I have an asp.net page that allows users to insert new records into a table. When they enter the data, I want to do a search of the empnum field to ensure that value does not exist already in the system. So before inserting, the page searches the users table for the empnum entered by the user. If it exits, show a message stating it already exists. If not, insert the record. What is the best way to do this? I'm using C# code behind.