Unique SQL Inserts

Question

I have a Users table that has a unique restriction on the username (for obvious reasons).

I use EF 4.0 DAL to populate the database and in the process of coding the CreateUser () method.

It...

• It is better to catch a SqlException if I try to insert a username that already exists.
• Do I explicitly check the username before trying to insert it into the database?

If you could also indicate the reasons why it would be great!

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