determine record exist by exception of sql is Principles?

Question

I have a table with primary key and I want to insert new record to that . In my code , I check if record exists by exception. In sql store procedure I have insert code and surround by exception , in my application I execute that sp and want to insert new record , if my record exist in table , insert code got error

"The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Sup_Item_Sup_Item_Cat". The conflict occurred in database test, table test. The statement has been terminated."

and go to catch statement, In my application I check the error that was returned by sql, and show a message box to user that record is exist .

I want to know, is this way is Principles? or I must use if exist statement in sql ?

Answer 1

Exception should never be used when you can avoid it and return a value. Exception is a "stress" on a system and much slower than any other way.

Its customary for a SP to return 0 if everything is Ok and a negative value if there is an error. Either check your SP return code in application or use out parameter to determine problem. An error should be truly an error.