Functional dependencies for a relation with all prime attributes?

I am doing a database theory course as part of my CS degree, and we have to confirm a database we designed is in BCNF. I am trying to create the functional dependencies, but I don't know what to do when a relation is all prime. (All attributes are primary keys, like when you have a M:N relationship.)

For example, consider this relation:

Prod_Cat[name, category_ID, EPC]

Where name, category_id, and EPC are all primary keys.

How would I define the functional dependencies for this?


  • I'm not sure about the meaning of the columns in your table, but if your primary key consists of all the columns, you'll only have trivial functional dependencies of the form A->B with B being a subset of A. (If you had any other functional dependencies of the form A->B where B is not a subset of A, then B wouldn't be in the key.) Also, the table must be in BCNF (but may not be in 4NF).