sp_addmessage allows one to optionally specify an error severity level, RAISERRROR requires it. I don't
see what the point of assigning a severity level when using sp_addmessage, because I'm going to have
to specify it again when using RAISERROR as it is oblivious to the error numbers assocated severity
The only way it makes sense to me is that before I use a custom error message that I query the sysmessages
table to see what severity level was used when the message was added, then use that severity level in
the RAISERROR call. Am I missing something? Do people actually use severity level this way?