How to enforce unique fk combinations in a linking (join) table

[enki]

Hello everyone,

I have a linking table with 3 fields (1 pk[row], and 2 fk[A___, B___]). How do i make the linking table with 2 parent tables, not allow duplicate foreign key rows in fmp?

--

This is bad (because row 1 and 3 are duplicates)

row A___ B___

1_pk a1_fk b1_fk

2_pk a2_fk b1_fk

3_pk a1_fk b1_fk

This is good (because the two foreign keys are never duplicated )

row A___ B___

1_pk a1_fk b1_fk

2_pk a2_fk b1_fk

3_pk a1_fk b2_fk

4_pk a2_fk b2_fk

Thanks for you help,

-enki

[comment]

I am not sure I understand this - I THINK you can find the answer here.

[enki]

your link was brilliant.

(and even better, you provided 2 solutions.. double thanks)

Thank you.