I am starting in vb.net from VBA and coding a 3 Tier application.
I have a Basic Application Running and need to sort out the Validation and Exception control.
I am Validation the data in the UI.
Should I validate it again in
If I do validate the data at all layers then how do I deal with a validation error if one is found at the DAL module? - How can I send it back to the UI?
Does it Slow the application down if the data is validated 4 times?
Also How do I Control exceptions?
If the Database Procedure can't update the record how do I get that message back to the UI?