Can someone tell me why the USERS table in the security database has a
unique index on the field USER_NAME instead of a unique contraint? I
remember talk about these two avenues and their use but from my memory of
these conversations I was under the impression that contraint in this
situation was considered suprerior for this purpose than just a unique
index.

Also - I plan to try a security database replication methodology and I
intend to add a PK type integer to the USERS table for the purpose. (plus a
trigger and generator of course, for it).
Can anyone tell me if this is going to cause a problem?

thanks
Alan