[sql] Import reference version of SQLite 3.17..

third_party/sqlite/sqlite-src-3170000/src/delete.c

+/*
+** 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
+** in order to generate code for DELETE FROM statements.
+*/
+#include "sqliteInt.h"
+
+/*
+** While a SrcList can in general represent multiple tables and subqueries
+** (as in the FROM clause of a SELECT statement) in this case it contains
+** the name of a single table, as one might find in an INSERT, DELETE,
+** or UPDATE statement.  Look up that table in the symbol table and
+** return a pointer.  Set an error message and return NULL if the table 
+** name is not found or if any other error occurs.
+**
+** The following fields are initialized appropriate in pSrc:
+**
+**    pSrc->a[0].pTab       Pointer to the Table object
+**    pSrc->a[0].pIndex     Pointer to the INDEXED BY index, if there is one
+**
+*/
+Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc){
+  struct SrcList_item *pItem = pSrc->a;
+  Table *pTab;
+  assert( pItem && pSrc->nSrc==1 );
+  pTab = sqlite3LocateTableItem(pParse, 0, pItem);
+  sqlite3DeleteTable(pParse->db, pItem->pTab);
+  pItem->pTab = pTab;
+  if( pTab ){
+    pTab->nTabRef++;
+  }
+  if( sqlite3IndexedByLookup(pParse, pItem) ){
+    pTab = 0;
+  }
+  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 sqlite3IsReadOnly(Parse *pParse, Table *pTab, int viewOk){
+  /* A table is not writable under the following circumstances:
+  **
+  **   1) It is a virtual table and no implementation of the xUpdate method
+  **      has been provided, or
+  **   2) It is a system table (i.e. sqlite_master), this call is not
+  **      part of a nested parse and writable_schema pragma has not 
+  **      been specified.
+  **
+  ** In either case leave an error message in pParse and return non-zero.
+  */
+  if( ( IsVirtual(pTab) 
+     && sqlite3GetVTable(pParse->db, pTab)->pMod->pModule->xUpdate==0 )
+   || ( (pTab->tabFlags & TF_Readonly)!=0
+     && (pParse->db->flags & SQLITE_WriteSchema)==0
+     && pParse->nested==0 )
+  ){
+    sqlite3ErrorMsg(pParse, "table %s may not be modified", pTab->zName);
+    return 1;
+  }
+
+#ifndef SQLITE_OMIT_VIEW
+  if( !viewOk && pTab->pSelect ){
+    sqlite3ErrorMsg(pParse,"cannot modify %s because it is a view",pTab->zName);
+    return 1;
+  }
+#endif
+  return 0;
+}
+
+
+#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
+/*
+** Evaluate a view and store its result in an ephemeral table.  The
+** pWhere argument is an optional WHERE clause that restricts the
+** set of rows in the view that are to be added to the ephemeral table.
+*/
+void sqlite3MaterializeView(
+  Parse *pParse,       /* Parsing context */
+  Table *pView,        /* View definition */
+  Expr *pWhere,        /* Optional WHERE clause to be added */
+  int iCur             /* Cursor number for ephemeral table */
+){
+  SelectDest dest;
+  Select *pSel;
+  SrcList *pFrom;
+  sqlite3 *db = pParse->db;
+  int iDb = sqlite3SchemaToIndex(db, pView->pSchema);
+  pWhere = sqlite3ExprDup(db, pWhere, 0);
+  pFrom = sqlite3SrcListAppend(db, 0, 0, 0);
+  if( pFrom ){
+    assert( pFrom->nSrc==1 );
+    pFrom->a[0].zName = sqlite3DbStrDup(db, pView->zName);
+    pFrom->a[0].zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName);
+    assert( pFrom->a[0].pOn==0 );
+    assert( pFrom->a[0].pUsing==0 );
+  }
+  pSel = sqlite3SelectNew(pParse, 0, pFrom, pWhere, 0, 0, 0, 
+                          SF_IncludeHidden, 0, 0);
+  sqlite3SelectDestInit(&dest, SRT_EphemTab, iCur);
+  sqlite3Select(pParse, pSel, &dest);
+  sqlite3SelectDelete(db, pSel);
+}
+#endif /* !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) */
+
+#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)
+/*
+** Generate an expression tree to implement the WHERE, ORDER BY,
+** and LIMIT/OFFSET portion of DELETE and UPDATE statements.
+**
+**     DELETE FROM table_wxyz WHERE a<5 ORDER BY a LIMIT 1;
+**                            \__________________________/
+**                               pLimitWhere (pInClause)
+*/
+Expr *sqlite3LimitWhere(
+  Parse *pParse,               /* The parser context */
+  SrcList *pSrc,               /* the FROM clause -- which tables to scan */
+  Expr *pWhere,                /* The WHERE clause.  May be null */
+  ExprList *pOrderBy,          /* The ORDER BY clause.  May be null */
+  Expr *pLimit,                /* The LIMIT clause.  May be null */
+  Expr *pOffset,               /* The OFFSET clause.  May be null */
+  char *zStmtType              /* Either DELETE or UPDATE.  For err msgs. */
+){
+  Expr *pWhereRowid = NULL;    /* WHERE rowid .. */
+  Expr *pInClause = NULL;      /* WHERE rowid IN ( select ) */
+  Expr *pSelectRowid = NULL;   /* SELECT rowid ... */
+  ExprList *pEList = NULL;     /* Expression list contaning only pSelectRowid */
+  SrcList *pSelectSrc = NULL;  /* SELECT rowid FROM x ... (dup of pSrc) */
+  Select *pSelect = NULL;      /* Complete SELECT tree */
+
+  /* Check that there isn't an ORDER BY without a LIMIT clause.
+  */
+  if( pOrderBy && (pLimit == 0) ) {
+    sqlite3ErrorMsg(pParse, "ORDER BY without LIMIT on %s", zStmtType);
+    goto limit_where_cleanup;
+  }
+
+  /* We only need to generate a select expression if there
+  ** is a limit/offset term to enforce.
+  */
+  if( pLimit == 0 ) {
+    /* if pLimit is null, pOffset will always be null as well. */
+    assert( pOffset == 0 );
+    return pWhere;
+  }
+
+  /* Generate a select expression tree to enforce the limit/offset 
+  ** term for the DELETE or UPDATE statement.  For example:
+  **   DELETE FROM table_a WHERE col1=1 ORDER BY col2 LIMIT 1 OFFSET 1
+  ** becomes:
+  **   DELETE FROM table_a WHERE rowid IN ( 
+  **     SELECT rowid FROM table_a WHERE col1=1 ORDER BY col2 LIMIT 1 OFFSET 1
+  **   );
+  */
+
+  pSelectRowid = sqlite3PExpr(pParse, TK_ROW, 0, 0);
+  if( pSelectRowid == 0 ) goto limit_where_cleanup;
+  pEList = sqlite3ExprListAppend(pParse, 0, pSelectRowid);
+  if( pEList == 0 ) goto limit_where_cleanup;
+
+  /* duplicate the FROM clause as it is needed by both the DELETE/UPDATE tree
+  ** and the SELECT subtree. */
+  pSelectSrc = sqlite3SrcListDup(pParse->db, pSrc, 0);
+  if( pSelectSrc == 0 ) {
+    sqlite3ExprListDelete(pParse->db, pEList);
+    goto limit_where_cleanup;
+  }
+
+  /* generate the SELECT expression tree. */
+  pSelect = sqlite3SelectNew(pParse,pEList,pSelectSrc,pWhere,0,0,
+                             pOrderBy,0,pLimit,pOffset);
+  if( pSelect == 0 ) return 0;
+
+  /* now generate the new WHERE rowid IN clause for the DELETE/UDPATE */
+  pWhereRowid = sqlite3PExpr(pParse, TK_ROW, 0, 0);
+  pInClause = pWhereRowid ? sqlite3PExpr(pParse, TK_IN, pWhereRowid, 0) : 0;
+  sqlite3PExprAddSelect(pParse, pInClause, pSelect);
+  return pInClause;
+
+limit_where_cleanup:
+  sqlite3ExprDelete(pParse->db, pWhere);
+  sqlite3ExprListDelete(pParse->db, pOrderBy);
+  sqlite3ExprDelete(pParse->db, pLimit);
+  sqlite3ExprDelete(pParse->db, pOffset);
+  return 0;
+}
+#endif /* defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) */
+       /*      && !defined(SQLITE_OMIT_SUBQUERY) */
+
+/*
+** 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);
+        sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iEphCur, iKey, iPk, nPk);
+      }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_RowData, 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 */
+      sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
+          iKey, nKey, count, OE_Default, eOnePass, aiCurOnePass[1]);
+    }
+  
+    /* 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);
+    }     
+  } /* 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;
+}
+/* Make sure "isView" and other macros defined above are undefined. Otherwise
+** they may interfere with compilation of other functions in this file
+** (or in another file, if this file becomes part of the amalgamation).  */
+#ifdef isView
+ #undef isView
+#endif
+#ifdef pTrigger
+ #undef pTrigger
+#endif
+
+/*
+** This routine generates VDBE code that causes a single row of a
+** single table to be deleted.  Both the original table entry and
+** all indices are removed.
+**
+** Preconditions:
+**
+**   1.  iDataCur is an open cursor on the btree that is the canonical data
+**       store for the table.  (This will be either the table itself,
+**       in the case of a rowid table, or the PRIMARY KEY index in the case
+**       of a WITHOUT ROWID table.)
+**
+**   2.  Read/write cursors for all indices of pTab must be open as
+**       cursor number iIdxCur+i for the i-th index.
+**
+**   3.  The primary key for the row to be deleted must be stored in a
+**       sequence of nPk memory cells starting at iPk.  If nPk==0 that means
+**       that a search record formed from OP_MakeRecord is contained in the
+**       single memory location iPk.
+**
+** eMode:
+**   Parameter eMode may be passed either ONEPASS_OFF (0), ONEPASS_SINGLE, or
+**   ONEPASS_MULTI.  If eMode is not ONEPASS_OFF, then the cursor
+**   iDataCur already points to the row to delete. If eMode is ONEPASS_OFF
+**   then this function must seek iDataCur to the entry identified by iPk
+**   and nPk before reading from it.
+**
+**   If eMode is ONEPASS_MULTI, then this call is being made as part
+**   of a ONEPASS delete that affects multiple rows. In this case, if 
+**   iIdxNoSeek is a valid cursor number (>=0) and is not the same as
+**   iDataCur, then its position should be preserved following the delete
+**   operation. Or, if iIdxNoSeek is not a valid cursor number, the
+**   position of iDataCur should be preserved instead.
+**
+** iIdxNoSeek:
+**   If iIdxNoSeek is a valid cursor number (>=0) not equal to iDataCur,
+**   then it identifies an index cursor (from within array of cursors
+**   starting at iIdxCur) that already points to the index entry to be deleted.
+**   Except, this optimization is disabled if there are BEFORE triggers since
+**   the trigger body might have moved the cursor.
+*/
+void sqlite3GenerateRowDelete(
+  Parse *pParse,     /* Parsing context */
+  Table *pTab,       /* Table containing the row to be deleted */
+  Trigger *pTrigger, /* List of triggers to (potentially) fire */
+  int iDataCur,      /* Cursor from which column data is extracted */
+  int iIdxCur,       /* First index cursor */
+  int iPk,           /* First memory cell containing the PRIMARY KEY */
+  i16 nPk,           /* Number of PRIMARY KEY memory cells */
+  u8 count,          /* If non-zero, increment the row change counter */
+  u8 onconf,         /* Default ON CONFLICT policy for triggers */
+  u8 eMode,          /* ONEPASS_OFF, _SINGLE, or _MULTI.  See above */
+  int iIdxNoSeek     /* Cursor number of cursor that does not need seeking */
+){
+  Vdbe *v = pParse->pVdbe;        /* Vdbe */
+  int iOld = 0;                   /* First register in OLD.* array */
+  int iLabel;                     /* Label resolved to end of generated code */
+  u8 opSeek;                      /* Seek opcode */
+
+  /* Vdbe is guaranteed to have been allocated by this stage. */
+  assert( v );
+  VdbeModuleComment((v, "BEGIN: GenRowDel(%d,%d,%d,%d)",
+                         iDataCur, iIdxCur, iPk, (int)nPk));
+
+  /* Seek cursor iCur to the row to delete. If this row no longer exists 
+  ** (this can happen if a trigger program has already deleted it), do
+  ** not attempt to delete it or fire any DELETE triggers.  */
+  iLabel = sqlite3VdbeMakeLabel(v);
+  opSeek = HasRowid(pTab) ? OP_NotExists : OP_NotFound;
+  if( eMode==ONEPASS_OFF ){
+    sqlite3VdbeAddOp4Int(v, opSeek, iDataCur, iLabel, iPk, nPk);
+    VdbeCoverageIf(v, opSeek==OP_NotExists);
+    VdbeCoverageIf(v, opSeek==OP_NotFound);
+  }
+ 
+  /* If there are any triggers to fire, allocate a range of registers to
+  ** use for the old.* references in the triggers.  */
+  if( sqlite3FkRequired(pParse, pTab, 0, 0) || pTrigger ){
+    u32 mask;                     /* Mask of OLD.* columns in use */
+    int iCol;                     /* Iterator used while populating OLD.* */
+    int addrStart;                /* Start of BEFORE trigger programs */
+
+    /* TODO: Could use temporary registers here. Also could attempt to
+    ** avoid copying the contents of the rowid register.  */
+    mask = sqlite3TriggerColmask(
+        pParse, pTrigger, 0, 0, TRIGGER_BEFORE|TRIGGER_AFTER, pTab, onconf
+    );
+    mask |= sqlite3FkOldmask(pParse, pTab);
+    iOld = pParse->nMem+1;
+    pParse->nMem += (1 + pTab->nCol);
+
+    /* Populate the OLD.* pseudo-table register array. These values will be 
+    ** used by any BEFORE and AFTER triggers that exist.  */
+    sqlite3VdbeAddOp2(v, OP_Copy, iPk, iOld);
+    for(iCol=0; iCol<pTab->nCol; iCol++){
+      testcase( mask!=0xffffffff && iCol==31 );
+      testcase( mask!=0xffffffff && iCol==32 );
+      if( mask==0xffffffff || (iCol<=31 && (mask & MASKBIT32(iCol))!=0) ){
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, iCol, iOld+iCol+1);
+      }
+    }
+
+    /* Invoke BEFORE DELETE trigger programs. */
+    addrStart = sqlite3VdbeCurrentAddr(v);
+    sqlite3CodeRowTrigger(pParse, pTrigger, 
+        TK_DELETE, 0, TRIGGER_BEFORE, pTab, iOld, onconf, iLabel
+    );
+
+    /* If any BEFORE triggers were coded, then seek the cursor to the 
+    ** row to be deleted again. It may be that the BEFORE triggers moved
+    ** the cursor or already deleted the row that the cursor was
+    ** pointing to.
+    **
+    ** Also disable the iIdxNoSeek optimization since the BEFORE trigger
+    ** may have moved that cursor.
+    */
+    if( addrStart<sqlite3VdbeCurrentAddr(v) ){
+      sqlite3VdbeAddOp4Int(v, opSeek, iDataCur, iLabel, iPk, nPk);
+      VdbeCoverageIf(v, opSeek==OP_NotExists);
+      VdbeCoverageIf(v, opSeek==OP_NotFound);
+      testcase( iIdxNoSeek>=0 );
+      iIdxNoSeek = -1;
+    }
+
+    /* Do FK processing. This call checks that any FK constraints that
+    ** refer to this table (i.e. constraints attached to other tables) 
+    ** are not violated by deleting this row.  */
+    sqlite3FkCheck(pParse, pTab, iOld, 0, 0, 0);
+  }
+
+  /* Delete the index and table entries. Skip this step if pTab is really
+  ** a view (in which case the only effect of the DELETE statement is to
+  ** fire the INSTEAD OF triggers).  
+  **
+  ** If variable 'count' is non-zero, then this OP_Delete instruction should
+  ** invoke the update-hook. The pre-update-hook, on the other hand should
+  ** be invoked unless table pTab is a system table. The difference is that
+  ** the update-hook is not invoked for rows removed by REPLACE, but the 
+  ** pre-update-hook is.
+  */ 
+  if( pTab->pSelect==0 ){
+    u8 p5 = 0;
+    sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur,0,iIdxNoSeek);
+    sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, (count?OPFLAG_NCHANGE:0));
+    if( pParse->nested==0 ){
+      sqlite3VdbeAppendP4(v, (char*)pTab, P4_TABLE);
+    }
+    if( eMode!=ONEPASS_OFF ){
+      sqlite3VdbeChangeP5(v, OPFLAG_AUXDELETE);
+    }
+    if( iIdxNoSeek>=0 && iIdxNoSeek!=iDataCur ){
+      sqlite3VdbeAddOp1(v, OP_Delete, iIdxNoSeek);
+    }
+    if( eMode==ONEPASS_MULTI ) p5 |= OPFLAG_SAVEPOSITION;
+    sqlite3VdbeChangeP5(v, p5);
+  }
+
+  /* Do any ON CASCADE, SET NULL or SET DEFAULT operations required to
+  ** handle rows (possibly in other tables) that refer via a foreign key
+  ** to the row just deleted. */ 
+  sqlite3FkActions(pParse, pTab, 0, iOld, 0, 0);
+
+  /* Invoke AFTER DELETE trigger programs. */
+  sqlite3CodeRowTrigger(pParse, pTrigger, 
+      TK_DELETE, 0, TRIGGER_AFTER, pTab, iOld, onconf, iLabel
+  );
+
+  /* Jump here if the row had already been deleted before any BEFORE
+  ** trigger programs were invoked. Or if a trigger program throws a 
+  ** RAISE(IGNORE) exception.  */
+  sqlite3VdbeResolveLabel(v, iLabel);
+  VdbeModuleComment((v, "END: GenRowDel()"));
+}
+
+/*
+** This routine generates VDBE code that causes the deletion of all
+** index entries associated with a single row of a single table, pTab
+**
+** Preconditions:
+**
+**   1.  A read/write cursor "iDataCur" must be open on the canonical storage
+**       btree for the table pTab.  (This will be either the table itself
+**       for rowid tables or to the primary key index for WITHOUT ROWID
+**       tables.)
+**
+**   2.  Read/write cursors for all indices of pTab must be open as
+**       cursor number iIdxCur+i for the i-th index.  (The pTab->pIndex
+**       index is the 0-th index.)
+**
+**   3.  The "iDataCur" cursor must be already be positioned on the row
+**       that is to be deleted.
+*/
+void sqlite3GenerateRowIndexDelete(
+  Parse *pParse,     /* Parsing and code generating context */
+  Table *pTab,       /* Table containing the row to be deleted */
+  int iDataCur,      /* Cursor of table holding data. */
+  int iIdxCur,       /* First index cursor */
+  int *aRegIdx,      /* Only delete if aRegIdx!=0 && aRegIdx[i]>0 */
+  int iIdxNoSeek     /* Do not delete from this cursor */
+){
+  int i;             /* Index loop counter */
+  int r1 = -1;       /* Register holding an index key */
+  int iPartIdxLabel; /* Jump destination for skipping partial index entries */
+  Index *pIdx;       /* Current index */
+  Index *pPrior = 0; /* Prior index */
+  Vdbe *v;           /* The prepared statement under construction */
+  Index *pPk;        /* PRIMARY KEY index, or NULL for rowid tables */
+
+  v = pParse->pVdbe;
+  pPk = HasRowid(pTab) ? 0 : sqlite3PrimaryKeyIndex(pTab);
+  for(i=0, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
+    assert( iIdxCur+i!=iDataCur || pPk==pIdx );
+    if( aRegIdx!=0 && aRegIdx[i]==0 ) continue;
+    if( pIdx==pPk ) continue;
+    if( iIdxCur+i==iIdxNoSeek ) continue;
+    VdbeModuleComment((v, "GenRowIdxDel for %s", pIdx->zName));
+    r1 = sqlite3GenerateIndexKey(pParse, pIdx, iDataCur, 0, 1,
+        &iPartIdxLabel, pPrior, r1);
+    sqlite3VdbeAddOp3(v, OP_IdxDelete, iIdxCur+i, r1,
+        pIdx->uniqNotNull ? pIdx->nKeyCol : pIdx->nColumn);
+    sqlite3ResolvePartIdxLabel(pParse, iPartIdxLabel);
+    pPrior = pIdx;
+  }
+}
+
+/*
+** Generate code that will assemble an index key and stores it in register
+** regOut.  The key with be for index pIdx which is an index on pTab.
+** iCur is the index of a cursor open on the pTab table and pointing to
+** the entry that needs indexing.  If pTab is a WITHOUT ROWID table, then
+** iCur must be the cursor of the PRIMARY KEY index.
+**
+** Return a register number which is the first in a block of
+** registers that holds the elements of the index key.  The
+** block of registers has already been deallocated by the time
+** this routine returns.
+**
+** If *piPartIdxLabel is not NULL, fill it in with a label and jump
+** to that label if pIdx is a partial index that should be skipped.
+** The label should be resolved using sqlite3ResolvePartIdxLabel().
+** A partial index should be skipped if its WHERE clause evaluates
+** to false or null.  If pIdx is not a partial index, *piPartIdxLabel
+** will be set to zero which is an empty label that is ignored by
+** sqlite3ResolvePartIdxLabel().
+**
+** The pPrior and regPrior parameters are used to implement a cache to
+** avoid unnecessary register loads.  If pPrior is not NULL, then it is
+** a pointer to a different index for which an index key has just been
+** computed into register regPrior.  If the current pIdx index is generating
+** its key into the same sequence of registers and if pPrior and pIdx share
+** a column in common, then the register corresponding to that column already
+** holds the correct value and the loading of that register is skipped.
+** This optimization is helpful when doing a DELETE or an INTEGRITY_CHECK 
+** on a table with multiple indices, and especially with the ROWID or
+** PRIMARY KEY columns of the index.
+*/
+int sqlite3GenerateIndexKey(
+  Parse *pParse,       /* Parsing context */
+  Index *pIdx,         /* The index for which to generate a key */
+  int iDataCur,        /* Cursor number from which to take column data */
+  int regOut,          /* Put the new key into this register if not 0 */
+  int prefixOnly,      /* Compute only a unique prefix of the key */
+  int *piPartIdxLabel, /* OUT: Jump to this label to skip partial index */
+  Index *pPrior,       /* Previously generated index key */
+  int regPrior         /* Register holding previous generated key */
+){
+  Vdbe *v = pParse->pVdbe;
+  int j;
+  int regBase;
+  int nCol;
+
+  if( piPartIdxLabel ){
+    if( pIdx->pPartIdxWhere ){
+      *piPartIdxLabel = sqlite3VdbeMakeLabel(v);
+      pParse->iSelfTab = iDataCur;
+      sqlite3ExprCachePush(pParse);
+      sqlite3ExprIfFalseDup(pParse, pIdx->pPartIdxWhere, *piPartIdxLabel, 
+                            SQLITE_JUMPIFNULL);
+    }else{
+      *piPartIdxLabel = 0;
+    }
+  }
+  nCol = (prefixOnly && pIdx->uniqNotNull) ? pIdx->nKeyCol : pIdx->nColumn;
+  regBase = sqlite3GetTempRange(pParse, nCol);
+  if( pPrior && (regBase!=regPrior || pPrior->pPartIdxWhere) ) pPrior = 0;
+  for(j=0; j<nCol; j++){
+    if( pPrior
+     && pPrior->aiColumn[j]==pIdx->aiColumn[j]
+     && pPrior->aiColumn[j]!=XN_EXPR
+    ){
+      /* This column was already computed by the previous index */
+      continue;
+    }
+    sqlite3ExprCodeLoadIndexColumn(pParse, pIdx, iDataCur, j, regBase+j);
+    /* If the column affinity is REAL but the number is an integer, then it
+    ** might be stored in the table as an integer (using a compact
+    ** representation) then converted to REAL by an OP_RealAffinity opcode.
+    ** But we are getting ready to store this value back into an index, where
+    ** it should be converted by to INTEGER again.  So omit the OP_RealAffinity
+    ** opcode if it is present */
+    sqlite3VdbeDeletePriorOpcode(v, OP_RealAffinity);
+  }
+  if( regOut ){
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol, regOut);
+    if( pIdx->pTable->pSelect ){
+      const char *zAff = sqlite3IndexAffinityStr(pParse->db, pIdx);
+      sqlite3VdbeChangeP4(v, -1, zAff, P4_TRANSIENT);
+    }
+  }
+  sqlite3ReleaseTempRange(pParse, regBase, nCol);
+  return regBase;
+}
+
+/*
+** If a prior call to sqlite3GenerateIndexKey() generated a jump-over label
+** because it was a partial index, then this routine should be called to
+** resolve that label.
+*/
+void sqlite3ResolvePartIdxLabel(Parse *pParse, int iLabel){
+  if( iLabel ){
+    sqlite3VdbeResolveLabel(pParse->pVdbe, iLabel);
+    sqlite3ExprCachePop(pParse);
+  }
+}