Best MySQL Table Structure: 2 Parents, 1 Child

Question

I have two parent tables, BusinessGroup and SocialGroup, and one child table, Members. A Member can belong to either parent, but not both.

As far as I can see, there ar

Answer 1

"parent tables" is probably a misnomer - in the relational model I'd flip your relationship. e.g. make members the master records table, and a join table that allows 1-1 mapping, so have a PK of member_id or whatever the right field is, and map to the FK in either BusinessGroup or SocialGroup.