🚀 go-pugleaf

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;