I'm using NHibernate and c#. I have a psuedo lookup table in MSSQL (I didn't build these) which keeps track of which groups users are assigned to. It has the following:

userid
groupid
createdby
createdtime

I wanted to use cascades so I could just add/remove a group from a user, but I don't know how to update the createdby and createdtime in the lookup table. I'm thinking I will need to map a USER_GROUP object and do it myself.

Is this the right way to go, or is there a way to do cascades AND update/insert into the lookup table?