🚀 go-pugleaf

sorry wrong group ...

"Hannes Danzl" <hannes@danzl.danzl.at> wrote in message
news:3c702e09$1_1@dnews...
> Hi all.
>
> when trying to open tables from an Oracle 8.1.x.y-ADO connection I get
> occasionally VarCMP errors. I've tracked it down to
> TCustomADODataset.UpdateIndexDefs. For some reason casting the values of
the
> SUnique and SAutoUpdate fields results in an invalid VarCMP. If that
happens
> for an index, all following indexdefs are not loaded, thus ending in an
> incomplete list. Ok, that may be due to an invalid IndexDef recordset, but
I
> think Delphi suold handle this gracefully and try to load following
indexes
> or even better cast them correctly.
>
> as a solution i've subclassed TAdoTable to TtvdADOTable and done the
> following. Do you see any problems with this? And where to I have to send
> this as a bugfix-proposal?
>
> type
>   TtvdADOTable = class(TADOTable)
>   protected
>     procedure UpdateIndexDefs; override;
>   end;
>
> implementation
>
> const
>   cfIndex      = 3;
>
> function SafeBool(aVariant: Variant): Boolean;
> begin
>   if VarIsNull(aVariant) then
>     result:=false
>   else
>     result:=varAsType(aVariant, varBoolean);
> end;
>
> type
>   TtvdADOCOmmand = class(TADOCOmmand); // get access to protected
> ActiveConnection prop
>
> // copy out of adodb.pas except marked changes
> procedure TtvdADOTable.UpdateIndexDefs;
> const
>   SUnique = 'UNIQUE';                      { Do not localize + 5 }
>   SIndexName = 'INDEX_NAME';
>   SColumnName = 'COLUMN_NAME';
>   SPrimaryKey = 'PRIMARY_KEY';
>   SAutoUpdate = 'AUTO_UPDATE';
>   SOrdinalPosition = 'ORDINAL_POSITION';
> var
>   IndexInfo: _Recordset;
>   aValue: Variant;
> begin
>   try
>     FieldDefs.Update;
>     IndexDefs.Clear;
>     if (CommandType in [cmdTable, cmdTableDirect]) and (CommandText <> '')
> then
>     begin
>       SetConnectionFlag(cfIndex, True);
>       try
>         IndexInfo :=
> ttvdADOCommand(Command).ActiveConnection.OpenSchema(adSchemaIndexes,
>           VarArrayOf([Unassigned, Unassigned, Unassigned, Unassigned,
> CommandText]),
>           EmptyParam);
>         while not IndexInfo.EOF do
>         begin
>           if TagVariant(IndexInfo.Fields[SOrdinalPosition].Value).ulVal >
1
> then
>             with IndexDefs.Find(IndexInfo.Fields[SIndexName].Value) do
>               Fields := Format('%s;%s', [Fields,
> IndexInfo.Fields[SColumnName].Value])
>           else
>             with IndexDefs.AddIndexDef do
>             begin
>               Name := VarToStr(IndexInfo.Fields[SIndexName].Value);
>               Fields := VarToStr(IndexInfo.Fields[SColumnName].Value);
>               aValue:=IndexInfo.Fields[SPrimaryKey].Value;
> //hd changes start
>               if SafeBool(IndexInfo.Fields[SPrimaryKey].Value) = True then
>                 Options := Options + [ixPrimary];
>               if SafeBool(IndexInfo.Fields[SUnique].Value) = True then
>                 Options := Options + [ixUnique];
>               if SafeBool(IndexInfo.Fields[SAutoUpdate].Value) = False
then
>                 Options := Options + [ixNonMaintained];
> //hd changes end
>             end;
>           IndexInfo.MoveNext;
>         end;
>       finally
>         SetConnectionFlag(cfIndex, False);
>       end;
>     end;
>   except
>     { do nothing }
>   end;
> end;
>
>
>