SQLite

  ** expression being built up in zWhere.
  */
  if( pTab->pSchema!=pTempSchema ){
    sqlite3 *db = pParse->db;
    for(pTrig=sqlite3TriggerList(pParse, pTab); pTrig; pTrig=pTrig->pNext){
      if( pTrig->pSchema==pTempSchema ){
        if( !zWhere ){
          zWhere = sqlite3MPrintf(db, "name=%Q", pTrig->zName);
        }else{
          tmp = zWhere;
          zWhere = sqlite3MPrintf(db, "%s OR name=%Q", zWhere, pTrig->zName);
          sqlite3DbFree(db, tmp);
        }
      }
    }
  }
  return zWhere;
}

  assert( iDb>=0 );

#ifndef SQLITE_OMIT_TRIGGER
  /* Drop any table triggers from the internal schema. */
  for(pTrig=sqlite3TriggerList(pParse, pTab); pTrig; pTrig=pTrig->pNext){
    int iTrigDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
    assert( iTrigDb==iDb || iTrigDb==1 );
    sqlite3VdbeAddOp4(v, OP_DropTrigger, iTrigDb, 0, 0, pTrig->zName, 0);
  }
#endif

  /* Drop the table and index from the internal schema */
  sqlite3VdbeAddOp4(v, OP_DropTable, iDb, 0, 0, pTab->zName, 0);

  /* Reload the table, index and permanent trigger schemas. */

  const char *zName  /* Name of the table to be locked */
){
  int i;
  int nBytes;
  TableLock *p;

  assert( iDb>=0 );

  if( pParse->pRoot ){
    pParse = pParse->pRoot;
  }
  for(i=0; i<pParse->nTableLock; i++){
    p = &pParse->aTableLock[i];
    if( p->iDb==iDb && p->iTab==iTab ){
      p->isWriteLock = (p->isWriteLock || isWriteLock);
      return;
    }
  }

  nBytes = sizeof(TableLock) * (pParse->nTableLock+1);
  pParse->aTableLock =
      sqlite3DbReallocOrFree(pParse->db, pParse->aTableLock, nBytes);
  if( pParse->aTableLock ){
    p = &pParse->aTableLock[pParse->nTableLock++];
    p->iDb = iDb;
    p->iTab = iTab;
    p->isWriteLock = isWriteLock;
    p->zName = zName;

  if( v && ALWAYS(pParse->nErr==0) && !db->mallocFailed ){
#ifdef SQLITE_DEBUG
    FILE *trace = (db->flags & SQLITE_VdbeTrace)!=0 ? stdout : 0;
    sqlite3VdbeTrace(v, trace);
#endif
    assert( pParse->iCacheLevel==0 );  /* Disables and re-enables match */
    sqlite3VdbeMakeReady(v, pParse->nVar, pParse->nMem,
                         pParse->nTab, pParse->nArg, pParse->explain);
    pParse->rc = SQLITE_DONE;
    pParse->colNamesSet = 0;
  }else if( pParse->rc==SQLITE_OK ){
    pParse->rc = SQLITE_ERROR;
  }
  pParse->nTab = 0;
  pParse->nMem = 0;

** schema on any databases.  This can be used to position the OP_Goto
** early in the code, before we know if any database tables will be used.
*/
void sqlite3CodeVerifySchema(Parse *pParse, int iDb){
  sqlite3 *db;
  Vdbe *v;
  int mask;
  Parse *pRoot = pParse->pRoot;        /* Root parse structure */

  v = sqlite3GetVdbe(pParse);
  if( v==0 ) return;  /* This only happens if there was a prior error */
  db = pParse->db;
  if( pParse->cookieGoto==0 && pRoot==0 ){
    pParse->cookieGoto = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0)+1;
  }
  if( iDb>=0 ){
    if( pRoot==0 ){
      pRoot = pParse;
    }
    assert( iDb<db->nDb );
    assert( db->aDb[iDb].pBt!=0 || iDb==1 );
    assert( iDb<SQLITE_MAX_ATTACHED+2 );
    mask = 1<<iDb;
    if( (pRoot->cookieMask & mask)==0 ){
      pRoot->cookieMask |= mask;
      pRoot->cookieValue[iDb] = db->aDb[iDb].pSchema->schema_cookie;
      if( !OMIT_TEMPDB && iDb==1 ){
        sqlite3OpenTempDatabase(pRoot);
      }
    }
  }
}

/*
** Generate VDBE code that prepares for doing an operation that
** might change the database.
**
** This routine starts a new transaction if we are not already within
** a transaction.  If we are already within a transaction, then a checkpoint
** is set if the setStatement parameter is true.  A checkpoint should
** be set for operations that might fail (due to a constraint) part of
** the way through and which will need to undo some writes without having to
** rollback the whole transaction.  For operations where all constraints
** can be checked before any changes are made to the database, it is never
** necessary to undo a write and the checkpoint should not be set.
*/
void sqlite3BeginWriteOperation(Parse *pParse, int setStatement, int iDb){
  Parse *pRoot = pParse->pRoot;
  sqlite3CodeVerifySchema(pParse, iDb);
  if( pRoot==0 ){
    pRoot = pParse;
  }
  pRoot->writeMask |= 1<<iDb;
  if( setStatement && pParse->nested==0 && pParse->pRoot==0 ){
    /* Every place where this routine is called with setStatement!=0 has
    ** already successfully created a VDBE. */
    assert( pParse->pVdbe );
    sqlite3VdbeAddOp1(pParse->pVdbe, OP_Statement, iDb);
  }
}

  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 );

  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++;
  }

  v = sqlite3GetVdbe(pParse);
  if( v==0 ){
    goto delete_from_cleanup;
  }
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, (pTrigger?1:0), 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);
  }

    }
  }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 regOld = pParse->nMem + 1;  /* Start of array for old.* (if triggers) */
    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,WHERE_DUPLICATES_OK);
    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);

    /* If there are triggers, populate an array of registers with the
    ** data required by the old.* references in the trigger bodies.  */
    if( pTrigger ){
      u32 mask = 0;         /* Mask of OLD.* columns in use */
      u32 dummy = 0;        /* Unused. Initialized to prevent valgrind error. */
      pParse->nMem += pTab->nCol;

      /* Open the pseudo-table used to store OLD if there are triggers. */
      sqlite3TriggerUses(
          pParse, pTrigger, TK_DELETE, 0, pTab, OE_Default, &mask, &dummy);

      /* If the record is no longer present in the table, jump to the
      ** next iteration of the loop through the contents of the fifo.
      */
      sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, iRowid);

      /* Populate the OLD.* pseudo-table */
      assert( regOld==iRowid+1 );
      for(i=0; i<pTab->nCol; i++){
        if( mask==0xffffffff || mask&(1<<i) ){
          sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regOld+i);
        }

      }

      sqlite3CodeRowTrigger(pParse, pTrigger, 
          TK_DELETE, 0, TRIGGER_BEFORE, pTab, -1, regOld, OE_Default, addr
      );
    }

    if( !isView ){
      /* 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);
      }else
#endif
      {
        sqlite3GenerateRowDelete(pParse, pTab, iCur, iRowid, pParse->nested==0);
      }
    }


    /* Code the AFTER triggers. This is a no-op if there are no triggers. */

    sqlite3CodeRowTrigger(pParse, 

      pTrigger, TK_DELETE, 0, TRIGGER_AFTER, pTab, -1, regOld, OE_Default, addr
    );


    /* 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);

  **    *  The right-hand side is a correlated subquery
  **    *  The right-hand side is an expression list containing variables
  **    *  We are inside a trigger
  **
  ** If all of the above are false, then we can run this code just once
  ** save the results, and reuse the same result on subsequent invocations.
  */
  if( !ExprHasAnyProperty(pExpr, EP_VarSelect) && !pParse->pTriggerTab ){
    int mem = ++pParse->nMem;
    sqlite3VdbeAddOp1(v, OP_If, mem);
    testAddr = sqlite3VdbeAddOp2(v, OP_Integer, 1, mem);
    assert( testAddr>0 || pParse->db->mallocFailed );
  }

  switch( pExpr->op ){

      sqlite3ReleaseTempReg(pParse, r4);
      break;
    }
    case TK_UPLUS: {
      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
      break;
    }

    case TK_TRIGGER: {
      sqlite3VdbeAddOp3(v, OP_TriggerVal, pExpr->iColumn, target,pExpr->iTable);
      assert( pExpr->pTab );
      VdbeComment((v, "%s.%s", 
        (pExpr->iTable ? "new" : "old"), 
        (pExpr->iColumn<0 ? "rowid" : pExpr->pTab->aCol[pExpr->iColumn].zName)
      ));
      break;
    }


    /*
    ** Form A:
    **   CASE x WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
    **
    ** Form B:
    **   CASE WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END

      assert( db->mallocFailed || pParse->nErr>0 
           || pParse->iCacheLevel==iCacheLevel );
      sqlite3VdbeResolveLabel(v, endLabel);
      break;
    }
#ifndef SQLITE_OMIT_TRIGGER
    case TK_RAISE: {
      int vrc;
      if( !pParse->pTriggerTab ){
        sqlite3ErrorMsg(pParse,
                       "RAISE() may only be used within a trigger-program");
        return 0;
      }
      assert( pExpr->affinity==OE_Rollback 
           || pExpr->affinity==OE_Abort
           || pExpr->affinity==OE_Fail
           || pExpr->affinity==OE_Ignore
      );
      assert( !ExprHasProperty(pExpr, EP_IntValue) );



      vrc = (pExpr->affinity==OE_Ignore ? SQLITE_OK : SQLITE_CONSTRAINT);
      sqlite3VdbeAddOp4(v, OP_Halt, vrc, pExpr->affinity, 0, pExpr->u.zToken,0);



      break;
    }
#endif
  }
  sqlite3ReleaseTempReg(pParse, regFree1);
  sqlite3ReleaseTempReg(pParse, regFree2);
  return inReg;

  /* Allocate a VDBE
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto insert_cleanup;
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, pSelect || pTrigger, iDb);






#ifndef SQLITE_OMIT_XFER_OPT
  /* If the statement is of the form
  **
  **       INSERT INTO <table1> SELECT * FROM <table2>;
  **
  ** Then special optimizations can be applied that make the transfer
  ** very fast and which reduce fragmentation of indices.

  /* If there is no IDLIST term but the table has an integer primary
  ** key, the set the keyColumn variable to the primary key column index
  ** in the original table definition.
  */
  if( pColumn==0 && nColumn>0 ){
    keyColumn = pTab->iPKey;
  }






    
  /* Initialize the count of rows to be inserted
  */
  if( db->flags & SQLITE_CountRows ){
    regRowCount = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
  }

  /* Run the BEFORE and INSTEAD OF triggers, if there are any
  */
  endOfLoop = sqlite3VdbeMakeLabel(v);
  if( tmask & TRIGGER_BEFORE ){
    int regTrigRowid;
    int regCols;


    /* build the NEW.* reference row.  Note that if there is an INTEGER
    ** PRIMARY KEY into which a NULL is being inserted, that NULL will be
    ** translated into a unique ID for the row.  But on a BEFORE trigger,
    ** we do not know what the unique ID will be (because the insert has
    ** not happened yet) so we substitute a rowid of -1
    */

      sqlite3VdbeJumpHere(v, j1);
      sqlite3VdbeAddOp1(v, OP_MustBeInt, regTrigRowid);
    }

    /* Cannot have triggers on a virtual table. If it were possible,
    ** this block would have to account for hidden column.
    */
    assert( !IsVirtual(pTab) );

    /* Create the new column data
    */
    regCols = sqlite3GetTempRange(pParse, pTab->nCol);
    for(i=0; i<pTab->nCol; i++){
      if( pColumn==0 ){
        j = i;

      }else if( useTempTable ){
        sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, regCols+i); 
      }else{
        assert( pSelect==0 ); /* Otherwise useTempTable is true */
        sqlite3ExprCodeAndCache(pParse, pList->a[j].pExpr, regCols+i);
      }
    }



    /* If this is an INSERT on a view with an INSTEAD OF INSERT trigger,
    ** do not attempt any conversions before assembling the record.
    ** If this is a real table, attempt conversions as required by the
    ** table column affinities.
    */
    if( !isView ){
      sqlite3VdbeAddOp2(v, OP_Affinity, regCols, pTab->nCol);
      sqlite3TableAffinityStr(v, pTab);
    }





    /* Fire BEFORE or INSTEAD OF triggers */
    sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_BEFORE, 
        pTab, regCols, -1, onError, endOfLoop);


    sqlite3ReleaseTempReg(pParse, regTrigRowid);
    sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol);
  }

  /* Push the record number for the new entry onto the stack.  The
  ** record number is a randomly generate integer created by NewRowid
  ** except when the table has an INTEGER PRIMARY KEY column, in which
  ** case the record number is the same as that column. 
  */

  */
  if( (db->flags & SQLITE_CountRows)!=0 ){
    sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
  }

  if( pTrigger ){
    /* Code AFTER triggers */
    sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_AFTER, 
          pTab, regData, -1, onError, endOfLoop);


  }

  /* The bottom of the main insertion loop, if the data source
  ** is a SELECT statement.
  */
  sqlite3VdbeResolveLabel(v, endOfLoop);
  if( useTempTable ){

  }

insert_end:
  /* 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 inserted. 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, regRowCount, 1);
    sqlite3VdbeSetNumCols(v, 1);
    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows inserted", SQLITE_STATIC);
  }

insert_cleanup:
  sqlite3SrcListDelete(db, pTabList);

    }
  }
  regData = regRowid + 1;
  regRec = sqlite3GetTempReg(pParse);
  sqlite3VdbeAddOp3(v, OP_MakeRecord, regData, pTab->nCol, regRec);
  sqlite3TableAffinityStr(v, pTab);
  sqlite3ExprCacheAffinityChange(pParse, regData, pTab->nCol);





  if( pParse->nested ){
    pik_flags = 0;
  }else{
    pik_flags = OPFLAG_NCHANGE;
    pik_flags |= (isUpdate?OPFLAG_ISUPDATE:OPFLAG_LASTROWID);
  }
  if( appendBias ){

  if( zErrMsg ){
    sqlite3Error(db, rc, "%s", zErrMsg);
    sqlite3DbFree(db, zErrMsg);
  }else{
    sqlite3Error(db, rc, 0);
  }

  while( pParse->pCodedTrigger ){
    CodedTrigger *pT = pParse->pCodedTrigger;
    pParse->pCodedTrigger = pT->pNext;
    sqlite3VdbeProgramDelete(db, pT->pProgram, 0);
    sqlite3DbFree(db, pT);
  }

end_prepare:

  sqlite3StackFree(db, pParse);
  rc = sqlite3ApiExit(db, rc);
  assert( (rc&db->errMask)==rc );
  return rc;

  int cnt = 0;                      /* Number of matching column names */
  int cntTab = 0;                   /* Number of matching table names */
  sqlite3 *db = pParse->db;         /* The database connection */
  struct SrcList_item *pItem;       /* Use for looping over pSrcList items */
  struct SrcList_item *pMatch = 0;  /* The matching pSrcList item */
  NameContext *pTopNC = pNC;        /* First namecontext in the list */
  Schema *pSchema = 0;              /* Schema of the expression */
  int isTrigger = 0;                /* True if a new.* or old.* reference. */

  assert( pNC );     /* the name context cannot be NULL. */
  assert( zCol );    /* The Z in X.Y.Z cannot be NULL */
  assert( ~ExprHasAnyProperty(pExpr, EP_TokenOnly|EP_Reduced) );

  /* Initialize the node to no-match */
  pExpr->iTable = -1;

      }
    }

#ifndef SQLITE_OMIT_TRIGGER
    /* If we have not already resolved the name, then maybe 
    ** it is a new.* or old.* trigger argument reference
    */
    if( zDb==0 && zTab!=0 && cnt==0 && pParse->pTriggerTab!=0 ){

      Table *pTab = 0;
      u32 *piColMask = 0;
      if( pParse->triggerOp!=TK_DELETE && sqlite3StrICmp("new",zTab) == 0 ){
        pExpr->iTable = 1;

        pTab = pParse->pTriggerTab;
        piColMask = &(pParse->newmask);
      }else if( pParse->triggerOp!=TK_INSERT && sqlite3StrICmp("old",zTab)==0 ){
        pExpr->iTable = 0;

        pTab = pParse->pTriggerTab;
        piColMask = &(pParse->oldmask);
      }

      if( pTab ){ 
        int iCol;


        pSchema = pTab->pSchema;
        cntTab++;
        isTrigger = 1;
        for(iCol=0; iCol<pTab->nCol; iCol++){
          Column *pCol = &pTab->aCol[iCol];
          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
            cnt++;
            pExpr->iColumn = iCol==pTab->iPKey ? -1 : (i16)iCol;

            testcase( iCol==31 );
            testcase( iCol==32 );
            if( iCol>=32 ){
              *piColMask = 0xffffffff;
            }else{
              *piColMask |= ((u32)1)<<iCol;
            }

    ** the point where the name matched. */
    for(;;){
      assert( pTopNC!=0 );
      pTopNC->nRef++;
      if( pTopNC==pNC ) break;
      pTopNC = pTopNC->pNext;
    }
    if( isTrigger ){
      pExpr->pTab = pParse->pTriggerTab;
      pExpr->op = TK_TRIGGER;
    }
    return WRC_Prune;
  } else {
    return WRC_Abort;
  }
}

/*

  ** complete, since there may still exist Expr.pTab entries that
  ** refer to the subquery even after flattening.  Ticket #3346.
  **
  ** pSubitem->pTab is always non-NULL by test restrictions and tests above.
  */
  if( ALWAYS(pSubitem->pTab!=0) ){
    Table *pTabToDel = pSubitem->pTab;
    Parse *pRoot = (pParse->pRoot ? pParse->pRoot : pParse);
    if( pTabToDel->nRef==1 ){
      pTabToDel->pNextZombie = pRoot->pZombieTab;
      pRoot->pZombieTab = pTabToDel;
    }else{
      pTabToDel->nRef--;
    }
    pSubitem->pTab = 0;
  }

  /* The following loop runs once for each term in a compound-subquery

/*
** Size of the column cache
*/
#ifndef SQLITE_N_COLCACHE
# define SQLITE_N_COLCACHE 10
#endif

typedef struct CodedTrigger CodedTrigger;
struct CodedTrigger {
  SubProgram *pProgram;
  Trigger *pTrigger;
  u32 oldmask;            /* Mask of old.* columns accessed */
  u32 newmask;            /* Mask of new.* columns accessed */
  int orconf;             /* Default ON CONFLICT policy */
  CodedTrigger *pNext;
};

/*
** An SQL parser context.  A copy of this structure is passed through
** the parser and down into all the parser action routine in order to
** carry around information that is global to the entire parse.
**
** The structure is divided into two parts.  When the parser and code
** generate call themselves recursively, the first part of the structure

  int nTableLock;        /* Number of locks in aTableLock */
  TableLock *aTableLock; /* Required table locks for shared-cache mode */
#endif
  int regRowid;        /* Register holding rowid of CREATE TABLE entry */
  int regRoot;         /* Register holding root page number for new objects */
  AutoincInfo *pAinc;  /* Information about AUTOINCREMENT counters */

  /* Information used while coding trigger programs. */
  Parse *pRoot;        /* Root Parse structure */
  Table *pTriggerTab;  /* Table triggers are being coded for */
  u32 oldmask; 
  u32 newmask; 
  int triggerOp;       /* TK_UPDATE, TK_INSERT or TK_DELETE */
  int nArg;
  int orconf;          /* Default ON CONFLICT policy for trigger steps */

  /* Above is constant between recursions.  Below is reset before and after
  ** each recursion */

  int nVar;            /* Number of '?' variables seen in the SQL so far */
  int nVarExpr;        /* Number of used slots in apVarExpr[] */
  int nVarExprAlloc;   /* Number of allocated slots in apVarExpr[] */
  Expr **apVarExpr;    /* Pointers to :aaa and $aaaa wildcard expressions */
  int nAlias;          /* Number of aliased result set columns */
  int nAliasAlloc;     /* Number of allocated slots for aAlias[] */
  int *aAlias;         /* Register used to hold aliased result */
  u8 explain;          /* True if the EXPLAIN flag is found on the query */
  Token sNameToken;    /* Token with unqualified schema object name */
  Token sLastToken;    /* The last token parsed */
  const char *zTail;   /* All SQL text past the last semicolon parsed */
  Table *pNewTable;    /* A table being constructed by CREATE TABLE */
  Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */
#if 0
  TriggerStack *trigStack;  /* Trigger actions being coded */
#endif
  const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */
#ifndef SQLITE_OMIT_VIRTUALTABLE
  Token sArg;                /* Complete text of a module argument */
  u8 declareVtab;            /* True if inside sqlite3_declare_vtab() */
  int nVtabLock;             /* Number of virtual tables to lock */
  Table **apVtabLock;        /* Pointer to virtual tables needing locking */
#endif
  int nHeight;            /* Expression tree height of current sub-select */
  Table *pZombieTab;      /* List of Table objects to delete after code gen */
  CodedTrigger *pCodedTrigger;    /* Linked list of coded triggers */
};

#ifdef SQLITE_OMIT_VIRTUALTABLE
  #define IN_DECLARE_VTAB 0
#else
  #define IN_DECLARE_VTAB (pParse->declareVtab)
#endif

 *    linked list is stored as the "pTrigger" member of the associated
 *    struct Table.
 *
 * The "step_list" member points to the first element of a linked list
 * containing the SQL statements specified as the trigger program.
 */
struct Trigger {
  char *zName;            /* The name of the trigger                        */
  char *table;            /* The table or view to which the trigger applies */
  u8 op;                  /* One of TK_DELETE, TK_UPDATE, TK_INSERT         */
  u8 tr_tm;               /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
  Expr *pWhen;            /* The WHEN clause of the expression (may be NULL) */
  IdList *pColumns;       /* If this is an UPDATE OF <column-list> trigger,
                             the <column-list> is stored here */
  Schema *pSchema;        /* Schema containing the trigger */

  void sqlite3BeginTrigger(Parse*, Token*,Token*,int,int,IdList*,SrcList*,
                           Expr*,int, int);
  void sqlite3FinishTrigger(Parse*, TriggerStep*, Token*);
  void sqlite3DropTrigger(Parse*, SrcList*, int);
  void sqlite3DropTriggerPtr(Parse*, Trigger*);
  Trigger *sqlite3TriggersExist(Parse *, Table*, int, ExprList*, int *pMask);
  Trigger *sqlite3TriggerList(Parse *, Table *);
  void sqlite3CodeRowTrigger(Parse*, Trigger *, int, ExprList*, int, Table *,
                            int, int, int, int);
  void sqliteViewTriggers(Parse*, Table*, Expr*, int, ExprList*);
  void sqlite3DeleteTriggerStep(sqlite3*, TriggerStep*);
  TriggerStep *sqlite3TriggerSelectStep(sqlite3*,Select*);
  TriggerStep *sqlite3TriggerInsertStep(sqlite3*,Token*, IdList*,
                                        ExprList*,Select*,u8);
  TriggerStep *sqlite3TriggerUpdateStep(sqlite3*,Token*,ExprList*, Expr*, u8);
  TriggerStep *sqlite3TriggerDeleteStep(sqlite3*,Token*, Expr*);
  void sqlite3DeleteTrigger(sqlite3*, Trigger*);
  void sqlite3UnlinkAndDeleteTrigger(sqlite3*,int,const char*);
  void sqlite3TriggerUses(Parse*,Trigger*,int,ExprList*,Table*,int,u32*,u32*);
#else
# define sqlite3TriggersExist(B,C,D,E,F) 0
# define sqlite3DeleteTrigger(A,B)
# define sqlite3DropTriggerPtr(A,B)
# define sqlite3UnlinkAndDeleteTrigger(A,B,C)
# define sqlite3CodeRowTrigger(A,B,C,D,E,F,G,H,I,J)
# define sqlite3TriggerList(X, Y) 0
#endif

int sqlite3JoinType(Parse*, Token*, Token*, Token*);
void sqlite3CreateForeignKey(Parse*, ExprList*, Token*, ExprList*, int);
void sqlite3DeferForeignKey(Parse*, int);
#ifndef SQLITE_OMIT_AUTHORIZATION

  if (tr_tm == TK_INSTEAD){
    tr_tm = TK_BEFORE;
  }

  /* Build the Trigger object */
  pTrigger = (Trigger*)sqlite3DbMallocZero(db, sizeof(Trigger));
  if( pTrigger==0 ) goto trigger_cleanup;
  pTrigger->zName = zName;
  zName = 0;
  pTrigger->table = sqlite3DbStrDup(db, pTableName->a[0].zName);
  pTrigger->pSchema = db->aDb[iDb].pSchema;
  pTrigger->pTabSchema = pTab->pSchema;
  pTrigger->op = (u8)op;
  pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER;
  pTrigger->pWhen = sqlite3ExprDup(db, pWhen, EXPRDUP_REDUCE);

  DbFixer sFix;
  int iDb;                                 /* Database containing the trigger */
  Token nameToken;           /* Trigger name for error reporting */

  pTrig = pParse->pNewTrigger;
  pParse->pNewTrigger = 0;
  if( NEVER(pParse->nErr) || !pTrig ) goto triggerfinish_cleanup;
  zName = pTrig->zName;
  iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
  pTrig->step_list = pStepList;
  while( pStepList ){
    pStepList->pTrig = pTrig;
    pStepList = pStepList->pNext;
  }
  nameToken.z = pTrig->zName;
  nameToken.n = sqlite3Strlen30(nameToken.z);
  if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", &nameToken) 
          && sqlite3FixTriggerStep(&sFix, pTrig->step_list) ){
    goto triggerfinish_cleanup;
  }

  /* if we are not initializing, and this trigger is not on a TEMP table, 

/* 
** Recursively delete a Trigger structure
*/
void sqlite3DeleteTrigger(sqlite3 *db, Trigger *pTrigger){
  if( pTrigger==0 ) return;
  sqlite3DeleteTriggerStep(db, pTrigger->step_list);
  sqlite3DbFree(db, pTrigger->zName);
  sqlite3DbFree(db, pTrigger->table);
  sqlite3ExprDelete(db, pTrigger->pWhen);
  sqlite3IdListDelete(db, pTrigger->pColumns);
  sqlite3DbFree(db, pTrigger);
}

/*

      { OP_Delete,     0, 0,        0},
      { OP_Next,       0, ADDR(1),  0}, /* 8 */
    };

    sqlite3BeginWriteOperation(pParse, 0, iDb);
    sqlite3OpenMasterTable(pParse, iDb);
    base = sqlite3VdbeAddOpList(v,  ArraySize(dropTrigger), dropTrigger);
    sqlite3VdbeChangeP4(v, base+1, pTrigger->zName, 0);
    sqlite3VdbeChangeP4(v, base+4, "trigger", P4_STATIC);
    sqlite3ChangeCookie(pParse, iDb);
    sqlite3VdbeAddOp2(v, OP_Close, 0, 0);
    sqlite3VdbeAddOp4(v, OP_DropTrigger, iDb, 0, 0, pTrigger->zName, 0);
    if( pParse->nMem<3 ){
      pParse->nMem = 3;
    }
  }
}

/*

** trigger.  
*/
static int codeTriggerProgram(
  Parse *pParse,            /* The parser context */
  TriggerStep *pStepList,   /* List of statements inside the trigger body */
  int orconfin              /* Conflict algorithm. (OE_Abort, etc) */  
){
  TriggerStep * pStep = pStepList;

  Vdbe *v = pParse->pVdbe;
  sqlite3 *db = pParse->db;

  assert( pParse->pRoot );
  assert( pStep!=0 );
  assert( v!=0 );
/* sqlite3VdbeAddOp2(v, OP_ContextPush, 0, 0); */

  while( pStep ){
    /* Figure out the ON CONFLICT policy that will be used for this step
    ** of the trigger program. If the statement that caused this trigger
    ** to fire had an explicit ON CONFLICT, then use it. Otherwise, use
    ** the ON CONFLICT policy that was specified as part of the trigger
    ** step statement. Example:
    **
    **   CREATE TRIGGER AFTER INSERT ON t1 BEGIN;
    **     INSERT OR REPLACE INTO t2 VALUES(new.a, new.b);
    **   END;
    **
    **   INSERT INTO t1 ... ;            -- insert into t2 uses REPLACE policy
    **   INSERT OR IGNORE INTO t1 ... ;  -- insert into t2 uses IGNORE policy
    */
    pParse->orconf = (orconfin==OE_Default)?pStep->orconf:orconfin;

    switch( pStep->op ){
      case TK_UPDATE: {



        sqlite3Update(pParse, 
          targetSrcList(pParse, pStep),
          sqlite3ExprListDup(db, pStep->pExprList, 0), 
          sqlite3ExprDup(db, pStep->pWhere, 0), 

          pParse->orconf
        );
        break;
      }
      case TK_INSERT: {



        sqlite3Insert(pParse, 
          targetSrcList(pParse, pStep),
          sqlite3ExprListDup(db, pStep->pExprList, 0), 
          sqlite3SelectDup(db, pStep->pSelect, 0), 
          sqlite3IdListDup(db, pStep->pIdList), 

          pParse->orconf
        );
        break;
      }
      case TK_DELETE: {



        sqlite3DeleteFrom(pParse, 
          targetSrcList(pParse, pStep),
          sqlite3ExprDup(db, pStep->pWhere, 0)

        );
        break;
      }
      default: assert( pStep->op==TK_SELECT ); {
        SelectDest sDest;
        Select *pSelect = sqlite3SelectDup(db, pStep->pSelect, 0);
        sqlite3SelectDestInit(&sDest, SRT_Discard, 0);
        sqlite3Select(pParse, pSelect, &sDest);
        sqlite3SelectDelete(db, pSelect);
        break;
      }
    } 
    pStep = pStep->pNext;
  }
/* sqlite3VdbeAddOp2(v, OP_ContextPop, 0, 0); */

  return 0;
}

#ifdef SQLITE_DEBUG
/*
** This function is used to add VdbeComment() annotations to a VDBE
** program. It is not used in production code, only for debugging.
*/
static const char *onErrorText(int onError){
  switch( onError ){
    case OE_Abort:    return "abort";
    case OE_Rollback: return "rollback";
    case OE_Fail:     return "fail";
    case OE_Replace:  return "replace";
    case OE_Ignore:   return "ignore";
    case OE_Default:  return "default";
  }
  return "n/a";
}
#endif

/*
** Parse context structure pFrom has just been used to create a sub-vdbe
** (trigger program). If an error has occurred, transfer error information
** from pFrom to pTo.
*/
static void transferParseError(Parse *pTo, Parse *pFrom){
  assert( pFrom->zErrMsg==0 || pFrom->nErr );
  assert( pTo->zErrMsg==0 || pTo->nErr );
  if( pTo->nErr==0 ){
    pTo->zErrMsg = pFrom->zErrMsg;
    pTo->nErr = pFrom->nErr;
  }else{
    sqlite3DbFree(pFrom->db, pFrom->zErrMsg);
  }
}

static CodedTrigger *codeRowTrigger(
  Parse *pRoot,        /* Root parse context */
  Parse *pParse,       /* Current parse context */
  Trigger *pTrigger,   /* Trigger to code */
  int op,              /* One of TK_UPDATE, TK_INSERT, TK_DELETE */
  Table *pTab,         /* The table to code triggers from */
  int orconf
){
  sqlite3 *db = pParse->db;
  CodedTrigger *pC;
  Expr *pWhen = 0;            /* Duplicate of trigger WHEN expression */
  Vdbe *v;                    /* Temporary VM */
  AuthContext sContext;       /* Auth context for sub-vdbe */
  NameContext sNC;            /* Name context for sub-vdbe */
  SubProgram *pProgram = 0;   /* Sub-vdbe for trigger program */
  Parse *pSubParse;           /* Parse context for sub-vdbe */
  int iEndTrigger = 0;        /* Label to jump to if WHEN is false */

  pC = sqlite3DbMallocZero(db, sizeof(CodedTrigger));
  if( !pC ) return 0;
  pC->pNext = pRoot->pCodedTrigger;
  pRoot->pCodedTrigger = pC;
  pC->pProgram = pProgram = sqlite3DbMallocZero(db, sizeof(SubProgram));
  if( !pProgram ) return 0;
  pProgram->nRef = 1;
  pSubParse = sqlite3StackAllocZero(db, sizeof(Parse));
  if( !pSubParse ) return 0;

  pC->pProgram = pProgram;
  pC->pTrigger = pTrigger;
  pC->orconf = orconf;

  memset(&sNC, 0, sizeof(sNC));
  sNC.pParse = pSubParse;
  pSubParse->db = db;
  pSubParse->pTriggerTab = pTab;
  pSubParse->pRoot = pRoot;

  /* Push an entry on to the auth context stack */
  sqlite3AuthContextPush(pParse, &sContext, pTrigger->name);

  v = sqlite3GetVdbe(pSubParse);
  if( v ){
    VdbeComment((v, "Trigger: %s (%s %s%s%s ON %s) (%s)", pTrigger->zName,
      (pTrigger->tr_tm==TRIGGER_BEFORE ? "BEFORE" : "AFTER"),
        (op==TK_UPDATE ? "UPDATE" : ""),
        (op==TK_INSERT ? "INSERT" : ""),
        (op==TK_DELETE ? "DELETE" : ""),
      pTab->zName, onErrorText(orconf)
    ));

    if( pTrigger->pWhen ){
      /* Code the WHEN clause. If it evaluates to false (or NULL) the 
      ** sub-vdbe is immediately halted.  */
      pWhen = sqlite3ExprDup(db, pTrigger->pWhen, 0);
      if( SQLITE_OK==sqlite3ResolveExprNames(&sNC, pWhen) ){
        iEndTrigger = sqlite3VdbeMakeLabel(v);
        sqlite3ExprIfFalse(pSubParse, pWhen, iEndTrigger, SQLITE_JUMPIFNULL);
      }
      sqlite3ExprDelete(db, pWhen);
    }

    /* Code the trigger program into the sub-vdbe. */
    codeTriggerProgram(pSubParse, pTrigger->step_list, OE_Default);
    if( iEndTrigger ){
      sqlite3VdbeResolveLabel(v, iEndTrigger);
    }
    sqlite3VdbeAddOp0(v, OP_Halt);
    transferParseError(pParse, pSubParse);
    pProgram->aOp = sqlite3VdbeTakeOpArray(v, &pProgram->nOp, &pParse->nArg);
    pProgram->nMem = pSubParse->nMem;
    pProgram->nCsr = pSubParse->nTab;
    pProgram->token = (void *)pTrigger;
    pC->oldmask = pSubParse->oldmask;
    pC->newmask = pSubParse->newmask;
    sqlite3VdbeDelete(v);

    while( pSubParse->pAinc ){
      AutoincInfo *p = pSubParse->pAinc;
      pSubParse->pAinc = p->pNext;
      sqlite3DbFree(db, p);
    }
  }
  sqlite3StackFree(db, pSubParse);

  /* Pop the entry off the authorization stack */
  sqlite3AuthContextPop(&sContext);
  return pC;
}
    
static CodedTrigger *getRowTrigger(
  Parse *pParse,
  Trigger *pTrigger,   /* Trigger to code */
  int op,              /* One of TK_UPDATE, TK_INSERT, TK_DELETE */
  Table *pTab,         /* The table to code triggers from */
  int orconf
){
  CodedTrigger *pC;
  Parse *pRoot = pParse;

  /* It may be that this trigger has already been coded (or is in the
  ** process of being coded). If this is the case, then an entry with
  ** a matching CodedTrigger.pTrigger field will be present somewhere
  ** in the Parse.pCodedTrigger list. Search for such an entry.  */
  if( pParse->pRoot ){
    pRoot = pParse->pRoot;
  }
  for(pC=pRoot->pCodedTrigger; 
      pC && (pC->pTrigger!=pTrigger || pC->orconf!=orconf); 
      pC=pC->pNext
  );

  if( !pC ){
    pC = codeRowTrigger(pRoot, pParse, pTrigger, op, pTab, orconf);
  }

  return pC;
}

/*
** This is called to code FOR EACH ROW triggers.
**
** When the code that this function generates is executed, the following 
** must be true:

** are set to values that describe the columns used by the trigger program
** in the OLD.* and NEW.* tables respectively. If column N of the 
** pseudo-table is read at least once, the corresponding bit of the output
** mask is set. If a column with an index greater than 32 is read, the
** output mask is set to the special value 0xffffffff.
**
*/
void sqlite3CodeRowTrigger(
  Parse *pParse,       /* Parse context */
  Trigger *pTrigger,   /* List of triggers on table pTab */
  int op,              /* One of TK_UPDATE, TK_INSERT, TK_DELETE */
  ExprList *pChanges,  /* Changes list for any UPDATE OF triggers */
  int tr_tm,           /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
  Table *pTab,         /* The table to code triggers from */
  int newIdx,          /* The indice of the "new" row to access */
  int oldIdx,          /* The indice of the "old" row to access */
  int orconf,          /* ON CONFLICT policy */
  int ignoreJump       /* Instruction to jump to for RAISE(IGNORE) */


){
  Trigger *p;






  assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE);
  assert(tr_tm == TRIGGER_BEFORE || tr_tm == TRIGGER_AFTER );



  for(p=pTrigger; p; p=p->pNext){


    /* Sanity checking:  The schema for the trigger and for the table are
    ** always defined.  The trigger must be in the same schema as the table
    ** or else it must be a TEMP trigger. */
    assert( p->pSchema!=0 );
    assert( p->pTabSchema!=0 );
    assert( p->pSchema==p->pTabSchema 
         || p->pSchema==pParse->db->aDb[1].pSchema );

    /* Determine whether we should code this trigger */

    if( p->op==op 
     && p->tr_tm==tr_tm 
     && checkColumnOverlap(p->pColumns,pChanges)
    ){
      Vdbe *v = sqlite3GetVdbe(pParse); /* Main VM */
      CodedTrigger *pC;
      pC = getRowTrigger(pParse, p, op, pTab, orconf);
      assert( pC || pParse->nErr || pParse->db->mallocFailed );


      /* Code the OP_Program opcode in the parent VDBE. P4 of the OP_Program 
      ** is a pointer to the sub-vdbe containing the trigger program.  */

      if( pC ){
        sqlite3VdbeAddOp3(v, OP_Program, oldIdx, newIdx, ++pParse->nMem);
        pC->pProgram->nRef++;
        sqlite3VdbeChangeP4(v, -1, (const char *)pC->pProgram, P4_SUBPROGRAM);
        VdbeComment((v, "Call trigger: %s (%s)", p->zName,onErrorText(orconf)));
      }

    }
  }





}










void sqlite3TriggerUses(
  Parse *pParse,       /* Parse context */
  Trigger *pTrigger,   /* List of triggers on table pTab */
  int op,              /* One of TK_UPDATE, TK_INSERT, TK_DELETE */
  ExprList *pChanges,  /* Changes list for any UPDATE OF triggers */
  Table *pTab,         /* The table to code triggers from */
  int orconf,          /* Default ON CONFLICT policy for trigger steps */
  u32 *piOldColMask,   /* OUT: Mask of columns used from the OLD.* table */
  u32 *piNewColMask    /* OUT: Mask of columns used from the NEW.* table */
){
  Trigger *p;

  assert(op==TK_UPDATE || op==TK_INSERT || op==TK_DELETE);




  for(p=pTrigger; p; p=p->pNext){

    if( p->op==op && checkColumnOverlap(p->pColumns,pChanges) ){

      CodedTrigger *pC;
      pC = getRowTrigger(pParse, p, op, pTab, orconf);
      if( pC ){
        *piOldColMask |= pC->oldmask;
        *piNewColMask |= pC->newmask;
      }



    }

  }
}




#endif /* !defined(SQLITE_OMIT_TRIGGER) */

  int j1;                /* Addresses of jump instructions */
  int okOnePass;         /* True for one-pass algorithm without the FIFO */

#ifndef SQLITE_OMIT_TRIGGER
  int isView;                  /* Trying to update a view */
  Trigger *pTrigger;           /* List of triggers on pTab, if required */
#endif




  u32 old_col_mask = 0;        /* Mask of OLD.* columns in use */
  u32 new_col_mask = 0;        /* Mask of NEW.* columns in use */




  /* Register Allocations */
  int regRowCount = 0;   /* A count of rows changed */
  int regOldRowid;       /* The old rowid */
  int regNewRowid;       /* The new rowid */
  int regNew;
  int regOld;
  int regRowSet = 0;     /* Rowset of rows to be updated */

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

  if( sqlite3IsReadOnly(pParse, pTab, (pTrigger?1:0)) ){
    goto update_cleanup;
  }
  aXRef = sqlite3DbMallocRaw(db, sizeof(int) * pTab->nCol );
  if( aXRef==0 ) goto update_cleanup;
  for(i=0; i<pTab->nCol; i++) aXRef[i] = -1;









  /* Allocate a cursors for the main database table and for all indices.
  ** The index cursors might not be used, but if they are used they
  ** need to occur right after the database cursor.  So go ahead and
  ** allocate enough space, just in case.
  */
  pTabList->a[0].iCursor = iCur = pParse->nTab++;
  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){

          break;
        }
      }
    }
    aRegIdx[j] = reg;
  }

















  /* Begin generating code. */

  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto update_cleanup;
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, 1, iDb);

#ifndef SQLITE_OMIT_VIRTUALTABLE
  /* Virtual tables must be handled separately */
  if( IsVirtual(pTab) ){
    updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
                       pWhere);
    pWhere = 0;
    pTabList = 0;
    goto update_cleanup;
  }
#endif

  /* Allocate required registers. */




  regOldRowid = regNewRowid = ++pParse->nMem;


  if( pTrigger ){

    regOld = pParse->nMem + 1;
    pParse->nMem += pTab->nCol;
  }




  if( chngRowid || pTrigger ){
    regNewRowid = ++pParse->nMem;
  }



  regNew = pParse->nMem + 1;
  pParse->nMem += pTab->nCol;





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


  }



  /* If there are any triggers, set old_col_mask and new_col_mask. */
  sqlite3TriggerUses(pParse, 
      pTrigger, TK_UPDATE, pChanges, pTab, onError, &old_col_mask, &new_col_mask
  );

  /* If we are trying to update 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);

  /* End the database scan loop.
  */
  sqlite3WhereEnd(pWInfo);

  /* Initialize the count of updated rows
  */
  if( (db->flags & SQLITE_CountRows) && !pParse->pTriggerTab ){
    regRowCount = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
  }

  if( !isView ){
    /* 
    ** Open every index that needs updating.  Note that if any

        KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
        sqlite3VdbeAddOp4(v, OP_OpenWrite, iCur+i+1, pIdx->tnum, iDb,
                       (char*)pKey, P4_KEYINFO_HANDOFF);
        assert( pParse->nTab>iCur+i+1 );
      }
    }
  }






  /* Top of the update loop */
  if( okOnePass ){
    int a1 = sqlite3VdbeAddOp1(v, OP_NotNull, regOldRowid);
    addr = sqlite3VdbeAddOp0(v, OP_Goto);
    sqlite3VdbeJumpHere(v, a1);
  }else{
    addr = sqlite3VdbeAddOp3(v, OP_RowSetRead, regRowSet, 0, regOldRowid);
  }






  /* Make cursor iCur point to the record that is being updated. If

  ** this record does not exist for some reason (deleted by a trigger,
  ** for example, then jump to the next iteration of the RowSet loop.  */
  sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid);

  /* If there are triggers on this table, populate an array of registers 
  ** with the required old.* column data.  */




  if( pTrigger ){
    for(i=0; i<pTab->nCol; i++){
      if( aXRef[i]<0 || old_col_mask==0xffffffff || (old_col_mask & (1<<i)) ){




        sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regOld+i);
        sqlite3ColumnDefault(v, pTab, i, regOld+i);





      }else{
        sqlite3VdbeAddOp2(v, OP_Null, 0, regOld+i);
      }





    }







  }

  /* If the record number will change, set register regNewRowid to
  ** contain the new value. If the record number is not being modified,
  ** then regNewRowid is the same register as regOldRowid, which is
  ** already populated.  */
  assert( chngRowid || pTrigger || regOldRowid==regNewRowid );
  if( chngRowid ){
    sqlite3ExprCode(pParse, pRowidExpr, regNewRowid);
    sqlite3VdbeAddOp1(v, OP_MustBeInt, regNewRowid);
  }else if( pTrigger ){
    sqlite3VdbeAddOp2(v, OP_Copy, regOldRowid, regNewRowid);
  }

  /* Populate the array of registers beginning at regNew with the new
  ** row data. This array is used to check constaints, create the new
  ** table and index records, and as the values for any new.* references
  ** made by triggers.  */
  for(i=0; i<pTab->nCol; i++){
    if( i==pTab->iPKey ){
      sqlite3VdbeAddOp2(v, OP_Null, 0, regNew+i);

    }else{
      j = aXRef[i];
      if( j<0 ){
        sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regNew+i);
        sqlite3ColumnDefault(v, pTab, i, regNew+i);

      }else{

        sqlite3ExprCode(pParse, pChanges->a[j].pExpr, regNew+i);
      }
    }








  }








  /* Fire any BEFORE UPDATE triggers. This happens before constraints are

  ** verified. One could argue that this is wrong.  */
  sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges, 
      TRIGGER_BEFORE, pTab, regNew, regOld, onError, addr);







  if( !isView ){







    /* Do constraint checks. */

    sqlite3GenerateConstraintChecks(pParse, pTab, iCur, regNewRowid,
        aRegIdx, chngRowid, 1, onError, addr, 0);


    /* Delete the index entries associated with the current record.  */

    j1 = sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, regOldRowid);
    sqlite3GenerateRowIndexDelete(pParse, pTab, iCur, aRegIdx);
  
    /* If changing the record number, delete the old record.  */

    if( chngRowid ){
      sqlite3VdbeAddOp2(v, OP_Delete, iCur, 0);
    }
    sqlite3VdbeJumpHere(v, j1);
  
    /* Create the new index entries and the new record.  */

    sqlite3CompleteInsertion(pParse, pTab, iCur, regNewRowid, aRegIdx,1,-1,0,0);

  }

  /* Increment the row counter 
  */
  if( (db->flags & SQLITE_CountRows) && !pParse->pTriggerTab){
    sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
  }




  sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges, 



      TRIGGER_AFTER, pTab, regNew, regOld, onError, addr);

  /* Repeat the above with the next record to be updated, until
  ** all record selected by the WHERE clause have been updated.
  */
  sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
  sqlite3VdbeJumpHere(v, addr);

  /* Close all tables */
  for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
    if( openAll || aRegIdx[i]>0 ){
      sqlite3VdbeAddOp2(v, OP_Close, iCur+i+1, 0);
    }
  }
  sqlite3VdbeAddOp2(v, OP_Close, iCur, 0);





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

update_cleanup:
  sqlite3AuthContextPop(&sContext);

** If P4 is not null then it is an error message string.
**
** There is an implied "Halt 0 0 0" instruction inserted at the very end of
** every program.  So a jump past the last instruction of the program
** is the same as executing Halt.
*/
case OP_Halt: {
  if( pOp->p1==SQLITE_OK && p->pFrame ){
    VdbeFrame *pFrame = p->pFrame;
    p->pFrame = pFrame->pParent;
    p->nFrame--;
    pc = sqlite3VdbeFrameRestore(pFrame);
    if( pOp->p2==OE_Ignore ){
    }
    break;
  }
  p->rc = pOp->p1;

  p->errorAction = (u8)pOp->p2;
  p->pc = pc;
  if( pOp->p4.z ){
    sqlite3SetString(&p->zErrMsg, db, "%s", pOp->p4.z);
  }
  rc = sqlite3VdbeHalt(p);
  assert( rc==SQLITE_BUSY || rc==SQLITE_OK );
  if( rc==SQLITE_BUSY ){
    p->rc = rc = SQLITE_BUSY;

  Context *pContext;
  pContext = &p->contextStack[--p->contextStackTop];
  assert( p->contextStackTop>=0 );
  db->lastRowid = pContext->lastRowid;
  p->nChange = pContext->nChange;
  break;
}

/* Opcode: Program P1 P2 P3 P4 *
**
** Execute a trigger program. P1 contains the address of the memory cell
** that contains the left-most column of the old.* table (unless the trigger
** program is firing as a result of an INSERT statement). P2 is the address 
** of the corresponding column in the new.* table (unless the trigger 
** program is being fired due to a DELETE).
**
** Register P3 contains the address of a memory cell in this (the parent)
** VM that is used to allocate the memory required by the sub-vdbe at 
** runtime.
**
** P4 is a pointer to the VM containing the trigger program.
*/
case OP_Program: {
  VdbeFrame *pFrame;
  SubProgram *pProgram = pOp->p4.pProgram;
  Mem *pRt = &p->aMem[pOp->p3];        /* Register to allocate runtime space */
  assert( pProgram->nOp>0 );
  
  /* If noRecTrigger is true, then recursive invocation of triggers is
  ** disabled for backwards compatibility. 
  ** 
  ** It is recursive invocation of triggers, at the SQL level, that is 
  ** disabled. In some cases a single trigger may generate more than one 
  ** SubProgram (if the trigger may be executed with more than one different 
  ** ON CONFLICT algorithm). SubProgram structures associated with a
  ** single trigger all have the same value for the SubProgram.token 
  ** variable.
  */
  if( 1 || p->noRecTrigger ){
    void *t = pProgram->token;
    for(pFrame=p->pFrame; pFrame && pFrame->token!=t; pFrame=pFrame->pParent);
    if( pFrame ) break;
  }

  /* TODO: This constant should be configurable. */
  if( p->nFrame>1000 ){
    rc = SQLITE_ERROR;
    sqlite3SetString(&p->zErrMsg, db, "too many levels of trigger recursion");
    break;
  }

  /* Register pRt is used to store the memory required to save the state
  ** of the current program, and the memory required at runtime to execute
  ** the trigger program. If this trigger has been fired before, then pRt 
  ** is already allocated. Otherwise, it must be initialized.  */
  if( (pRt->flags&MEM_Frame)==0 ){
    Mem *pMem;
    Mem *pEnd;

    /* SubProgram.nMem is set to the number of memory cells used by the 
    ** program stored in SubProgram.aOp. As well as these, one memory
    ** cell is required for each cursor used by the program. Set local
    ** variable nMem (and later, VdbeFrame.nChildMem) to this value.
    */
    int nMem = pProgram->nMem + pProgram->nCsr;
    int nByte = ROUND8(sizeof(VdbeFrame))
              + nMem * sizeof(Mem)
              + pProgram->nCsr * sizeof(VdbeCursor *);
    pFrame = sqlite3DbMallocZero(db, nByte);
    if( !pFrame ){
      goto no_mem;
    }
    sqlite3VdbeMemRelease(pRt);
    pRt->flags = MEM_Frame;
    pRt->u.pFrame = pFrame;

    pFrame->v = p;
    pFrame->nChildMem = nMem;
    pFrame->nChildCsr = pProgram->nCsr;
    pFrame->pc = pc;
    pFrame->aMem = p->aMem;
    pFrame->nMem = p->nMem;
    pFrame->apCsr = p->apCsr;
    pFrame->nCursor = p->nCursor;
    pFrame->aOp = p->aOp;
    pFrame->nOp = p->nOp;
    pFrame->token = pProgram->token;

    pEnd = &VdbeFrameMem(pFrame)[pFrame->nChildMem];
    for(pMem=VdbeFrameMem(pFrame); pMem!=pEnd; pMem++){
      pMem->flags = MEM_Null;
      pMem->db = db;
    }
  }else{
    pFrame = pRt->u.pFrame;
    assert( pProgram->nMem+pProgram->nCsr==pFrame->nChildMem );
    assert( pProgram->nCsr==pFrame->nChildCsr );
    assert( pc==pFrame->pc );
  }

  p->nFrame++;
  pFrame->pParent = p->pFrame;
  p->pFrame = pFrame;
  p->aMem = &VdbeFrameMem(pFrame)[-1];
  p->nMem = pFrame->nChildMem;
  p->nCursor = pFrame->nChildCsr;
  p->apCsr = (VdbeCursor **)&p->aMem[p->nMem+1];
  p->aOp = pProgram->aOp;
  p->nOp = pProgram->nOp;
  pc = -1;

  break;
}

/* Opcode: TriggerVal P1 P2 P3 * *
**
** Copy a value currently stored in a memory cell of the parent VM to
** a cell in this VMs address space. This is used by trigger programs
** to access the new.* and old.* values.
**
** If parameter P3 is non-zero, then the value read is from the new.*
** table. If P3 is zero, then the value is read from the old.* table.
** Parameter P1 is the index of the required new.* or old.* column (or
** -1 for rowid). 
**
** Parameter P2 is the index of the memory cell in this VM to copy the 
** value to.
*/
case OP_TriggerVal: {           /* out2-prerelease */
  VdbeFrame *pF = p->pFrame;
  Mem *pIn;
  int iFrom = pOp->p1;           /* Memory cell in parent frame */
  iFrom += (pOp->p3 ? pF->aOp[pF->pc].p2 : pF->aOp[pF->pc].p1);
  pIn = &pF->aMem[iFrom];
  sqlite3VdbeMemShallowCopy(pOut, pIn, MEM_Ephem);
  break;
}

#endif /* #ifndef SQLITE_OMIT_TRIGGER */

#ifndef SQLITE_OMIT_AUTOINCREMENT
/* Opcode: MemMax P1 P2 * * *
**
** Set the value of register P1 to the maximum of its current value
** and the value in register P2.

/*
** The names of the following types declared in vdbeInt.h are required
** for the VdbeOp definition.
*/
typedef struct VdbeFunc VdbeFunc;
typedef struct Mem Mem;
typedef struct SubProgram SubProgram;

/*
** A single instruction of the virtual machine has an opcode
** and as many as three operands.  The instruction is recorded
** as an instance of the following structure:
*/
struct VdbeOp {
  u8 opcode;          /* What operation to perform */
  signed char p4type; /* One of the P4_xxx constants for p4 */
  u8 opflags;         /* Not currently used */
  u8 p5;              /* Fifth parameter is an unsigned character */
  int p1;             /* First operand */
  int p2;             /* Second parameter (often the jump destination) */
  int p3;             /* The third parameter */
  union {             /* fourth parameter */
    int i;                 /* Integer value if p4type==P4_INT32 */
    void *p;               /* Generic pointer */
    char *z;               /* Pointer to data for string (char array) types */
    i64 *pI64;             /* Used when p4type is P4_INT64 */
    double *pReal;         /* Used when p4type is P4_REAL */
    FuncDef *pFunc;        /* Used when p4type is P4_FUNCDEF */
    VdbeFunc *pVdbeFunc;   /* Used when p4type is P4_VDBEFUNC */
    CollSeq *pColl;        /* Used when p4type is P4_COLLSEQ */
    Mem *pMem;             /* Used when p4type is P4_MEM */
    VTable *pVtab;         /* Used when p4type is P4_VTAB */
    KeyInfo *pKeyInfo;     /* Used when p4type is P4_KEYINFO */
    int *ai;               /* Used when p4type is P4_INTARRAY */
    SubProgram *pProgram;  /* Used when p4type is P4_SUBPROGRAM */
  } p4;
#ifdef SQLITE_DEBUG
  char *zComment;          /* Comment to improve readability */
#endif
#ifdef VDBE_PROFILE
  int cnt;                 /* Number of times this instruction was executed */
  u64 cycles;              /* Total time spent executing this instruction */
#endif
};
typedef struct VdbeOp VdbeOp;


/*
** A sub-routine used to implement a trigger program.
*/
struct SubProgram {
  VdbeOp *aOp;                  /* Array of opcodes for sub-program */
  int nOp;                      /* Elements in aOp[] */
  int nMem;                     /* Number of memory cells required */
  int nCsr;                     /* Number of cursors required */
  int nRef;                     /* Number of pointers to this structure */
  void *token;                  /* id that may be used to recursive triggers */
};

/*
** A smaller version of VdbeOp used for the VdbeAddOpList() function because
** it takes up less space.
*/
struct VdbeOpList {
  u8 opcode;          /* What operation to perform */
  signed char p1;     /* First operand */
  signed char p2;     /* Second parameter (often the jump destination) */
  signed char p3;     /* Third parameter */
};
typedef struct VdbeOpList VdbeOpList;

/*
** Allowed values of VdbeOp.p4type
*/
#define P4_NOTUSED    0   /* The P4 parameter is not used */
#define P4_DYNAMIC  (-1)  /* Pointer to a string obtained from sqliteMalloc() */
#define P4_STATIC   (-2)  /* Pointer to a static string */
#define P4_COLLSEQ  (-4)  /* P4 is a pointer to a CollSeq structure */
#define P4_FUNCDEF  (-5)  /* P4 is a pointer to a FuncDef structure */
#define P4_KEYINFO  (-6)  /* P4 is a pointer to a KeyInfo structure */
#define P4_VDBEFUNC (-7)  /* P4 is a pointer to a VdbeFunc structure */
#define P4_MEM      (-8)  /* P4 is a pointer to a Mem*    structure */
#define P4_TRANSIENT (-9) /* P4 is a pointer to a transient string */
#define P4_VTAB     (-10) /* P4 is a pointer to an sqlite3_vtab structure */
#define P4_MPRINTF  (-11) /* P4 is a string obtained from sqlite3_mprintf() */
#define P4_REAL     (-12) /* P4 is a 64-bit floating point value */
#define P4_INT64    (-13) /* P4 is a 64-bit signed integer */
#define P4_INT32    (-14) /* P4 is a 32-bit signed integer */
#define P4_INTARRAY (-15) /* P4 is a vector of 32-bit integers */
#define P4_SUBPROGRAM  (-18) /* P4 is a pointer to a SubProgram structure */

/* When adding a P4 argument using P4_KEYINFO, a copy of the KeyInfo structure
** is made.  That copy is freed when the Vdbe is finalized.  But if the
** argument is P4_KEYINFO_HANDOFF, the passed in pointer is used.  It still
** gets freed when the Vdbe is finalized so it still should be obtained
** from a single sqliteMalloc().  But no copy is made and the calling
** function should *not* try to free the KeyInfo.

void sqlite3VdbeJumpHere(Vdbe*, int addr);
void sqlite3VdbeChangeToNoop(Vdbe*, int addr, int N);
void sqlite3VdbeChangeP4(Vdbe*, int addr, const char *zP4, int N);
void sqlite3VdbeUsesBtree(Vdbe*, int);
VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);
int sqlite3VdbeMakeLabel(Vdbe*);
void sqlite3VdbeDelete(Vdbe*);
void sqlite3VdbeMakeReady(Vdbe*,int,int,int,int,int);
int sqlite3VdbeFinalize(Vdbe*);
void sqlite3VdbeResolveLabel(Vdbe*, int);
int sqlite3VdbeCurrentAddr(Vdbe*);
#ifdef SQLITE_DEBUG
  void sqlite3VdbeTrace(Vdbe*,FILE*);
#endif
void sqlite3VdbeResetStepResult(Vdbe*);
int sqlite3VdbeReset(Vdbe*);
void sqlite3VdbeSetNumCols(Vdbe*,int);
int sqlite3VdbeSetColName(Vdbe*, int, int, const char *, void(*)(void*));
void sqlite3VdbeCountChanges(Vdbe*);
sqlite3 *sqlite3VdbeDb(Vdbe*);
void sqlite3VdbeSetSql(Vdbe*, const char *z, int n, int);
void sqlite3VdbeSwap(Vdbe*,Vdbe*);
VdbeOp *sqlite3VdbeTakeOpArray(Vdbe*, int*, int*);
void sqlite3VdbeProgramDelete(sqlite3 *, SubProgram *, int);

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
int sqlite3VdbeReleaseMemory(int);
#endif
UnpackedRecord *sqlite3VdbeRecordUnpack(KeyInfo*,int,const void*,char*,int);
void sqlite3VdbeDeleteUnpackedRecord(UnpackedRecord*);
int sqlite3VdbeRecordCompare(int,const void*,UnpackedRecord*);

  int payloadSize;      /* Total number of bytes in the record */
  u32 *aType;           /* Type values for all entries in the record */
  u32 *aOffset;         /* Cached offsets to the start of each columns data */
  u8 *aRow;             /* Data for the current row, if all on one page */
};
typedef struct VdbeCursor VdbeCursor;

typedef struct VdbeFrame VdbeFrame;
struct VdbeFrame {
  Vdbe *v;                /* VM this frame belongs to */
  int pc;                 /* Program Counter */
  Op *aOp;                /* Program instructions */
  int nOp;                /* Size of aOp array */
  Mem *aMem;              /* Array of memory cells */
  int nMem;               /* Number of entries in aMem */
  VdbeCursor **apCsr;     /* Element of Vdbe cursors */
  u16 nCursor;            /* Number of entries in apCsr */
  VdbeFrame *pParent;     /* Parent of this frame */
  void *token;            /* Copy of SubProgram.token */
  int nChildMem;          /* Number of memory cells for child frame */
  int nChildCsr;          /* Number of cursors for child frame */
};

#define VdbeFrameMem(p) ((Mem *)&((u8 *)p)[ROUND8(sizeof(VdbeFrame))])

/*
** A value for VdbeCursor.cacheValid that means the cache is always invalid.
*/
#define CACHE_STALE 0

/*
** Internally, the vdbe manipulates nearly all SQL values as Mem

*/
struct Mem {
  union {
    i64 i;              /* Integer value. */
    int nZero;          /* Used when bit MEM_Zero is set in flags */
    FuncDef *pDef;      /* Used only when flags==MEM_Agg */
    RowSet *pRowSet;    /* Used only when flags==MEM_RowSet */
    VdbeFrame *pFrame;  /* Used when flags==MEM_Frame */
  } u;
  double r;           /* Real value */
  sqlite3 *db;        /* The associated database connection */
  char *z;            /* String or BLOB value */
  int n;              /* Number of characters in string value, excluding '\0' */
  u16 flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
  u8  type;           /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */

*/
#define MEM_Null      0x0001   /* Value is NULL */
#define MEM_Str       0x0002   /* Value is a string */
#define MEM_Int       0x0004   /* Value is an integer */
#define MEM_Real      0x0008   /* Value is a real number */
#define MEM_Blob      0x0010   /* Value is a BLOB */
#define MEM_RowSet    0x0020   /* Value is a RowSet object */
#define MEM_Frame     0x0040   /* Value is a VdbeFrame object */
#define MEM_TypeMask  0x00ff   /* Mask of type bits */

/* Whenever Mem contains a valid string or blob representation, one of
** the following flags must be set to determine the memory management
** policy for Mem.z.  The MEM_Term flag tells us whether or not the
** string is \000 or \u0000 terminated
*/

  int aCounter[2];        /* Counters used by sqlite3_stmt_status() */
  char *zSql;             /* Text of the SQL statement that generated this */
  void *pFree;            /* Free this when deleting the vdbe */
  int iStatement;         /* Statement number (or 0 if has not opened stmt) */
#ifdef SQLITE_DEBUG
  FILE *trace;            /* Write an execution trace here, if not NULL */
#endif
  VdbeFrame *pFrame;      /* Parent frame */
  int nFrame;             /* Number of frames in pFrame list */
  u8 noRecTrigger;        /* True to disable recursive triggers */
};

/*
** The following are allowed values for Vdbe.magic
*/
#define VDBE_MAGIC_INIT     0x26bceaa5    /* Building a VDBE program */
#define VDBE_MAGIC_RUN      0xbdf20da3    /* VDBE is ready to execute */

void sqlite3VdbeMemRelease(Mem *p);
void sqlite3VdbeMemReleaseExternal(Mem *p);
int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
const char *sqlite3OpcodeName(int);
int sqlite3VdbeOpcodeHasProperty(int, int);
int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
int sqlite3VdbeCloseStatement(Vdbe *, int);
void sqlite3VdbeFrameDelete(VdbeFrame*);
int sqlite3VdbeFrameRestore(VdbeFrame *);
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
int sqlite3VdbeReleaseBuffers(Vdbe *p);
#endif

#ifndef SQLITE_OMIT_SHARED_CACHE
void sqlite3VdbeMutexArrayEnter(Vdbe *p);
#else

  int rc;
  if( pStmt==0 ){
    rc = SQLITE_OK;
  }else{
    Vdbe *v = (Vdbe*)pStmt;
    sqlite3_mutex_enter(v->db->mutex);
    rc = sqlite3VdbeReset(v);
    sqlite3VdbeMakeReady(v, -1, 0, 0, 0, 0);
    assert( (rc & (v->db->errMask))==rc );
    rc = sqlite3ApiExit(v->db, rc);
    sqlite3_mutex_leave(v->db->mutex);
  }
  return rc;
}

**
** If no such instruction is found, then every Statement instruction 
** is changed to a Noop.  In this way, we avoid creating the statement 
** journal file unnecessarily.
*/
static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs){
  int i;
  int nMaxArgs = *pMaxFuncArgs;
  Op *pOp;
  int *aLabel = p->aLabel;
  int doesStatementRollback = 0;
  int hasStatementBegin = 0;
  p->readOnly = 1;
  p->usesStmtJournal = 0;
  for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){

/*
** Return the address of the next instruction to be inserted.
*/
int sqlite3VdbeCurrentAddr(Vdbe *p){
  assert( p->magic==VDBE_MAGIC_INIT );
  return p->nOp;
}

VdbeOp *sqlite3VdbeTakeOpArray(Vdbe *p, int *pnOp, int *pnMaxArg){
  VdbeOp *aOp = p->aOp;
  resolveP2Values(p, pnMaxArg);
  *pnOp = p->nOp;
  p->aOp = 0;
  return aOp;
}

/*
** Add a whole list of operations to the operation stack.  Return the
** address of the first operation added.
*/
int sqlite3VdbeAddOpList(Vdbe *p, int nOp, VdbeOpList const *aOp){
  int addr;

        sqlite3ValueFree((sqlite3_value*)p4);
        break;
      }
      case P4_VTAB : {
        sqlite3VtabUnlock((VTable *)p4);
        break;
      }
      case P4_SUBPROGRAM : {
        sqlite3VdbeProgramDelete(db, (SubProgram *)p4, 1);
        break;
      }
    }
  }
}

static void vdbeFreeOpArray(sqlite3 *db, Op *aOp, int nOp){
  if( aOp ){
    Op *pOp;
    for(pOp=aOp; pOp<&aOp[nOp]; pOp++){
      freeP4(db, pOp->p4type, pOp->p4.p);
#ifdef SQLITE_DEBUG
      sqlite3DbFree(db, pOp->zComment);
#endif     
    }
  }
  sqlite3DbFree(db, aOp);
}

void sqlite3VdbeProgramDelete(sqlite3 *db, SubProgram *p, int freeop){
  assert( p->nRef>0 );
  if( freeop || p->nRef==1 ){
    Op *aOp = p->aOp;
    p->aOp = 0;
    vdbeFreeOpArray(db, aOp, p->nOp);
    p->nOp = 0;
  }
  p->nRef--;
  if( p->nRef==0 ){
    sqlite3DbFree(db, p);
  }
}


/*
** Change N opcodes starting at addr to No-ops.
*/
void sqlite3VdbeChangeToNoop(Vdbe *p, int addr, int N){
  if( p->aOp ){

** Change the comment on the the most recently coded instruction.  Or
** insert a No-op and add the comment to that new instruction.  This
** makes the code easier to read during debugging.  None of this happens
** in a production build.
*/
void sqlite3VdbeComment(Vdbe *p, const char *zFormat, ...){
  va_list ap;
  if( !p ) return;
  assert( p->nOp>0 || p->aOp==0 );
  assert( p->aOp==0 || p->aOp[p->nOp-1].zComment==0 || p->db->mallocFailed );
  if( p->nOp ){
    char **pz = &p->aOp[p->nOp-1].zComment;
    va_start(ap, zFormat);
    sqlite3DbFree(p->db, *pz);
    *pz = sqlite3VMPrintf(p->db, zFormat, ap);
    va_end(ap);
  }
}
void sqlite3VdbeNoopComment(Vdbe *p, const char *zFormat, ...){
  va_list ap;
  if( !p ) return;
  sqlite3VdbeAddOp0(p, OP_Noop);
  assert( p->nOp>0 || p->aOp==0 );
  assert( p->aOp==0 || p->aOp[p->nOp-1].zComment==0 || p->db->mallocFailed );
  if( p->nOp ){
    char **pz = &p->aOp[p->nOp-1].zComment;
    va_start(ap, zFormat);
    sqlite3DbFree(p->db, *pz);

      sqlite3_snprintf(nTemp, zTemp, "vtab:%p:%p", pVtab, pVtab->pModule);
      break;
    }
#endif
    case P4_INTARRAY: {
      sqlite3_snprintf(nTemp, zTemp, "intarray");
      break;
    }
    case P4_SUBPROGRAM: {
      sqlite3_snprintf(nTemp, zTemp, "program");
      break;
    }
    default: {
      zP4 = pOp->p4.z;
      if( zP4==0 ){
        zP4 = zTemp;
        zTemp[0] = 0;
      }

      ** callgrind, this causes a certain test case to hit the CPU 4.7 
      ** percent less (x86 linux, gcc version 4.1.2, -O6) than if 
      ** sqlite3MemRelease() were called from here. With -O2, this jumps
      ** to 6.6 percent. The test case is inserting 1000 rows into a table 
      ** with no indexes using a single prepared INSERT statement, bind() 
      ** and reset(). Inserts are grouped into a transaction.
      */
      if( p->flags&(MEM_Agg|MEM_Dyn|MEM_Frame|MEM_RowSet) ){
        sqlite3VdbeMemRelease(p);
      }else if( p->zMalloc ){
        sqlite3DbFree(db, p->zMalloc);
        p->zMalloc = 0;
      }

      p->flags = MEM_Null;
    }
    db->mallocFailed = malloc_failed;
  }
}

void sqlite3VdbeFrameDelete(VdbeFrame *p){
  int i;
  Mem *aMem = VdbeFrameMem(p);
  VdbeCursor **apCsr = (VdbeCursor **)&aMem[p->nChildMem];
  for(i=0; i<p->nChildCsr; i++){
    sqlite3VdbeFreeCursor(p->v, apCsr[i]);
  }
  releaseMemArray(aMem, p->nChildMem);
  sqlite3DbFree(p->v->db, p);
}


#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
int sqlite3VdbeReleaseBuffers(Vdbe *p){
  int ii;
  int nFree = 0;
  assert( sqlite3_mutex_held(p->db->mutex) );
  for(ii=1; ii<=p->nMem; ii++){

** p->explain==2, only OP_Explain instructions are listed and these
** are shown in a different format.  p->explain==2 is used to implement
** EXPLAIN QUERY PLAN.
*/
int sqlite3VdbeList(
  Vdbe *p                   /* The VDBE */
){
  int nRow;                            /* Total number of rows to return */
  int nSub = 0;                        /* Number of sub-vdbes seen so far */
  SubProgram **apSub = 0;              /* Array of sub-vdbes */
  Mem *pSub = 0;
  sqlite3 *db = p->db;
  int i;
  int rc = SQLITE_OK;
  Mem *pMem = p->pResultSet = &p->aMem[1];

  assert( p->explain );
  assert( p->magic==VDBE_MAGIC_RUN );
  assert( db->magic==SQLITE_MAGIC_BUSY );
  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY || p->rc==SQLITE_NOMEM );

  /* Even though this opcode does not use dynamic strings for
  ** the result, result columns may become dynamic if the user calls
  ** sqlite3_column_text16(), causing a translation to UTF-16 encoding.
  */
  releaseMemArray(pMem, 8);

  if( p->rc==SQLITE_NOMEM ){
    /* This happens if a malloc() inside a call to sqlite3_column_text() or
    ** sqlite3_column_text16() failed.  */
    db->mallocFailed = 1;
    return SQLITE_ERROR;
  }

  /* Figure out total number of rows that will be returned by this 
  ** EXPLAIN program.  */
  nRow = p->nOp;
  if( p->explain==1 ){
    pSub = &p->aMem[9];
    if( pSub->flags&MEM_Blob ){
      nSub = pSub->n/sizeof(Vdbe*);
      apSub = (SubProgram **)pSub->z;
    }
    for(i=0; i<nSub; i++){
      nRow += apSub[i]->nOp;
    }
  }

  do{
    i = p->pc++;
  }while( i<nRow && p->explain==2 && p->aOp[i].opcode!=OP_Explain );
  if( i>=nRow ){
    p->rc = SQLITE_OK;
    rc = SQLITE_DONE;
  }else if( db->u1.isInterrupted ){
    p->rc = SQLITE_INTERRUPT;
    rc = SQLITE_ERROR;
    sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3ErrStr(p->rc));
  }else{
    char *z;
    Op *pOp;
    if( i<p->nOp ){
      pOp = &p->aOp[i];
    }else{
      int j;
      i -= p->nOp;
      for(j=0; i>=apSub[j]->nOp; j++){
        i -= apSub[j]->nOp;
      }
      pOp = &apSub[j]->aOp[i];
    }
    if( p->explain==1 ){
      pMem->flags = MEM_Int;
      pMem->type = SQLITE_INTEGER;
      pMem->u.i = i;                                /* Program counter */
      pMem++;
  
      pMem->flags = MEM_Static|MEM_Str|MEM_Term;
      pMem->z = (char*)sqlite3OpcodeName(pOp->opcode);  /* Opcode */
      assert( pMem->z!=0 );
      pMem->n = sqlite3Strlen30(pMem->z);
      pMem->type = SQLITE_TEXT;
      pMem->enc = SQLITE_UTF8;
      pMem++;

      if( pOp->p4type==P4_SUBPROGRAM ){
        int nByte = (nSub+1)*sizeof(SubProgram*);
        int j;
        for(j=0; j<nSub; j++){
          if( apSub[j]==pOp->p4.pProgram ) break;
        }
        if( j==nSub && SQLITE_OK==sqlite3VdbeMemGrow(pSub, nByte, 1) ){
          apSub = (SubProgram **)pSub->z;
          apSub[nSub++] = pOp->p4.pProgram;
          pSub->flags |= MEM_Blob;
          pSub->n = nSub*sizeof(SubProgram*);
        }
      }
    }

    pMem->flags = MEM_Int;
    pMem->u.i = pOp->p1;                          /* P1 */
    pMem->type = SQLITE_INTEGER;
    pMem++;

** is passed -1 and nMem, nCursor and isExplain are all passed zero.
*/
void sqlite3VdbeMakeReady(
  Vdbe *p,                       /* The VDBE */
  int nVar,                      /* Number of '?' see in the SQL statement */
  int nMem,                      /* Number of memory cells to allocate */
  int nCursor,                   /* Number of cursors to allocate */
  int nArg,                      /* Maximum number of args in SubPrograms */
  int isExplain                  /* True if the EXPLAIN keywords is present */
){
  int n;
  sqlite3 *db = p->db;

  assert( p!=0 );
  assert( p->magic==VDBE_MAGIC_INIT );

  ** first time this function is called for a given VDBE, not when it is
  ** being called from sqlite3_reset() to reset the virtual machine.
  */
  if( nVar>=0 && ALWAYS(db->mallocFailed==0) ){
    u8 *zCsr = (u8 *)&p->aOp[p->nOp];
    u8 *zEnd = (u8 *)&p->aOp[p->nOpAlloc];
    int nByte;

    resolveP2Values(p, &nArg);
    if( isExplain && nMem<10 ){
      nMem = 10;
    }
    memset(zCsr, 0, zEnd-zCsr);
    zCsr += (zCsr - (u8*)0)&7;
    assert( EIGHT_BYTE_ALIGNMENT(zCsr) );

    p->inVtabMethod = 0;
  }
#endif
  if( !pCx->ephemPseudoTable ){
    sqlite3DbFree(p->db, pCx->pData);
  }
}

int sqlite3VdbeFrameRestore(VdbeFrame *pFrame){
  Vdbe *v = pFrame->v;
  v->aOp = pFrame->aOp;
  v->nOp = pFrame->nOp;
  v->aMem = pFrame->aMem;
  v->nMem = pFrame->nMem;
  v->apCsr = pFrame->apCsr;
  v->nCursor = pFrame->nCursor;
  return pFrame->pc;
}

/*
** Close all cursors. 
**
** Also release any dynamic memory held by the VM in the Vdbe.aMem memory 
** cell array. This is necessary as the memory cell array may contain
** pointers to VdbeFrame objects, which may in turn contain pointers to
** open cursors.
*/
static void closeAllCursors(Vdbe *p){
  int i;
  /* if( p->apCsr==0 ) return; */

  if( p->pFrame ){
    VdbeFrame *pFrame = p->pFrame;
    for(pFrame=p->pFrame; pFrame->pParent; pFrame=pFrame->pParent);
    sqlite3VdbeFrameRestore(pFrame);
  }
  p->pFrame = 0;
  p->nFrame = 0;

  for(i=0; i<p->nCursor; i++){
    VdbeCursor *pC = p->apCsr[i];
    if( pC ){
      sqlite3VdbeFreeCursor(p, pC);
      p->apCsr[i] = 0;
    }
  }
  releaseMemArray(&p->aMem[1], p->nMem);
}

/*
** Clean up the VM after execution.
**
** This routine will automatically close any cursors, lists, and/or
** sorters that were left open.  It also deletes the values of
** variables in the aVar[] array.
*/
static void Cleanup(Vdbe *p){

  sqlite3 *db = p->db;






#ifdef SQLITE_DEBUG
  /* Execute assert() statements to ensure that the Vdbe.apCsr[] and 
  ** Vdbe.aMem[] arrays have already been cleaned up.  */
  int i;
  for(i=0; i<p->nCursor; i++){ assert( p->apCsr[i]==0 ); }
  for(i=1; i<=p->nMem; i++){ assert( p->aMem[i].flags==MEM_Null ); }
#endif


  if( p->contextStack ){
    sqlite3DbFree(db, p->contextStack);
  }
  p->contextStack = 0;
  p->contextStackDepth = 0;
  p->contextStackTop = 0;
  sqlite3DbFree(db, p->zErrMsg);

  }
}

/*
** Delete an entire VDBE.
*/
void sqlite3VdbeDelete(Vdbe *p){

  sqlite3 *db;

  if( NEVER(p==0) ) return;
  db = p->db;
  if( p->pPrev ){
    p->pPrev->pNext = p->pNext;
  }else{
    assert( db->pVdbe==p );
    db->pVdbe = p->pNext;
  }
  if( p->pNext ){
    p->pNext->pPrev = p->pPrev;
  }









  releaseMemArray(p->aVar, p->nVar);

  releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);
  vdbeFreeOpArray(db, p->aOp, p->nOp);
  sqlite3DbFree(db, p->aLabel);
  sqlite3DbFree(db, p->aColName);
  sqlite3DbFree(db, p->zSql);
  p->magic = VDBE_MAGIC_DEAD;

  sqlite3DbFree(db, p->pFree);
  sqlite3DbFree(db, p);
}

/*
** Make sure the cursor p is ready to read or write the row to which it
** was last positioned.  Return an error code if an OOM fault or I/O error

      ** always return an SQL NULL. This is useful because it means
      ** we can invoke OP_Column to fill in the vdbe cursors type 
      ** and offset cache without causing any IO.
      */
      sqlite3VdbeChangeP4(v, 3+flags, SQLITE_INT_TO_PTR(pTab->nCol+1),P4_INT32);
      sqlite3VdbeChangeP2(v, 7, pTab->nCol);
      if( !db->mallocFailed ){
        sqlite3VdbeMakeReady(v, 1, 1, 1, 0, 0);
      }
    }
   
    sqlite3BtreeLeaveAll(db);
    rc = sqlite3SafetyOff(db);
    if( NEVER(rc!=SQLITE_OK) || db->mallocFailed ){
      goto blob_open_out;

/*
** If the memory cell contains a string value that must be freed by
** invoking an external callback, free it now. Calling this function
** does not free any Mem.zMalloc buffer.
*/
void sqlite3VdbeMemReleaseExternal(Mem *p){
  assert( p->db==0 || sqlite3_mutex_held(p->db->mutex) );
  if( p->flags&(MEM_Agg|MEM_Dyn|MEM_RowSet|MEM_Frame) ){
    if( p->flags&MEM_Agg ){
      sqlite3VdbeMemFinalize(p, p->u.pDef);
      assert( (p->flags & MEM_Agg)==0 );
      sqlite3VdbeMemRelease(p);
    }else if( p->flags&MEM_Dyn && p->xDel ){
      assert( (p->flags&MEM_RowSet)==0 );
      p->xDel((void *)p->z);
      p->xDel = 0;
    }else if( p->flags&MEM_RowSet ){
      sqlite3RowSetClear(p->u.pRowSet);
    }else if( p->flags&MEM_Frame ){
      sqlite3VdbeFrameDelete(p->u.pFrame);
      p->flags &= ~MEM_Frame;
    }
  }
}

/*
** Release any memory held by the Mem. This may leave the Mem in an
** inconsistent state, for example with (Mem.z==0) and

  return SQLITE_OK;
}

/*
** Delete any previous value and set the value stored in *pMem to NULL.
*/
void sqlite3VdbeMemSetNull(Mem *pMem){
  if( pMem->flags & MEM_Frame ){
    sqlite3VdbeFrameDelete(pMem->u.pFrame);
  }
  if( pMem->flags & MEM_RowSet ){
    sqlite3RowSetClear(pMem->u.pRowSet);
  }
  MemSetTypeFlag(pMem, MEM_Null);
  pMem->type = SQLITE_NULL;
}

** array so that an OP_VBegin will get generated for it.  Add pTab to the
** array if it is missing.  If pTab is already in the array, this routine
** is a no-op.
*/
void sqlite3VtabMakeWritable(Parse *pParse, Table *pTab){
  int i, n;
  Table **apVtabLock;
  Parse *pRoot = (pParse->pRoot ? pParse->pRoot : pParse);

  assert( IsVirtual(pTab) );
  for(i=0; i<pRoot->nVtabLock; i++){
    if( pTab==pRoot->apVtabLock[i] ) return;
  }
  n = (pRoot->nVtabLock+1)*sizeof(pRoot->apVtabLock[0]);
  apVtabLock = sqlite3_realloc(pRoot->apVtabLock, n);
  if( apVtabLock ){
    pRoot->apVtabLock = apVtabLock;
    pRoot->apVtabLock[pRoot->nVtabLock++] = pTab;
  }else{
    pRoot->db->mallocFailed = 1;
  }
}

#endif /* SQLITE_OMIT_VIRTUALTABLE */

do_test attach3-12.9 {
  execsql {
    ATTACH DATABASE '' AS NULL
  }
  db_list
} {main temp {}}
do_test attach3-12.10 {
breakpoint
  execsql {
    DETACH ?
  }
  db_list
} {main temp}
do_test attach3-12.11 {
  catchsql {

# If the library is not compiled with autoincrement support then
# skip all tests in this file.
#
ifcapable {!autoinc} {
  finish_test
  return
}

sqlite3_db_config_lookaside db 0 0 0

# The database is initially empty.
#
do_test autoinc-1.1 {
  execsql {
    SELECT name FROM sqlite_master WHERE type='table';
  }

  catchsql {
     CREATE TRIGGER trig UPDATE ON t1 FOR EACH STATEMENT BEGIN
        SELECT * FROM sqlite_master;
     END;
  }
} {1 {near "STATEMENT": syntax error}}
execsql {
        CREATE TRIGGER tr1 INSERT ON t1 BEGIN
          INSERT INTO t1 values(1);
         END;
}
do_test trigger1-1.2.0 {
    catchsql {
        CREATE TRIGGER IF NOT EXISTS tr1 DELETE ON t1 BEGIN
            SELECT * FROM sqlite_master;
         END
     }
} {0 {}}
do_test trigger1-1.2.1 {
    catchsql {
        CREATE TRIGGER tr1 DELETE ON t1 BEGIN
            SELECT * FROM sqlite_master;
         END
     }
} {1 {trigger tr1 already exists}}
do_test trigger1-1.2.2 {
    catchsql {
        CREATE TRIGGER "tr1" DELETE ON t1 BEGIN
            SELECT * FROM sqlite_master;
         END
     }
} {1 {trigger "tr1" already exists}}
do_test trigger1-1.2.3 {
    catchsql {
        CREATE TRIGGER [tr1] DELETE ON t1 BEGIN
            SELECT * FROM sqlite_master;
         END
     }
} {1 {trigger [tr1] already exists}}

do_test trigger1-1.3 {
    catchsql {
        BEGIN;
        CREATE TRIGGER tr2 INSERT ON t1 BEGIN
            SELECT * from sqlite_master; END;
        ROLLBACK;
        CREATE TRIGGER tr2 INSERT ON t1 BEGIN
            SELECT * from sqlite_master; END;
    }
} {0 {}}

do_test trigger1-1.4 {
    catchsql {
        DROP TRIGGER IF EXISTS tr1;
        CREATE TRIGGER tr1 DELETE ON t1 BEGIN
            SELECT * FROM sqlite_master;
        END
    }
} {0 {}}

do_test trigger1-1.5 {
    execsql {
        BEGIN;
        DROP TRIGGER tr2;
        ROLLBACK;
        DROP TRIGGER tr2;
    }
} {}

do_test trigger1-1.6.1 {
    catchsql {
        DROP TRIGGER IF EXISTS biggles;
    }
} {0 {}}

do_test trigger1-1.6.2 {
    catchsql {
        DROP TRIGGER biggles;
    }
} {1 {no such trigger: biggles}}

do_test trigger1-1.7 {
    catchsql {
        DROP TABLE t1;
        DROP TRIGGER tr1;
    }
} {1 {no such trigger: tr1}}

ifcapable tempdb {
  execsql {
    CREATE TEMP TABLE temp_table(a);
  }
  do_test trigger1-1.8 {
    execsql {
          CREATE TRIGGER temp_trig UPDATE ON temp_table BEGIN
              SELECT * from sqlite_master;
          END;
          SELECT count(*) FROM sqlite_master WHERE name = 'temp_trig';
    } 
  } {0}
}

do_test trigger1-1.9 {
  catchsql {
    CREATE TRIGGER tr1 AFTER UPDATE ON sqlite_master BEGIN

}
do_test trigger1-6.1 {
  execsql {SELECT type, name FROM sqlite_master}
} [concat $view_v1 {table t2}]
do_test trigger1-6.2 {
  execsql {
    CREATE TRIGGER t2 BEFORE DELETE ON t2 BEGIN
      SELECT RAISE(ABORT,'deletes are not permitted');
    END;
    SELECT type, name FROM sqlite_master;
  }
} [concat $view_v1 {table t2 trigger t2}]
do_test trigger1-6.3 {
  catchsql {DELETE FROM t2}
} {1 {deletes are not permitted}}
do_test trigger1-6.4 {
  execsql {SELECT * FROM t2}
} {3 4 7 8}
do_test trigger1-6.5 {
  db close
  sqlite3 db test.db
  execsql {SELECT type, name FROM sqlite_master}

# heap, use 1000.
#
set nStatement 10000
if {$tcl_platform(platform) == "symbian"} {
  set nStatement 1000
}

set nStatement 5
do_test trigger8-1.1 {
  execsql {
    CREATE TABLE t1(x);
    CREATE TABLE t2(y);
  }
  set sql "CREATE TRIGGER r${nStatement} AFTER INSERT ON t1 BEGIN\n"
  for {set i 0} {$i<$nStatement} {incr i} {