Thanks for that Eric,
My idea was to be able to have 3 addresses for each contact, and manage those with the mrt insert, update.
So I understand now that is not possible if I use the same masterkey, that being the contactID..
Given that, should I add 2 additional tables to incorporate those extra addresses ?
or incorporate an additional relational table as in
1. contact has addresses
2. addresses has type
or some other way