Yuk, I don't like the sound of that. If you are bringing all of the details into a temp table first and then processing from there out to master/child tables, what I would do is use the PK on the temp table to help you avoid RBAR updates ....

Add another indexed field to your master table and, when you create your master records, populate this field with the PK from the temp table.

Then, when you create your child records, you can look up the 'proper' FK from the master table via the new temp PK field on the master table. You should be able to do this as a set-based create, vastly speeding things up.

Hope that makes sense.