SQLite

  savedDbFlags = db->mDbFlags;  
  if( NEVER(db->mallocFailed) ) goto exit_rename_table;
  assert( pSrc->nSrc==1 );
  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );

  pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
  if( !pTab ) goto exit_rename_table;
  iDb = sqlite3SchemaToIndex2(pParse->db, pTab->pSchema, 0);
  zDb = db->aDb[iDb].zDbSName;
  db->mDbFlags |= DBFLAG_PreferBuiltin;

  /* Get a NULL terminated version of the new table name. */
  zName = sqlite3NameFromToken(db, pName);
  if( !zName ) goto exit_rename_table;

  db = pParse->db;
  if( pParse->nErr || db->mallocFailed ) return;
  pNew = pParse->pNewTable;
  assert( pNew );

  assert( sqlite3BtreeHoldsAllMutexes(db) );
  iDb = sqlite3SchemaToIndex2(db, pNew->pSchema, 0);
  zDb = db->aDb[iDb].zDbSName;
  zTab = &pNew->zName[16];  /* Skip the "sqlite_altertab_" prefix on the name */
  pCol = &pNew->aCol[pNew->nCol-1];
  pDflt = pCol->pDflt;
  pTab = sqlite3FindTable(db, zTab, zDb);
  assert( pTab );

    goto exit_begin_add_column;
  }
  if( SQLITE_OK!=isSystemTable(pParse, pTab->zName) ){
    goto exit_begin_add_column;
  }

  assert( pTab->addColOffset>0 );
  iDb = sqlite3SchemaToIndex2(db, pTab->pSchema, 0);

  /* Put a copy of the Table struct in Parse.pNewTable for the
  ** sqlite3AddColumn() function and friends to modify.  But modify
  ** the name by adding an "sqlite_altertab_" prefix.  By adding this
  ** prefix, we insure that the name will not collide with an existing
  ** table because user table are not allowed to have the "sqlite_"
  ** prefix on their name.

  if( !pTab ) goto exit_rename_column;

  /* Cannot alter a system table */
  if( SQLITE_OK!=isSystemTable(pParse, pTab->zName) ) goto exit_rename_column;
  if( SQLITE_OK!=isRealTable(pParse, pTab) ) goto exit_rename_column;

  /* Which schema holds the table to be altered */  
  iSchema = sqlite3SchemaToIndex2(db, pTab->pSchema, 0);
  assert( iSchema>=0 );
  zDb = db->aDb[iSchema].zDbSName;

#ifndef SQLITE_OMIT_AUTHORIZATION
  /* Invoke the authorization callback. */
  if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
    goto exit_rename_column;

  NameContext sNC;
  int rc = SQLITE_OK;

  memset(&sNC, 0, sizeof(sNC));
  sNC.pParse = pParse;
  assert( pNew->pTabSchema );
  pParse->pTriggerTab = sqlite3FindTable(db, pNew->table, 
      db->aDb[sqlite3SchemaToIndex2(db, pNew->pTabSchema, 0)].zDbSName
  );
  pParse->eTriggerOp = pNew->op;
  /* ALWAYS() because if the table of the trigger does not exist, the
  ** error would have been hit before this point */
  if( ALWAYS(pParse->pTriggerTab) ){
    int iDb = sqlite3SchemaToIndex2(db, pParse->pTriggerTab->pSchema, 0);
    rc = sqlite3ViewGetColumnNames(pParse, iDb, pParse->pTriggerTab);
  }

  /* Resolve symbols in WHEN clause */
  if( rc==SQLITE_OK && pNew->pWhen ){
    rc = sqlite3ResolveExprNames(&sNC, pNew->pWhen);
  }

  for(pStep=pNew->step_list; rc==SQLITE_OK && pStep; pStep=pStep->pNext){
    if( pStep->pSelect ){
      sqlite3SelectPrep(pParse, pStep->pSelect, &sNC);
      if( pParse->nErr ) rc = pParse->rc;
    }
    if( rc==SQLITE_OK && pStep->zTarget ){
      Table *pTarget = sqlite3LocateTable(pParse, 0, pStep->zTarget, zDb);
      if( pTarget==0 ){
        rc = SQLITE_ERROR;
      }else{
        int iDb = sqlite3SchemaToIndex2(db, pTarget->pSchema, 0);
        if( SQLITE_OK==(rc = sqlite3ViewGetColumnNames(pParse, iDb, pTarget)) ){
          SrcList sSrc;
          memset(&sSrc, 0, sizeof(sSrc));
          sSrc.nSrc = 1;
          sSrc.a[0].zName = pStep->zTarget;
          sSrc.a[0].pTab = pTarget;
          sNC.pSrcList = &sSrc;

      }

      else if( sParse.pNewTrigger ){
        if( isLegacy==0 ){
          rc = renameResolveTrigger(&sParse, bTemp ? 0 : zDb);
        }
        if( rc==SQLITE_OK ){
          int i1 = sqlite3SchemaToIndex2(db, sParse.pNewTrigger->pTabSchema, 0);
          int i2 = sqlite3FindDbName(db, zDb);
          if( i1==i2 ) sqlite3_result_int(context, 1);
        }
      }
    }

    if( rc!=SQLITE_OK ){

  int iSrc;             /* Index in pTabList->a[] of table being read */
  int iDb;              /* The index of the database the expression refers to */
  int iCol;             /* Index of column in table */

  assert( pExpr->op==TK_COLUMN || pExpr->op==TK_TRIGGER );
  assert( !IN_RENAME_OBJECT || db->xAuth==0 );
  if( db->xAuth==0 ) return;
  iDb = sqlite3SchemaToIndex(pParse->db, pSchema);
  if( iDb<0 ){
    /* An attempt to read a column out of a subquery or other
    ** temporary table. */
    return;
  }

  if( pExpr->op==TK_TRIGGER ){

** If pSchema is not NULL, then iDb is computed from pSchema and
** db using sqlite3SchemaToIndex().
*/
int sqlite3SchemaMutexHeld(sqlite3 *db, int iDb, Schema *pSchema){
  Btree *p;
  assert( db!=0 );
  if( pSchema && (db->openFlags & SQLITE_OPEN_REUSE_SCHEMA) ) return 1;
  if( pSchema ) iDb = sqlite3SchemaToIndex2(db, pSchema, 0);
  assert( iDb>=0 && iDb<db->nDb );
  if( !sqlite3_mutex_held(db->mutex) ) return 0;
  if( iDb==1 ) return 1;
  p = db->aDb[iDb].pBt;
  assert( p!=0 );
  return p->sharable==0 || p->locked==1;
}

  if( pParse->iFixDb && pParse->iFixDb!=2 ){
    zDb = pParse->db->aDb[pParse->iFixDb-1].zDbSName;
    assert( p->zDatabase==0 || sqlite3StrICmp(p->zDatabase, zDb)==0 );
    if( p->zDatabase==0 ){
      p->zDatabase = sqlite3DbStrDup(pParse->db, zDb);
    }
  }else if( p->pSchema ){
    int iDb = sqlite3SchemaToIndex2(pParse->db, p->pSchema, 0);
    zDb = pParse->db->aDb[iDb].zDbSName;
  }else{
    zDb = p->zDatabase;
  }
  return sqlite3LocateTable(pParse, flags, p->zName, zDb);
}

      sqlite3ErrorMsg(pParse, "PRIMARY KEY missing on table %s", p->zName);
    }else{
      p->tabFlags |= TF_WithoutRowid | TF_NoVisibleRowid;
      convertToWithoutRowidTable(pParse, p);
    }
  }

  iDb = sqlite3SchemaToIndex2(db, p->pSchema, 0);

#ifndef SQLITE_OMIT_CHECK
  /* Resolve names in all CHECK constraint expressions.
  */
  if( p->pCheck ){
    sqlite3ResolveSelfReference(pParse, p, NC_IsCheck, 0, p->pCheck);
  }

    sqlite3ErrorMsg(pParse, "parameters are not allowed in views");
    goto create_view_fail;
  }
  sqlite3StartTable(pParse, pName1, pName2, isTemp, 1, 0, noErr);
  p = pParse->pNewTable;
  if( p==0 || pParse->nErr ) goto create_view_fail;
  sqlite3TwoPartName(pParse, pName1, pName2, &pName);
  iDb = sqlite3SchemaToIndex2(db, p->pSchema, 0);
  sqlite3FixInit(&sFix, pParse, iDb, "view", pName);
  if( sqlite3FixSelect(&sFix, pSelect) ) goto create_view_fail;

  /* Make a copy of the entire SELECT statement that defines the view.
  ** This will force all the Expr.token.z values to be dynamically
  ** allocated rather than point to the input string - which means that
  ** they will persist after the current sqlite3_exec() call returns.

      if( (iDestroyed==0 || (iIdx<iDestroyed)) && iIdx>iLargest ){
        iLargest = iIdx;
      }
    }
    if( iLargest==0 ){
      return;
    }else{
      int iDb = sqlite3SchemaToIndex2(pParse->db, pTab->pSchema, 0);
      assert( iDb>=0 && iDb<pParse->db->nDb );
      destroyRootPage(pParse, iLargest, iDb);
      iDestroyed = iLargest;
    }
  }
}

  pTab = sqlite3LocateTableItem(pParse, isView, &pName->a[0]);
  if( noErr ) db->suppressErr--;

  if( pTab==0 ){
    if( noErr ) sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].zDatabase);
    goto exit_drop_table;
  }
  iDb = sqlite3SchemaToIndex2(db, pTab->pSchema, 0);
  assert( iDb>=0 && iDb<db->nDb );
  sqlite3SchemaWritable(pParse, iDb);

  /* If pTab is a virtual table, call ViewGetColumnNames() to ensure
  ** it is initialized.
  */
  if( IsVirtual(pTab) && sqlite3ViewGetColumnNames(pParse, iDb, pTab) ){

    }
    if( !HasRowid(pTab) ) pPk = sqlite3PrimaryKeyIndex(pTab);
  }else{
    assert( pName==0 );
    assert( pStart==0 );
    pTab = pParse->pNewTable;
    if( !pTab ) goto exit_create_index;
    iDb = sqlite3SchemaToIndex2(db, pTab->pSchema, 0);
  }
  pDb = &db->aDb[iDb];

  assert( pTab!=0 );
  assert( pParse->nErr==0 );
  if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 
       && db->init.busy==0

    goto exit_drop_index;
  }
  if( pIndex->idxType!=SQLITE_IDXTYPE_APPDEF ){
    sqlite3ErrorMsg(pParse, "index associated with UNIQUE "
      "or PRIMARY KEY constraint cannot be dropped", 0);
    goto exit_drop_index;
  }
  iDb = sqlite3SchemaToIndex2(db, pIndex->pSchema, 0);
  sqlite3SchemaWritable(pParse, iDb);
#ifndef SQLITE_OMIT_AUTHORIZATION
  {
    int code = SQLITE_DROP_INDEX;
    Table *pTab = pIndex->pTable;
    const char *zDb = db->aDb[iDb].zDbSName;
    const char *zTab = SCHEMA_TABLE(iDb);

        pParse, pTabList, pWhere, pOrderBy, pLimit, "DELETE"
    );
    pOrderBy = 0;
    pLimit = 0;
  }
#endif

  iDb = sqlite3SchemaToIndex2(db, pTab->pSchema, pTabList->a[0].zDatabase);
  assert( iDb<db->nDb );

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

    assert( p->pEList!=0 );             /* Because of isCandidateForInOpt(p) */
    assert( p->pEList->a[0].pExpr!=0 ); /* Because of isCandidateForInOpt(p) */
    assert( p->pSrc!=0 );               /* Because of isCandidateForInOpt(p) */
    pTab = p->pSrc->a[0].pTab;

    /* Code an OP_Transaction and OP_TableLock for <table>. */
    iDb = sqlite3SchemaToIndex2(db, pTab->pSchema, p->pSrc->a[0].zDatabase);
    sqlite3CodeVerifySchema(pParse, iDb);
    sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);

    assert(v);  /* sqlite3GetVdbe() has always been previously called */
    if( nExpr==1 && pEList->a[0].pExpr->iColumn<0 ){
      /* The "x IN (SELECT rowid FROM table)" case */
      int iAddr = sqlite3VdbeAddOp0(v, OP_Once);

  /* Locate the table into which we will be inserting new information.
  */
  assert( pTabList->nSrc==1 );
  pTab = sqlite3SrcListLookup(pParse, pTabList);
  if( pTab==0 ){
    goto insert_cleanup;
  }
  iDb = sqlite3SchemaToIndex2(db, pTab->pSchema, pTabList->a[0].zDatabase);
  assert( iDb<db->nDb );
  if( sqlite3AuthCheck(pParse, SQLITE_INSERT, pTab->zName, 0,
                       db->aDb[iDb].zDbSName) ){
    goto insert_cleanup;
  }
  withoutRowid = !HasRowid(pTab);

  /* If we get this far, it means that the xfer optimization is at
  ** least a possibility, though it might only work if the destination
  ** table (tab1) is initially empty.
  */
#ifdef SQLITE_TEST
  sqlite3_xferopt_count++;
#endif
  iDbSrc = sqlite3SchemaToIndex2(db, pSrc->pSchema, pItem->zDatabase);
  v = sqlite3GetVdbe(pParse);
  sqlite3CodeVerifySchema(pParse, iDbSrc);
  iSrc = pParse->nTab++;
  iDest = pParse->nTab++;
  regAutoinc = autoIncBegin(pParse, iDbDest, pDest);
  regData = sqlite3GetTempReg(pParse);
  regRowid = sqlite3GetTempReg(pParse);

  */
  case PragTyp_TABLE_INFO: if( zRight ){
    Table *pTab;
    pTab = sqlite3LocateTable(pParse, LOCATE_NOERR, zRight, zDb);
    if( pTab ){
      int i, k;
      int nHidden = 0;
      int iTabDb = sqlite3SchemaToIndex2(db, pTab->pSchema, zDb);
      Column *pCol;
      Index *pPk = sqlite3PrimaryKeyIndex(pTab);
      pParse->nMem = 7;
      sqlite3CodeVerifySchema(pParse, iTabDb);
      sqlite3ViewGetColumnNames(pParse, iTabDb, pTab);
      for(i=0, pCol=pTab->aCol; i<pTab->nCol; i++, pCol++){
        int isHidden = IsHiddenColumn(pCol);

/*
** Convert a schema pointer into the iDb index that indicates
** which database file in db->aDb[] the schema refers to.
**
** If the same database is attached more than once, the first
** attached database is returned.
*/
int sqlite3SchemaToIndex(sqlite3 *db, Schema *pSchema){
  int i = -1000000;











  /* If pSchema is NULL, then return -1000000. This happens when code in 
  ** expr.c is trying to resolve a reference to a transient table (i.e. one
  ** created by a sub-select). In this case the return value of this 
  ** function should never be used.
  **
  ** We return -1000000 instead of the more usual -1 simply because using
  ** -1000000 as the incorrect index into db->aDb[] is much 
  ** more likely to cause a segfault than -1 (of course there are assert()
  ** statements too, but it never hurts to play the odds).
  */
  assert( sqlite3_mutex_held(db->mutex) );
  if( pSchema ){
    for(i=0; 1; i++){
      assert( i<db->nDb );
      if( db->aDb[i].pSchema==pSchema ){
        break;
      }
    }
    assert( i>=0 && i<db->nDb );


  }
  return i;
}

int sqlite3SchemaToIndex2(sqlite3 *db, Schema *pSchema, const char *zDb){
  if( zDb ){
    int i;
    for(i=0; i<db->nDb; i++){
      if( i==1 ) continue;
      if( sqlite3StrICmp(zDb, db->aDb[i].zDbSName)==0 ) return i;
    }
  }
  return sqlite3SchemaToIndex(db, pSchema);
}

/*
** Free all memory allocations in the pParse object
*/
void sqlite3ParserReset(Parse *pParse){
  sqlite3 *db = pParse->db;
  sqlite3DbFree(db, pParse->aLabel);
  sqlite3ExprListDelete(db, pParse->pConstExpr);

              pExpr->iColumn = j;
              hit = 1;
            }
          }
          if( hit || zTab==0 ) continue;
        }
        if( zDb && (pTab->pSchema || pSchema) ){
          int ii = sqlite3SchemaToIndex2(db, pTab->pSchema, pItem->zDatabase);
          if( ii!=iDb ) continue;
        }
        if( zTab ){
          const char *zTabName = pItem->zAlias ? pItem->zAlias : pTab->zName;
          assert( zTabName!=0 );
          if( sqlite3StrICmp(zTabName, zTab)!=0 ){
            continue;

    sqlite3VdbeResolveLabel(v, pSort->labelBkOut);
  }

#ifdef SQLITE_ENABLE_SORTER_REFERENCES
  /* Open any cursors needed for sorter-reference expressions */
  for(i=0; i<pSort->nDefer; i++){
    Table *pTab = pSort->aDefer[i].pTab;
    int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
    sqlite3OpenTable(pParse, pSort->aDefer[i].iCsr, iDb, pTab, OP_OpenRead);
    nRefKey = MAX(nRefKey, pSort->aDefer[i].nKey);
  }
#endif

  iTab = pSort->iECursor;
  if( eDest==SRT_Output || eDest==SRT_Coroutine || eDest==SRT_Mem ){

          zOrigCol = "rowid";
        }else{
          zOrigCol = pTab->aCol[iCol].zName;
          zType = sqlite3ColumnType(&pTab->aCol[iCol],0);
        }
        zOrigTab = pTab->zName;
        if( pNC->pParse && pTab->pSchema ){

          int iDb = sqlite3SchemaToIndex(pNC->pParse->db, pTab->pSchema);
          zOrigDb = pNC->pParse->db->aDb[iDb].zDbSName;
        }
#else
        assert( iCol==XN_ROWID || (iCol>=0 && iCol<pTab->nCol) );
        if( iCol<0 ){
          zType = "INTEGER";
        }else{

      if( !IsVirtual(pTab) && cannotBeFunction(pParse, pFrom) ){
        return WRC_Abort;
      }
#if !defined(SQLITE_OMIT_VIEW) || !defined (SQLITE_OMIT_VIRTUALTABLE)
      if( IsVirtual(pTab) || pTab->pSelect ){
        int iSave = pParse->iFixDb;
        i16 nCol;
        int iDb = sqlite3SchemaToIndex2(db, pTab->pSchema, pFrom->zDatabase);
        pParse->iFixDb = 1 + iDb;
        if( sqlite3ViewGetColumnNames(pParse, iDb, pTab) ){
          pParse->iFixDb = iSave;
          return WRC_Abort;
        }
        assert( pFrom->pSelect==0 );
        pFrom->pSelect = sqlite3SelectDup(db, pTab->pSelect, 0);

          }
          if( db->mallocFailed ) break;
          if( pSub==0 || (pSub->selFlags & SF_NestedFrom)==0 ){
            pSub = 0;
            if( zTName && sqlite3StrICmp(zTName, zTabName)!=0 ){
              continue;
            }
            iDb = sqlite3SchemaToIndex2(db, pTab->pSchema, pFrom->zDatabase);
            zSchemaName = iDb>=0 ? db->aDb[iDb].zDbSName : "*";
          }
          for(j=0; j<pTab->nCol; j++){
            char *zName = pTab->aCol[j].zName;
            char *zColname;  /* The computed column name */
            char *zToFree;   /* Malloced string that needs to be freed */
            Token sColname;  /* Computed column name as a token */

        **
        ** This statement is so common that it is optimized specially. The
        ** OP_Count instruction is executed either on the intkey table that
        ** contains the data for table <tbl> or on one of its indexes. It
        ** is better to execute the op on an index, as indexes are almost
        ** always spread across less pages than their corresponding tables.
        */
        const int iDb = sqlite3SchemaToIndex2(
            pParse->db, pTab->pSchema, pTabList->a[0].zDatabase 
        );
        const int iCsr = pParse->nTab++;     /* Cursor to scan b-tree */
        Index *pIdx;                         /* Iterator variable */
        KeyInfo *pKeyInfo = 0;               /* Keyinfo for scanned index */
        Index *pBest = 0;                    /* Best index found so far */
        int iRoot = pTab->tnum;              /* Root page of scanned b-tree */

void sqlite3RegisterLikeFunctions(sqlite3*, int);
int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);
void sqlite3SchemaClear(void *);
void sqlite3SchemaUnuse(sqlite3*, int);
void sqlite3SchemaReuse(sqlite3*, int);
void sqlite3SchemaWritable(Parse*, int);
Schema *sqlite3SchemaGet(sqlite3 *, Btree *);
int sqlite3SchemaToIndex(sqlite3 *db, Schema *);
int sqlite3SchemaToIndex2(sqlite3 *db, Schema *, const char*);
KeyInfo *sqlite3KeyInfoAlloc(sqlite3*,int,int);
void sqlite3KeyInfoUnref(KeyInfo*);
KeyInfo *sqlite3KeyInfoRef(KeyInfo*);
KeyInfo *sqlite3KeyInfoOfIndex(Parse*, Index*);
KeyInfo *sqlite3KeyInfoFromExprList(Parse*, ExprList*, int, int);

#ifdef SQLITE_DEBUG

    sqlite3ErrorMsg(pParse, "cannot create INSTEAD OF"
        " trigger on table: %S", pTableName, 0);
    goto trigger_cleanup;
  }

#ifndef SQLITE_OMIT_AUTHORIZATION
  if( !IN_RENAME_OBJECT ){
    int iTabDb = sqlite3SchemaToIndex2(db, pTab->pSchema, 0);
    int code = SQLITE_CREATE_TRIGGER;
    const char *zDb = db->aDb[iTabDb].zDbSName;
    const char *zDbTrig = isTemp ? db->aDb[1].zDbSName : zDb;
    if( iTabDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER;
    if( sqlite3AuthCheck(pParse, code, zName, pTab->zName, zDbTrig) ){
      goto trigger_cleanup;
    }

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

  pParse->pNewTrigger = 0;
  if( NEVER(pParse->nErr) || !pTrig ) goto triggerfinish_cleanup;
  zName = pTrig->zName;
  iDb = sqlite3SchemaToIndex2(pParse->db, pTrig->pSchema, 0);
  pTrig->step_list = pStepList;
  while( pStepList ){
    pStepList->pTrig = pTrig;
    pStepList = pStepList->pNext;
  }
  sqlite3TokenInit(&nameToken, pTrig->zName);
  sqlite3FixInit(&sFix, pParse, iDb, "trigger", &nameToken);

*/
void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger){
  Table   *pTable;
  Vdbe *v;
  sqlite3 *db = pParse->db;
  int iDb;

  iDb = sqlite3SchemaToIndex2(pParse->db, pTrigger->pSchema, 0);
  assert( iDb>=0 && iDb<db->nDb );
  sqlite3SchemaWritable(pParse, iDb);
  pTable = tableOfTrigger(pTrigger);
  assert( pTable );
  assert( pTable->pSchema==pTrigger->pSchema || iDb==1 );
#ifndef SQLITE_OMIT_AUTHORIZATION
  {

  }
  assert( pTabList->nSrc==1 );

  /* Locate the table which we want to update. 
  */
  pTab = sqlite3SrcListLookup(pParse, pTabList);
  if( pTab==0 ) goto update_cleanup;
  iDb = sqlite3SchemaToIndex2(db, pTab->pSchema, pTabList->a[0].zDatabase);

  /* Figure out if we have any triggers and if the table being
  ** updated is a view.
  */
#ifndef SQLITE_OMIT_TRIGGER
  pTrigger = sqlite3TriggersExist(pParse, pTab, TK_UPDATE, pChanges, &tmask);
  isView = pTab->pSelect!=0;

        sParse.zErrMsg = 0;
      }
      rc = SQLITE_ERROR;
      sqlite3BtreeLeaveAll(db);
      goto blob_open_out;
    }
    pBlob->pTab = pTab;
    pBlob->zDb = db->aDb[sqlite3SchemaToIndex2(db,pTab->pSchema,zDb)].zDbSName;

    /* Now search pTab for the exact column. */
    for(iCol=0; iCol<pTab->nCol; iCol++) {
      if( sqlite3StrICmp(pTab->aCol[iCol].zName, zColumn)==0 ){
        break;
      }
    }

        /* blobSeekToRow() will initialize r[1] to the desired rowid */
        {OP_NotExists,      0, 5, 1},  /* 2: Seek the cursor to rowid=r[1] */
        {OP_Column,         0, 0, 1},  /* 3  */
        {OP_ResultRow,      1, 0, 0},  /* 4  */
        {OP_Halt,           0, 0, 0},  /* 5  */
      };
      Vdbe *v = (Vdbe *)pBlob->pStmt;
      int iDb = sqlite3SchemaToIndex2(db, pTab->pSchema, zDb);
      VdbeOp *aOp;

      sqlite3VdbeAddOp4Int(v, OP_Transaction, iDb, wrFlag, 
                           pTab->pSchema->schema_cookie,
                           pTab->pSchema->iGeneration);
      sqlite3VdbeChangeP5(v, 1);
      assert( sqlite3VdbeCurrentAddr(v)==2 || db->mallocFailed );

#ifndef SQLITE_OMIT_AUTHORIZATION
  /* Creating a virtual table invokes the authorization callback twice.
  ** The first invocation, to obtain permission to INSERT a row into the
  ** sqlite_master table, has already been made by sqlite3StartTable().
  ** The second call, to obtain permission to create the table, is made now.
  */
  if( pTable->azModuleArg ){
    int iDb = sqlite3SchemaToIndex(db, pTable->pSchema);
    assert( iDb>=0 ); /* The database the table is being created in */
    sqlite3AuthCheck(pParse, SQLITE_CREATE_VTABLE, pTable->zName, 
            pTable->azModuleArg[0], pParse->db->aDb[iDb].zDbSName);
  }
#endif
}

    ** SQLITE_MASTER table.  We just need to update that slot with all
    ** the information we've collected.  
    **
    ** The VM register number pParse->regRowid holds the rowid of an
    ** entry in the sqlite_master table tht was created for this vtab
    ** by sqlite3StartTable().
    */
    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
    sqlite3NestedParse(pParse,
      "UPDATE %Q.%s "
         "SET type='table', name=%Q, tbl_name=%Q, rootpage=0, sql=%Q "
       "WHERE rowid=#%d",
      db->aDb[iDb].zDbSName, MASTER_NAME,
      pTab->zName,
      pTab->zName,

*/
static int vtabBestIndex(
  Parse *pParse, 
  struct SrcList_item *pSrc, 
  sqlite3_index_info *p
){
  Table *pTab = pSrc->pTab;
  int iDb = sqlite3SchemaToIndex2(pParse->db, pTab->pSchema, pSrc->zDatabase);
  sqlite3_vtab *pVtab = sqlite3GetVTable(pParse->db, iDb, pTab)->pVtab;
  int rc;

  TRACE_IDX_INPUTS(p);
  rc = pVtab->pModule->xBestIndex(pVtab, p);
  TRACE_IDX_OUTPUTS(p);

  for(ii=0, pLevel=pWInfo->a; ii<nTabList; ii++, pLevel++){
    Table *pTab;     /* Table to open */
    int iDb;         /* Index of database containing table/index */
    struct SrcList_item *pTabItem;

    pTabItem = &pTabList->a[pLevel->iFrom];
    pTab = pTabItem->pTab;
    iDb = sqlite3SchemaToIndex2(db, pTab->pSchema, pTabItem->zDatabase);
    pLoop = pLevel->pWLoop;
    if( (pTab->tabFlags & TF_Ephemeral)!=0 || pTab->pSelect ){
      /* Do nothing */
    }else
#ifndef SQLITE_OMIT_VIRTUALTABLE
    if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){
      const char *pVTab = (const char *)sqlite3GetVTable(db, iDb, pTab);