I can not get param value when Param.DataType = ftVariant

[Tugrul Tamturk]

Hi,

I want to get parameter with variant type from UniSQL.. When I set

for i := 0 to UniSql.Params.Count-1 do begin
UniSql.Params.ParamType := ptInputOutput;
UniSql.Params.DataType := ftVariant;
end;

UniSql.Execute;

This Code cause "Multiple-step OLE DB operation generated errors. Check each OLE DB status value, if available. No work was done.

Parameter[0] :KEYPARAM - invalid ParamType (Status = 1h)."

With ADODB.AdoCommand component, I can use ftVariant Params for get values...

Do you support this usage style?

Thanks.

[Tugrul Tamturk]

Hi,

I wrote a comparing code as follow:


procedure TForm1.Button2Click(Sender: TObject);
var V : Variant; S : String;
begin
//UNIDAC : Taking date type field value as variant parameter
UniSQL1.SQL.Text := 'SELECT :PR = ADATEFIELDNAME FROM ATABLE WHERE ATABLEID=123';
UniSQL1.Params[0].ParamType := ptInputOutput;
UniSQL1.Params[0].DataType := ftVariant;
UniSQL1.Execute;
V := UniSQL1.Params[0].Value;
S := VarToStr(V);
Memo1.Lines.Add('UniSql > Value: '+ S + ' :'+ VarTypeAsText(VarType(V)));

//ADO : Same code for ADO
ADOCommand1.CommandText := 'SELECT :PR = ADATEFIELDNAME FROM ATABLE WHERE ATABLEID=123';
ADOCommand1.Parameters[0].Direction := pdInputOutput;
ADOCommand1.Parameters[0].DataType := ftVariant;
ADOCommand1.Execute;
V := ADOCommand1.Parameters[0].Value;
S := VarToStr(V);
Memo1.Lines.Add('AdoCmd > Value: '+ S + ' :'+ VarTypeAsText(VarType(V)));

end;


And results are not same..

UniSql > Value: Aug 1 2008 10:07PM :OleStr
AdoCmd > Value: 01.08.2008 22:07:49 :Date


As I understand, ftVariant type parameter is not supported properly in UNIDAC... ADOCommand detect fieldtype correctly and get parameter value as Date type, and put into variant variable..

This is very sad.. Because this flexibility is very important for my project.

I adapt lots of code, and now I stop and wait for the solution...

I am waiting for Devart team support...

[Tugrul Tamturk]

I sent this problem to Devart Support.. But after 2 days no response!

[Dimon]

The point is that if parameter type is set to variant, SQL Server returns parameter value as OleString.
In order to solve this problem you can set ParamType to ftDateTime otherwise you should call the Prepare method before calling Execute.

[Tugrul Tamturk]

Thanks, it works..