Foreign Keys & Primary Keys

I know this is a simple question, but I just can't find a simple answer. I have two entities as follows with only their primary keys listed: TEA_REF CLASS_TEA ------------ ------------------ TEA_CD UNIT_NUM CLASS_NUM TEA_CD The relationship is TEA_REF(one) to CLASS_TEA(many) with the foreign key as TEA_CD in CLASS_TEA. Should I also have a separate index for CLASS_TEA.TEA_CD for that relationship? Or will it being a part of the primary key suffice for the relationship? Barry Stubbs Windham School District Barry Stubbs Windham School District bgs@alpha1.net