Primary key with 3 fields

[obhobh]

Hi, I have 3 tables named size, paper & weight. Each table is related to one another through many to many relationship.

a type of paper can have different weight and size. a particular size and weight can apply to different type of paper.

If the many to many relationship only involve 2 tables, I can create another table with a joint primary key to solve the problems. but since right now it involve 3 tables, can create another table and use 3 primary keys to create a joint primary key so that each paper is unique???

[bpat1434]

This would be better suited in the Database thread as there's no code to deal with here.

But I think I'll take a stab at it:

You have 3 tables, all with a relationship.

You say that if you have two, you can have one that will have the "unique" indexes of the other two tables.

So why not expand it, and say:

Table 1----------+
                 |
                 +--- Rel 1 ---+
                 |             |
Table 2----------+             +--- Unique Table
                 |             |
                 +--- Rel 2 ---+
                 |
Table 3----------+

Would that not work?

~Brett