int savedDbFlags;         /* Saved value of db->flags */

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

  pTab = sqlite3LocateTable(pParse, 0, pSrc->a[0].zName, pSrc->a[0].zDatabase);
  if( !pTab ) goto exit_rename_table;
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  zDb = db->aDb[iDb].zName;
  db->flags |= SQLITE_PreferBuiltin;

  /* Get a NULL terminated version of the new table name. */
  zName = sqlite3NameFromToken(db, pName);
................................................................................
  int nAlloc;
  sqlite3 *db = pParse->db;

  /* Look up the table being altered. */
  assert( pParse->pNewTable==0 );
  assert( sqlite3BtreeHoldsAllMutexes(db) );
  if( db->mallocFailed ) goto exit_begin_add_column;
  pTab = sqlite3LocateTable(pParse, 0, pSrc->a[0].zName, pSrc->a[0].zDatabase);
  if( !pTab ) goto exit_begin_add_column;

#ifndef SQLITE_OMIT_VIRTUALTABLE
  if( IsVirtual(pTab) ){
    sqlite3ErrorMsg(pParse, "virtual tables may not be altered");
    goto exit_begin_add_column;
  }

  int savedDbFlags;         /* Saved value of db->flags */

  savedDbFlags = db->flags;  
  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 = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  zDb = db->aDb[iDb].zName;
  db->flags |= SQLITE_PreferBuiltin;

  /* Get a NULL terminated version of the new table name. */
  zName = sqlite3NameFromToken(db, pName);
................................................................................
  int nAlloc;
  sqlite3 *db = pParse->db;

  /* Look up the table being altered. */
  assert( pParse->pNewTable==0 );
  assert( sqlite3BtreeHoldsAllMutexes(db) );
  if( db->mallocFailed ) goto exit_begin_add_column;
  pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
  if( !pTab ) goto exit_begin_add_column;

#ifndef SQLITE_OMIT_VIRTUALTABLE
  if( IsVirtual(pTab) ){
    sqlite3ErrorMsg(pParse, "virtual tables may not be altered");
    goto exit_begin_add_column;
  }

  sqlite3 *db;

  if( NEVER(iDb<0) || iDb==1 ) return 0;
  db = pParse->db;
  assert( db->nDb>iDb );
  pFix->pParse = pParse;
  pFix->zDb = db->aDb[iDb].zName;

  pFix->zType = zType;
  pFix->pName = pName;
  return 1;
}

/*
** The following set of routines walk through the parse tree and assign
................................................................................
  int i;
  const char *zDb;
  struct SrcList_item *pItem;

  if( NEVER(pList==0) ) return 0;
  zDb = pFix->zDb;
  for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
    if( pItem->zDatabase==0 ){
      pItem->zDatabase = sqlite3DbStrDup(pFix->pParse->db, zDb);
    }else if( sqlite3StrICmp(pItem->zDatabase,zDb)!=0 ){
      sqlite3ErrorMsg(pFix->pParse,
         "%s %T cannot reference objects in database %s",
         pFix->zType, pFix->pName, pItem->zDatabase);
      return 1;
    }



#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER)
    if( sqlite3FixSelect(pFix, pItem->pSelect) ) return 1;
    if( sqlite3FixExpr(pFix, pItem->pOn) ) return 1;
#endif
  }
  return 0;
}

  sqlite3 *db;

  if( NEVER(iDb<0) || iDb==1 ) return 0;
  db = pParse->db;
  assert( db->nDb>iDb );
  pFix->pParse = pParse;
  pFix->zDb = db->aDb[iDb].zName;
  pFix->pSchema = db->aDb[iDb].pSchema;
  pFix->zType = zType;
  pFix->pName = pName;
  return 1;
}

/*
** The following set of routines walk through the parse tree and assign
................................................................................
  int i;
  const char *zDb;
  struct SrcList_item *pItem;

  if( NEVER(pList==0) ) return 0;
  zDb = pFix->zDb;
  for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){


    if( pItem->zDatabase && sqlite3StrICmp(pItem->zDatabase, zDb) ){
      sqlite3ErrorMsg(pFix->pParse,
         "%s %T cannot reference objects in database %s",
         pFix->zType, pFix->pName, pItem->zDatabase);
      return 1;
    }
    sqlite3_free(pItem->zDatabase);
    pItem->zDatabase = 0;
    pItem->pSchema = pFix->pSchema;
#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER)
    if( sqlite3FixSelect(pFix, pItem->pSelect) ) return 1;
    if( sqlite3FixExpr(pFix, pItem->pOn) ) return 1;
#endif
  }
  return 0;
}

    }else{
      sqlite3ErrorMsg(pParse, "%s: %s", zMsg, zName);
    }
    pParse->checkSchema = 1;
  }
  return p;
}


























/*
** Locate the in-memory structure that describes 
** a particular index given the name of that index
** and the name of the database that contains the index.
** Return NULL if not found.
**
................................................................................

  if( db->mallocFailed ){
    goto exit_drop_table;
  }
  assert( pParse->nErr==0 );
  assert( pName->nSrc==1 );
  if( noErr ) db->suppressErr++;
  pTab = sqlite3LocateTable(pParse, isView, 
                            pName->a[0].zName, pName->a[0].zDatabase);
  if( noErr ) db->suppressErr--;

  if( pTab==0 ){
    if( noErr ) sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].zDatabase);
    goto exit_drop_table;
  }
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
................................................................................
    if( sqlite3FixInit(&sFix, pParse, iDb, "index", pName) &&
        sqlite3FixSrcList(&sFix, pTblName)
    ){
      /* Because the parser constructs pTblName from a single identifier,
      ** sqlite3FixSrcList can never fail. */
      assert(0);
    }
    pTab = sqlite3LocateTable(pParse, 0, pTblName->a[0].zName, 
        pTblName->a[0].zDatabase);
    if( !pTab || db->mallocFailed ) goto exit_create_index;
    assert( db->aDb[iDb].pSchema==pTab->pSchema );
  }else{
    assert( pName==0 );
    assert( pStart==0 );
    pTab = pParse->pNewTable;
    if( !pTab ) goto exit_create_index;

    }else{
      sqlite3ErrorMsg(pParse, "%s: %s", zMsg, zName);
    }
    pParse->checkSchema = 1;
  }
  return p;
}

/*
** Locate the table identified by *p.
**
** This is a wrapper around sqlite3LocateTable(). The difference between
** sqlite3LocateTable() and this function is that this function restricts
** the search to schema (p->pSchema) if it is not NULL. p->pSchema may be
** non-NULL if it is part of a view or trigger program definition. See
** sqlite3FixSrcList() for details.
*/
Table *sqlite3LocateTableItem(
  Parse *pParse, 
  int isView, 
  struct SrcList_item *p
){
  const char *zDb;
  assert( p->pSchema==0 || p->zDatabase==0 );
  if( p->pSchema ){
    int iDb = sqlite3SchemaToIndex(pParse->db, p->pSchema);
    zDb = pParse->db->aDb[iDb].zName;
  }else{
    zDb = p->zDatabase;
  }
  return sqlite3LocateTable(pParse, isView, p->zName, zDb);
}

/*
** Locate the in-memory structure that describes 
** a particular index given the name of that index
** and the name of the database that contains the index.
** Return NULL if not found.
**
................................................................................

  if( db->mallocFailed ){
    goto exit_drop_table;
  }
  assert( pParse->nErr==0 );
  assert( pName->nSrc==1 );
  if( noErr ) db->suppressErr++;
  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 = sqlite3SchemaToIndex(db, pTab->pSchema);
................................................................................
    if( sqlite3FixInit(&sFix, pParse, iDb, "index", pName) &&
        sqlite3FixSrcList(&sFix, pTblName)
    ){
      /* Because the parser constructs pTblName from a single identifier,
      ** sqlite3FixSrcList can never fail. */
      assert(0);
    }
    pTab = sqlite3LocateTableItem(pParse, 0, &pTblName->a[0]);

    if( !pTab || db->mallocFailed ) goto exit_create_index;
    assert( db->aDb[iDb].pSchema==pTab->pSchema );
  }else{
    assert( pName==0 );
    assert( pStart==0 );
    pTab = pParse->pNewTable;
    if( !pTab ) goto exit_create_index;

**    pSrc->a[0].pIndex     Pointer to the INDEXED BY index, if there is one
**
*/
Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc){
  struct SrcList_item *pItem = pSrc->a;
  Table *pTab;
  assert( pItem && pSrc->nSrc==1 );
  pTab = sqlite3LocateTable(pParse, 0, pItem->zName, pItem->zDatabase);
  sqlite3DeleteTable(pParse->db, pItem->pTab);
  pItem->pTab = pTab;
  if( pTab ){
    pTab->nRef++;
  }
  if( sqlite3IndexedByLookup(pParse, pItem) ){
    pTab = 0;

**    pSrc->a[0].pIndex     Pointer to the INDEXED BY index, if there is one
**
*/
Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc){
  struct SrcList_item *pItem = pSrc->a;
  Table *pTab;
  assert( pItem && pSrc->nSrc==1 );
  pTab = sqlite3LocateTableItem(pParse, 0, pItem);
  sqlite3DeleteTable(pParse->db, pItem->pTab);
  pItem->pTab = pTab;
  if( pTab ){
    pTab->nRef++;
  }
  if( sqlite3IndexedByLookup(pParse, pItem) ){
    pTab = 0;

  pNew = sqlite3DbMallocRaw(db, nByte );
  if( pNew==0 ) return 0;
  pNew->nSrc = pNew->nAlloc = p->nSrc;
  for(i=0; i<p->nSrc; i++){
    struct SrcList_item *pNewItem = &pNew->a[i];
    struct SrcList_item *pOldItem = &p->a[i];
    Table *pTab;

    pNewItem->zDatabase = sqlite3DbStrDup(db, pOldItem->zDatabase);
    pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
    pNewItem->zAlias = sqlite3DbStrDup(db, pOldItem->zAlias);
    pNewItem->jointype = pOldItem->jointype;
    pNewItem->iCursor = pOldItem->iCursor;
    pNewItem->addrFillSub = pOldItem->addrFillSub;
    pNewItem->regReturn = pOldItem->regReturn;

  pNew = sqlite3DbMallocRaw(db, nByte );
  if( pNew==0 ) return 0;
  pNew->nSrc = pNew->nAlloc = p->nSrc;
  for(i=0; i<p->nSrc; i++){
    struct SrcList_item *pNewItem = &pNew->a[i];
    struct SrcList_item *pOldItem = &p->a[i];
    Table *pTab;
    pNewItem->pSchema = pOldItem->pSchema;
    pNewItem->zDatabase = sqlite3DbStrDup(db, pOldItem->zDatabase);
    pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
    pNewItem->zAlias = sqlite3DbStrDup(db, pOldItem->zAlias);
    pNewItem->jointype = pOldItem->jointype;
    pNewItem->iCursor = pOldItem->iCursor;
    pNewItem->addrFillSub = pOldItem->addrFillSub;
    pNewItem->regReturn = pOldItem->regReturn;

#ifndef SQLITE_OMIT_CHECK
  if( pTab->pCheck && (db->flags & SQLITE_IgnoreChecks)==0 ){
    ExprList *pCheck = pTab->pCheck;
    pParse->ckBase = regData;
    onError = overrideError!=OE_Default ? overrideError : OE_Abort;
    for(i=0; i<pCheck->nExpr; i++){
      int allOk = sqlite3VdbeMakeLabel(v);


      sqlite3ExprIfTrue(pParse, pCheck->a[i].pExpr, allOk, SQLITE_JUMPIFNULL);
      if( onError==OE_Ignore ){
        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
      }else{
        char *zConsName = pCheck->a[i].zName;
        if( onError==OE_Replace ) onError = OE_Abort; /* IMP: R-15569-63625 */
        if( zConsName ){
          zConsName = sqlite3MPrintf(db, "constraint %s failed", zConsName);
        }else{
          zConsName = 0;
        }
        sqlite3HaltConstraint(pParse, onError, zConsName, P4_DYNAMIC);
      }
      sqlite3VdbeResolveLabel(v, allOk);

    }
  }
#endif /* !defined(SQLITE_OMIT_CHECK) */

  /* If we have an INTEGER PRIMARY KEY, make sure the primary key
  ** of the new record does not previously exist.  Except, if this
  ** is an UPDATE and the primary key is not changing, that is OK.
................................................................................
  }

  /* At this point we have established that the statement is of the
  ** correct syntactic form to participate in this optimization.  Now
  ** we have to check the semantics.
  */
  pItem = pSelect->pSrc->a;
  pSrc = sqlite3LocateTable(pParse, 0, pItem->zName, pItem->zDatabase);
  if( pSrc==0 ){
    return 0;   /* FROM clause does not contain a real table */
  }
  if( pSrc==pDest ){
    return 0;   /* tab1 and tab2 may not be the same table */
  }
#ifndef SQLITE_OMIT_VIRTUALTABLE

#ifndef SQLITE_OMIT_CHECK
  if( pTab->pCheck && (db->flags & SQLITE_IgnoreChecks)==0 ){
    ExprList *pCheck = pTab->pCheck;
    pParse->ckBase = regData;
    onError = overrideError!=OE_Default ? overrideError : OE_Abort;
    for(i=0; i<pCheck->nExpr; i++){
      int allOk = sqlite3VdbeMakeLabel(v);
      Expr *pDup = sqlite3ExprDup(db, pCheck->a[i].pExpr, 0);
      if( pDup==0 ) break;
      sqlite3ExprIfTrue(pParse, pDup, allOk, SQLITE_JUMPIFNULL);
      if( onError==OE_Ignore ){
        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
      }else{
        char *zConsName = pCheck->a[i].zName;
        if( onError==OE_Replace ) onError = OE_Abort; /* IMP: R-15569-63625 */
        if( zConsName ){
          zConsName = sqlite3MPrintf(db, "constraint %s failed", zConsName);
        }else{
          zConsName = 0;
        }
        sqlite3HaltConstraint(pParse, onError, zConsName, P4_DYNAMIC);
      }
      sqlite3VdbeResolveLabel(v, allOk);
      sqlite3ExprDelete(db, pDup);
    }
  }
#endif /* !defined(SQLITE_OMIT_CHECK) */

  /* If we have an INTEGER PRIMARY KEY, make sure the primary key
  ** of the new record does not previously exist.  Except, if this
  ** is an UPDATE and the primary key is not changing, that is OK.
................................................................................
  }

  /* At this point we have established that the statement is of the
  ** correct syntactic form to participate in this optimization.  Now
  ** we have to check the semantics.
  */
  pItem = pSelect->pSrc->a;
  pSrc = sqlite3LocateTableItem(pParse, 0, pItem);
  if( pSrc==0 ){
    return 0;   /* FROM clause does not contain a real table */
  }
  if( pSrc==pDest ){
    return 0;   /* tab1 and tab2 may not be the same table */
  }
#ifndef SQLITE_OMIT_VIRTUALTABLE

      pTab->iPKey = -1;
      pTab->nRowEst = 1000000;
      pTab->tabFlags |= TF_Ephemeral;
#endif
    }else{
      /* An ordinary table or view name in the FROM clause */
      assert( pFrom->pTab==0 );
      pFrom->pTab = pTab = 
        sqlite3LocateTable(pParse,0,pFrom->zName,pFrom->zDatabase);
      if( pTab==0 ) return WRC_Abort;
      pTab->nRef++;
#if !defined(SQLITE_OMIT_VIEW) || !defined (SQLITE_OMIT_VIRTUALTABLE)
      if( pTab->pSelect || IsVirtual(pTab) ){
        /* We reach here if the named table is a really a view */
        if( sqlite3ViewGetColumnNames(pParse, pTab) ) return WRC_Abort;
        assert( pFrom->pSelect==0 );

      pTab->iPKey = -1;
      pTab->nRowEst = 1000000;
      pTab->tabFlags |= TF_Ephemeral;
#endif
    }else{
      /* An ordinary table or view name in the FROM clause */
      assert( pFrom->pTab==0 );
      pFrom->pTab = pTab = sqlite3LocateTableItem(pParse, 0, pFrom);

      if( pTab==0 ) return WRC_Abort;
      pTab->nRef++;
#if !defined(SQLITE_OMIT_VIEW) || !defined (SQLITE_OMIT_VIRTUALTABLE)
      if( pTab->pSelect || IsVirtual(pTab) ){
        /* We reach here if the named table is a really a view */
        if( sqlite3ViewGetColumnNames(pParse, pTab) ) return WRC_Abort;
        assert( pFrom->pSelect==0 );

** In the colUsed field, the high-order bit (bit 63) is set if the table
** contains more than 63 columns and the 64-th or later column is used.
*/
struct SrcList {
  i16 nSrc;        /* Number of tables or subqueries in the FROM clause */
  i16 nAlloc;      /* Number of entries allocated in a[] below */
  struct SrcList_item {

    char *zDatabase;  /* Name of database holding this table */
    char *zName;      /* Name of the table */
    char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
    Table *pTab;      /* An SQL table corresponding to zName */
    Select *pSelect;  /* A SELECT statement used in place of a table name */
    int addrFillSub;  /* Address of subroutine to manifest a subquery */
    int regReturn;    /* Register holding return address of addrFillSub */
................................................................................
** The following structure contains information used by the sqliteFix...
** routines as they walk the parse tree to make database references
** explicit.  
*/
typedef struct DbFixer DbFixer;
struct DbFixer {
  Parse *pParse;      /* The parsing context.  Error messages written here */

  const char *zDb;    /* Make sure all objects are contained in this database */
  const char *zType;  /* Type of the container - used for error messages */
  const Token *pName; /* Name of the container - used for error messages */
};

/*
** An objected used to accumulate the text of a string where we
................................................................................
int sqlite3ExprCodeAndCache(Parse*, Expr*, int);
void sqlite3ExprCodeConstants(Parse*, Expr*);
int sqlite3ExprCodeExprList(Parse*, ExprList*, int, int);
void sqlite3ExprIfTrue(Parse*, Expr*, int, int);
void sqlite3ExprIfFalse(Parse*, Expr*, int, int);
Table *sqlite3FindTable(sqlite3*,const char*, const char*);
Table *sqlite3LocateTable(Parse*,int isView,const char*, const char*);

Index *sqlite3FindIndex(sqlite3*,const char*, const char*);
void sqlite3UnlinkAndDeleteTable(sqlite3*,int,const char*);
void sqlite3UnlinkAndDeleteIndex(sqlite3*,int,const char*);
void sqlite3Vacuum(Parse*);
int sqlite3RunVacuum(char**, sqlite3*);
char *sqlite3NameFromToken(sqlite3*, Token*);
int sqlite3ExprCompare(Expr*, Expr*);

** In the colUsed field, the high-order bit (bit 63) is set if the table
** contains more than 63 columns and the 64-th or later column is used.
*/
struct SrcList {
  i16 nSrc;        /* Number of tables or subqueries in the FROM clause */
  i16 nAlloc;      /* Number of entries allocated in a[] below */
  struct SrcList_item {
    Schema *pSchema;  /* Schema to which this item is fixed */
    char *zDatabase;  /* Name of database holding this table */
    char *zName;      /* Name of the table */
    char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
    Table *pTab;      /* An SQL table corresponding to zName */
    Select *pSelect;  /* A SELECT statement used in place of a table name */
    int addrFillSub;  /* Address of subroutine to manifest a subquery */
    int regReturn;    /* Register holding return address of addrFillSub */
................................................................................
** The following structure contains information used by the sqliteFix...
** routines as they walk the parse tree to make database references
** explicit.  
*/
typedef struct DbFixer DbFixer;
struct DbFixer {
  Parse *pParse;      /* The parsing context.  Error messages written here */
  Schema *pSchema;    /* Fix items to this schema */
  const char *zDb;    /* Make sure all objects are contained in this database */
  const char *zType;  /* Type of the container - used for error messages */
  const Token *pName; /* Name of the container - used for error messages */
};

/*
** An objected used to accumulate the text of a string where we
................................................................................
int sqlite3ExprCodeAndCache(Parse*, Expr*, int);
void sqlite3ExprCodeConstants(Parse*, Expr*);
int sqlite3ExprCodeExprList(Parse*, ExprList*, int, int);
void sqlite3ExprIfTrue(Parse*, Expr*, int, int);
void sqlite3ExprIfFalse(Parse*, Expr*, int, int);
Table *sqlite3FindTable(sqlite3*,const char*, const char*);
Table *sqlite3LocateTable(Parse*,int isView,const char*, const char*);
Table *sqlite3LocateTableItem(Parse*,int isView,struct SrcList_item *);
Index *sqlite3FindIndex(sqlite3*,const char*, const char*);
void sqlite3UnlinkAndDeleteTable(sqlite3*,int,const char*);
void sqlite3UnlinkAndDeleteIndex(sqlite3*,int,const char*);
void sqlite3Vacuum(Parse*);
int sqlite3RunVacuum(char**, sqlite3*);
char *sqlite3NameFromToken(sqlite3*, Token*);
int sqlite3ExprCompare(Expr*, Expr*);

** in the list are moved to the sqlite3.pDisconnect list of the associated 
** database connection.
*/
void sqlite3VtabClear(sqlite3 *db, Table *p){
  if( !db || db->pnBytesFreed==0 ) vtabDisconnectAll(0, p);
  if( p->azModuleArg ){
    int i;

    for(i=0; i<p->nModuleArg; i++){
      sqlite3DbFree(db, p->azModuleArg[i]);
    }
    sqlite3DbFree(db, p->azModuleArg);
  }
}

................................................................................
  db = pParse->db;
  iDb = sqlite3SchemaToIndex(db, pTable->pSchema);
  assert( iDb>=0 );

  pTable->tabFlags |= TF_Virtual;
  pTable->nModuleArg = 0;
  addModuleArgument(db, pTable, sqlite3NameFromToken(db, pModuleName));
  addModuleArgument(db, pTable, sqlite3DbStrDup(db, db->aDb[iDb].zName));
  addModuleArgument(db, pTable, sqlite3DbStrDup(db, pTable->zName));
  pParse->sNameToken.n = (int)(&pModuleName->z[pModuleName->n] - pName1->z);

#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().
................................................................................
  VtabCtx sCtx, *pPriorCtx;
  VTable *pVTable;
  int rc;
  const char *const*azArg = (const char *const*)pTab->azModuleArg;
  int nArg = pTab->nModuleArg;
  char *zErr = 0;
  char *zModuleName = sqlite3MPrintf(db, "%s", pTab->zName);


  if( !zModuleName ){
    return SQLITE_NOMEM;
  }

  pVTable = sqlite3DbMallocZero(db, sizeof(VTable));
  if( !pVTable ){
    sqlite3DbFree(db, zModuleName);
    return SQLITE_NOMEM;
  }
  pVTable->db = db;
  pVTable->pMod = pMod;





  /* Invoke the virtual table constructor */
  assert( &db->pVtabCtx );
  assert( xConstruct );
  sCtx.pTab = pTab;
  sCtx.pVTable = pVTable;
  pPriorCtx = db->pVtabCtx;
  db->pVtabCtx = &sCtx;
  rc = xConstruct(db, pMod->pAux, nArg, azArg, &pVTable->pVtab, &zErr);
  db->pVtabCtx = pPriorCtx;
  if( rc==SQLITE_NOMEM ) db->mallocFailed = 1;


  if( SQLITE_OK!=rc ){
    if( zErr==0 ){
      *pzErr = sqlite3MPrintf(db, "vtable constructor failed: %s", zModuleName);
    }else {
      *pzErr = sqlite3MPrintf(db, "%s", zErr);
      sqlite3_free(zErr);

** in the list are moved to the sqlite3.pDisconnect list of the associated 
** database connection.
*/
void sqlite3VtabClear(sqlite3 *db, Table *p){
  if( !db || db->pnBytesFreed==0 ) vtabDisconnectAll(0, p);
  if( p->azModuleArg ){
    int i;
    assert( p->nModuleArg<2 || p->azModuleArg[1]==0 );
    for(i=0; i<p->nModuleArg; i++){
      sqlite3DbFree(db, p->azModuleArg[i]);
    }
    sqlite3DbFree(db, p->azModuleArg);
  }
}

................................................................................
  db = pParse->db;
  iDb = sqlite3SchemaToIndex(db, pTable->pSchema);
  assert( iDb>=0 );

  pTable->tabFlags |= TF_Virtual;
  pTable->nModuleArg = 0;
  addModuleArgument(db, pTable, sqlite3NameFromToken(db, pModuleName));
  addModuleArgument(db, pTable, 0);
  addModuleArgument(db, pTable, sqlite3DbStrDup(db, pTable->zName));
  pParse->sNameToken.n = (int)(&pModuleName->z[pModuleName->n] - pName1->z);

#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().
................................................................................
  VtabCtx sCtx, *pPriorCtx;
  VTable *pVTable;
  int rc;
  const char *const*azArg = (const char *const*)pTab->azModuleArg;
  int nArg = pTab->nModuleArg;
  char *zErr = 0;
  char *zModuleName = sqlite3MPrintf(db, "%s", pTab->zName);
  int iDb;

  if( !zModuleName ){
    return SQLITE_NOMEM;
  }

  pVTable = sqlite3DbMallocZero(db, sizeof(VTable));
  if( !pVTable ){
    sqlite3DbFree(db, zModuleName);
    return SQLITE_NOMEM;
  }
  pVTable->db = db;
  pVTable->pMod = pMod;

  assert( pTab->azModuleArg[1]==0 );
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  pTab->azModuleArg[1] = db->aDb[iDb].zName;

  /* Invoke the virtual table constructor */
  assert( &db->pVtabCtx );
  assert( xConstruct );
  sCtx.pTab = pTab;
  sCtx.pVTable = pVTable;
  pPriorCtx = db->pVtabCtx;
  db->pVtabCtx = &sCtx;
  rc = xConstruct(db, pMod->pAux, nArg, azArg, &pVTable->pVtab, &zErr);
  db->pVtabCtx = pPriorCtx;
  if( rc==SQLITE_NOMEM ) db->mallocFailed = 1;
  pTab->azModuleArg[1] = 0;

  if( SQLITE_OK!=rc ){
    if( zErr==0 ){
      *pzErr = sqlite3MPrintf(db, "vtable constructor failed: %s", zModuleName);
    }else {
      *pzErr = sqlite3MPrintf(db, "%s", zErr);
      sqlite3_free(zErr);

# 2012 October 5
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
#
# The tests in this file are intended to show if two connections attach
# to the same shared cache using different database names, views and
# virtual tables may still be accessed.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix shared9

ifcapable !view||!trigger {
  finish_test
  return
}

db close
set enable_shared_cache [sqlite3_enable_shared_cache 1]

sqlite3 db1 test.db
sqlite3 db2 test.db
forcedelete test.db2

do_test 1.1 {
  db1 eval {
    ATTACH 'test.db2' AS 'fred';
    CREATE TABLE fred.t1(a, b, c);
    CREATE VIEW fred.v1 AS SELECT * FROM t1;

    CREATE TABLE fred.t2(a, b);
    CREATE TABLE fred.t3(a, b);
    CREATE TRIGGER fred.trig AFTER INSERT ON t2 BEGIN
      DELETE FROM t3;
      INSERT INTO t3 SELECT * FROM t2;
    END;
    INSERT INTO t2 VALUES(1, 2);
    SELECT * FROM t3;
  }
} {1 2}

do_test 1.2 { db2 eval "ATTACH 'test.db2' AS 'jones'" } {}
do_test 1.3 { db2 eval "SELECT * FROM v1"             } {}
do_test 1.4 { db2 eval "INSERT INTO t2 VALUES(3, 4)"  } {}

ifcapable fts3 {
  do_test 1.5 {
    db1 eval {
      CREATE VIRTUAL TABLE fred.t4 USING fts4;
      INSERT INTO t4 VALUES('hello world');
    }
  } {}

  do_test 1.6 {
    db2 eval {
      INSERT INTO t4 VALUES('shared cache');
      SELECT * FROM t4 WHERE t4 MATCH 'hello';
    }
  } {{hello world}}

  do_test 1.7 {
    db1 eval {
      SELECT * FROM t4 WHERE t4 MATCH 'c*';
    }
  } {{shared cache}}
}

db1 close
db2 close

#-------------------------------------------------------------------------
# The following tests attempt to find a similar problem with collation 
# sequence names - pointers to database handle specific allocations leaking 
# into schema objects and being used after the original handle has been
# closed.
#
forcedelete test.db test.db2
sqlite3 db1 test.db
sqlite3 db2 test.db
foreach x {collate1 collate2 collate3} {
  proc $x {a b} { string compare $a $b }
  db1 collate $x $x
  db2 collate $x $x
}
do_test 2.1 {
  db1 eval {
    CREATE TABLE t1(a, b, c COLLATE collate1);
    CREATE INDEX i1 ON t1(a COLLATE collate2, c, b);
  }
} {}
do_test 2.2 {
  db1 close
  db2 eval "INSERT INTO t1 VALUES('abc', 'def', 'ghi')"
} {}
db2 close

#-------------------------------------------------------------------------
# At one point, the following would cause a collation sequence belonging
# to connection [db1] to be invoked by a call to [db2 eval]. Which is a
# problem if [db1] has already been closed.
#
forcedelete test.db test.db2
sqlite3 db1 test.db
sqlite3 db2 test.db

proc mycollate_db1 {a b} {set ::invoked_mycollate_db1 1 ; string compare $a $b}
proc mycollate_db2 {a b} {string compare $a $b}

db1 collate mycollate mycollate_db1
db2 collate mycollate mycollate_db2

do_test 2.3 {
  set ::invoked_mycollate_db1 0
  db1 eval {
    CREATE TABLE t1(a COLLATE mycollate, CHECK (a IN ('one', 'two', 'three')));
    INSERT INTO t1 VALUES('one');
  }
  db1 close
  set ::invoked_mycollate_db1
} {1}
do_test 2.4 {
  set ::invoked_mycollate_db1 0
  db2 eval {
    INSERT INTO t1 VALUES('two');
  }
  db2 close
  set ::invoked_mycollate_db1
} {0}

sqlite3_enable_shared_cache $::enable_shared_cache
finish_test

do_test trigger1-1.12 {
  catchsql {
    create table t1(a,b);
    create trigger t1t instead of update on t1 for each row begin
      delete from t1 WHERE a=old.a+2;
    end;
  }
} {1 {cannot create INSTEAD OF trigger on table: main.t1}}

ifcapable view {
# Ensure that we cannot create BEFORE triggers on views
do_test trigger1-1.13 {
  catchsql {
    create view v1 as select * from t1;
    create trigger v1t before update on v1 for each row begin
      delete from t1 WHERE a=old.a+2;
    end;
  }
} {1 {cannot create BEFORE trigger on view: main.v1}}
# Ensure that we cannot create AFTER triggers on views
do_test trigger1-1.14 {
  catchsql {
    drop view v1;
    create view v1 as select * from t1;
    create trigger v1t AFTER update on v1 for each row begin
      delete from t1 WHERE a=old.a+2;
    end;
  }
} {1 {cannot create AFTER trigger on view: main.v1}}
} ;# ifcapable view

# Check for memory leaks in the trigger parser
#
do_test trigger1-2.1 {
  catchsql {
    CREATE TRIGGER r1 AFTER INSERT ON t1 BEGIN

do_test trigger1-1.12 {
  catchsql {
    create table t1(a,b);
    create trigger t1t instead of update on t1 for each row begin
      delete from t1 WHERE a=old.a+2;
    end;
  }
} {1 {cannot create INSTEAD OF trigger on table: t1}}

ifcapable view {
# Ensure that we cannot create BEFORE triggers on views
do_test trigger1-1.13 {
  catchsql {
    create view v1 as select * from t1;
    create trigger v1t before update on v1 for each row begin
      delete from t1 WHERE a=old.a+2;
    end;
  }
} {1 {cannot create BEFORE trigger on view: v1}}
# Ensure that we cannot create AFTER triggers on views
do_test trigger1-1.14 {
  catchsql {
    drop view v1;
    create view v1 as select * from t1;
    create trigger v1t AFTER update on v1 for each row begin
      delete from t1 WHERE a=old.a+2;
    end;
  }
} {1 {cannot create AFTER trigger on view: v1}}
} ;# ifcapable view

# Check for memory leaks in the trigger parser
#
do_test trigger1-2.1 {
  catchsql {
    CREATE TRIGGER r1 AFTER INSERT ON t1 BEGIN