++pParse->nMem;   /* Register for rowset of rows to delete */
    int iRowid = ++pParse->nMem;    /* Used for storing rowid values. */
    int regRowid;                   /* Actual register containing rowids */

    /* Collect rowids of every row to be deleted.
    */
    sqlite3VdbeAddOp2(v, OP_Null, 0, iRowSet);
    pWInfo = sqlite3WhereBegin(
        pParse, pTabList, pWhere, 0, 0, WHERE_DUPLICATES_OK, 0
    );
    if( pWInfo==0 ) goto delete_from_cleanup;
    regRowid = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iCur, iRowid, 0);
    sqlite3VdbeAddOp2(v, OP_RowSetAdd, iRowSet, regRowid);
    if( db->flags & SQLITE_CountRows ){
      sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
    }
    sqlite3WhereEnd(pWInfo);

    /* 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.  */
    end = sqlite3VdbeMakeLabel(v);

    /* Unless this is a view, open cursors for the table we are 
    ** deleting from and all its indices. If this is a view, then the
    ** only effect this statement has is to fire the INSTEAD OF 
    ** triggers.  */
    if( !isView ){
      sqlite3OpenTableAndIndices(pParse, pTab, iCur, OP_OpenWrite);
    }

    addr = sqlite3VdbeAddOp3(v, OP_RowSetRead, iRowSet, end, iRowid);

    /* Delete the row */
#ifndef SQLITE_OMIT_VIRTUALTABLE
    if( IsVirtual(pTab) ){
      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
      sqlite3VtabMakeWritable(pParse, pTab);
      sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iRowid, pVTab, P4_VTAB);
      sqlite3VdbeChangeP5(v, OE_Abort);
      sqlite3MayAbort(pParse);
    }else
#endif
    {
      int count = (pParse->nested==0);    /* True to count changes */
      sqlite3GenerateRowDelete(pParse, pTab, iCur, iRowid, count, pTrigger, OE_Default);
    }

    /* End of the delete loop */
    sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
    sqlite3VdbeResolveLabel(v, end);

    /* Close the cursors open on the table and its indexes. */
    if( !isView && !IsVirtual(pTab) ){
      for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
        sqlite3VdbeAddOp2(v, OP_Close, iCur + i, pIdx->tnum);
      }
      sqlite3VdbeAddOp1(v, OP_Close, iCur);
    }
  }

  /* Update the sqlite_sequence table by storing the content of the
  ** maximum rowid counter values recorded while inserting into
  ** autoincrement tables.
  */
  if( pParse->nested==0 && pParse->pTriggerTab==0 ){
    sqlite3AutoincrementEnd(pParse);
  }

  /* Return the number of rows that were deleted. If this routine is 
  ** generating code because of a call to sqlite3NestedParse(), do not
  ** invoke the callback function.
  */
  if( (db->flags&SQLITE_CountRows) && !pParse->nested && !pParse->pTriggerTab ){
    sqlite3VdbeAddOp2(v, OP_ResultRow, memCnt, 1);
    sqlite3VdbeSetNumCols(v, 1);
    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows deleted", SQLITE_STATIC);
  }

delete_from_cleanup:
  sqlite3AuthContextPop(&sContext);
  sqlite3SrcListDelete(db, pTabList);
  sqlite3ExprDelete(db, pWhere);
  return;
}