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Help me better understand: Primary Keys

Question asked by jbrown Expert on Mar 19, 2013
Latest reply on Mar 22, 2013 by Lemmtech

Hey all,

I posted recently about using employee IDs. A lot of people gave me great advice. But now my mind is wondering: Does every table need a primary key?

I understand that primary keys are needed for relationships. They have to be unique, and as I understand it are related to the foreign key, the same as the foreign key in the related table. Thus Table A has relationships in Table B through the primary key to the foreign key.

 

But what about that related table? If that table is an ending table, that is, it is simply a list of student grades or student behavior records, why does table B need to have a primary key? It already has the kids' IDs in there to relate back to the Table A. Table A is the One, and Table B is the many. and that's where it ends.

 

Forgive the ignorant question, but i realized in my tables, I don't include a primary key when I feel that table doesn't need to have a one-to-many relationship in it.

 

I assume i'm doing wrong and will fix that, but i ask again, what's the point of a primary key in a end-table, so to speak? Do you worry about Primary keys in utility tables?

thanks

jb

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