delphitadoquery

How to pass parameters to an ADOQuery object?


I am using ADOQuery in Delphi 7 and Oracle. I am getting error while passing parameters to ADOQuery. I have used following line. Please help me to identify error.

ADOQuery.Sql.text:= 'select * from temp_table '+
        'where column1 in (select column from table2 where id=:id) and id=:id';
ADOQuery.Parameters.ParamByValue('id').value= 'abc';
ADOQuery.open;

when I open the query i will get following error:

Parameter object is improperly defined. Inconsistent or incomplete information is provided.


Solution

  • We have the same problem, we ended "masking" the class TParameters like this:

    Declaration:

    TMyParameter = class(TParameter)
    private
      function GetAsValue: variant;
      Procedure SetAsValue(const Value: variant);
    public
      property Value: variant read GetAsValue write SetAsValue;
    end;
    

    Implementation:

    procedure TMyParameter.SetAsValue(const Value: variant);
    var
      iPar: Integer;
    
    begin
      for iPar:= 0 to Collection.Count - 1 do
        if (Name = TParameter(Collection.Items[iPar]).Name) then
          TParameter(Collection.Items[iPar]).Value:= Value;
    end;
    
    function TMyParameter.GetAsValue: variant;
    begin
      Result:= inherited Value;
    end;
    

    And how to use:

    TMyParameter(ADOQuery.Parameters.ParamByName('id')).AsValue:= 'abc';
    

    I hope it helps.