What is bdc_ok code.
ok_code is generally used in screen as of I have used. You will define the function in the screen. and you can use it in the main program.
ok_code acts just as a temporary variable that stores the value of sy-ucomm.
When user interacts with the screen elements, the function code that you have assigned is filled in the sy-ucomm field which is turn gets reflected in OK_CODE.