procedure Tfrm_clock_In.btn_enterClick(Sender: TObject);
var
          Today:TDateTime;
          Executed:boolean;
begin
Executed:= false;
Today:= Date;
tbl_employees.Open;
tbl_employees.First;
Repeat
        if strtoint(Edit_Employee_ID.text) = tbl_employeesEmployee_ID.value then
           begin
                tbl_shift.Open;
                tbl_shift.Last;
                repeat
                        if (strtoint(Edit_Employee_ID.text) = tbl_shiftEmployee_ID.value) and (tbl_shiftDate_.Value = Today) then
                           begin
                                if Datetostr(tbl_shiftTime_Out.value)='' then
                                        begin
                                                //sql to updae file with clock out time
                                                Executed:=true;
                                                showmessage('Clocked Out')
                                        end;
                           end
                        else tbl_shift.Prior;
                Until (Executed=true) or (tbl_shift.Bof); //until record update or no shift found
           end
        else tbl_employees.Next;
Until (Executed=true) or (tbl_employees.Eof);

if tbl_employees.Eof then showmessage('Invalid User ID'); //if don't find a matching employee number then invalid

If tbl_shift.Bof then //if don't find a record to update then create new one
        begin
                //sql to create a new record
        end;
        
end;