IBQuery – при returning не найдет параметр

var
  q: integer;
begin
IBQuery1.Close;
IBQuery1.SQL.Clear;
IBQuery1.SQL.Text := 'insert into Tab (ID, STR) values (GEN_ID(GN, 1), :STR) returning ID';
IBQuery1.Params[0].AsString := 'qwe';
IBQuery1.Open;
IBTransaction1.CommitRetaining;
q := IBQuery1.Fields[0].Value;

q := IBQuery1.Fields[0].Value;

var
  q: integer;
begin
IBQuery1.Close;
IBQuery1.SQL.Clear;
 
with IBQuery1.FieldDefs.AddFieldDef do
      begin
         DataType := ftInteger;
          Name := 'ID';
      end;
 
IBQuery1.SQL.Text := 'insert into Tab (ID, STR) values (GEN_ID(GN, 1), :STR) returning ID';
IBQuery1.Params[0].AsString := 'qwe';
IBQuery1.Open;
//IBTransaction1.CommitRetaining;
q := IBQuery1.Fields[0].Value;

var
  q : integer;
begin
  //IBQuery1.Close;
  //IBQuery1.SQL.Clear; //обе строки не нужны
 
    IBQuery1.SQL.Text := 'insert into Tab (ID, STR) values (GEN_ID(GN, 1), :STR) returning ID';
    IBQuery1.Params[0].Value := 'qwe';
  try
    IBQuery1.Transaction.StartTransaction;
    IBQuery1.ExecSQL;
    IBQuery1.Transaction.Commit;
  except
    IBQuery1.Transaction.Rollback;
    Exit;
  end;
  q := IBQuery1['id'];

var
  id : integer;
begin
  IBQuery1.SQL.Text := 'SELECT GEN_ID(GN, 1) AS ID FROM RDB$DATABASE';
  IBQuery1.Open;
  ID := IBQuery1['ID']; //идентификатор новой записи
  IBQuery1.Close;
 
  IBQuery1.Transaction.StartTransaction;
  IBQuery1.SQL.Text := 'insert into Tab (ID, STR) values (ID, :STR)';
  IBQuery1.Params[0].Value := 'qwe';
  IBQuery1.ExecSQL;
  IBQuery1.Transaction.Commit;
end;

  IBQuery1.SQL.Text := 'insert into Tab (ID, STR) values ('+IntToStr(ID)+', :STR)';