>I'm trying to refactor a poor DB design that has resulted in many duplicate rows. (about 80,000 rows out of 190,000 rows are dupes.
>I understand how to delete the duplicates, but I am unsure how to propogate the PK of the rows I keep to children of the duplicates, IOW I'm trying to map 1 onto many.
>
>Am I making any sense?
>
>Thanks for any ideas.

Should the PK become FK for the child table? What exactly is the problem here?

I think I got the problem now. You need to re-map all the children of the original duplicate records you deleted to the IDs which are left as unique.

Sounds to me you need to use temp table with the original IDs and the ID of the records which are left and then re-map everything.