Programming Microsoft® SQL Server® 2012

The THROW Statement

Error handling in T-SQL was very difficult to implement properly before SQL Server 2005 introduced the TRY/CATCH construct, a feature loosely based on .NET’s try/catch structured exception handling model. The CATCH block gives you a single place to code error handling logic in the event that a problem occurs anywhere inside the TRY block above it. Before TRY/CATCH, it was necessary to always check for error conditions after every operation by testing the built-in system function @@ERROR. Not only did code become cluttered with the many @@ERROR tests, developers (being humans) would too often forget to test @@ERROR in every needed place, causing many unhandled exceptions to go unnoticed.

In SQL Server 2005, TRY/CATCH represented ...