Surely an easy question for those in the know...

I have a contacts table, and I'd like to ensure uniqueness across
first/middle/last name fields.  Each field is an nvarchar(255) - as
such, I can't create a regular index because the combined index size
is greater than 900 bytes.  I've briefly looked into Full-Text
indexing, but it seems to me that it's primarily for searching, and I
can't see how I can use it to enforce uniqueness.

Can I setup a full-text index to enforce uniqueness?  Do I need to
enforce this constraint in the app instead of the database?

Thanks for any tips.

Remi.