Search code examples
c#.netarchitecturelayered

Where should I handle the exceptions, in the BLL, DAL or PL?

Which is the best place to handle the exceptions ? BLL, DAL or PL ?

Should I allow the methods in the DAL and BLL to throw the exceptions up the chain and let the PL handle them? or should I handle them at the BLL ?

e.g

If I have a method in my DAL that issues "ExecuteNonQuery" and updates some records, and due to one or more reason, 0 rows are affected. Now, how should I let my PL know that whether an exception happened or there really was no rows matched to the condition. Should I use "try catch" in my PL code and let it know through an exception, or should I handle the exception at DAL and return some special code like (-1) to let the PL differentiate between the (exception) and (no rows matched condition i.e. zero rows affected) ?

Solution

  • It makes no sense to let an exception that is thrown in the DAL bubble up to the PL - how is the user supposed to react if the database connection could not be established?

    Catch and handle exceptions early, if you can handle them. Do not just swallow them without outputting a hint or a log message - this will lead to severe difficulties and bugs that are hard to track.