Question

How can i pass the different types of errors from Data access layer to presentation layer?

suppose if we take the northwind database

scenario

I want to delete the customer, so i selected one customer in ui and clicked the “delete” button.It internally calls the “delete” in data access layer.

The prerequisite for deleting the customer is that the customer doesn’t have any orders.So in data access layer we wil check whether that customer has any orders.If the customer has orders how can we pass the message from dal to presentation layer that the customer has orders and we don’t delete.

Am i doing right?is there any other ways to deal with this type?

Thanks in advance

Answer 1

The other answers tell you how you should be implementing this particular scenario, however to answer your original question, the answer is to define your own exceptions.

You can have a core DataLayerException as the base for all of you data exceptions (inheriting from ApplicationException or similar) then have sub exceptions based on the scenario, e.g.:

• ConnectionClosedException
• TImeoutException

etc.