Question

I’m not sure if this should be a constraint or not, but I want the ‘UserName’ column of a table to ignore the value that is set when an insert or update is executed and instead, store the value of ‘DisplayUserName’ column converted to lowercase. And if ‘DisplayUserName’ is changed, ‘UserName’ should be updated as well to ‘DisplayUserName’ lowered.

Thanks!

Answer 1

The common way of doing this is using a trigger that fires on insert and update.

http://msdn.microsoft.com/en-us/magazine/cc164047.aspx

The code for the trigger should be something like this:

CREATE TRIGGER updateDisplayName_trigger ON Users FOR INSERT, UPDATE   AS IF UPDATE(UserName) UPDATE Users SET DisplayUserName = Lower(UserName) 

Just adjust it to your specific business rule, because I think I didn’t got it right =)