Question

I’ve been fighting my initial decision since I’ve began work on my database. I’m debating whether or not I need a separate table for email addresses. My database looks like this:

people(id, first_name, last_name, email)
addresses(id, address, street, city, state, zip, latitude, longitude)
addresses_people(id, person_id, address_id)
phone_numbers(id, person_id, phone_number, type)

I figured I didn’t need a separate table for email addresses as I only wanted one per person regardless if they have more. The problem I’m seeming to have though is that some people will NOT have email addresses. Very often I will be storing children in the people table. Now it seems like it would be better design if I put the email addresses in a separate table to avoid the thousands of empty email fields I’ll have.

It’s a huge hassle to change this now as the app is already in production somewhat, but changing it now as opposed to a year or two from now would be exponentially easier. Is it worth a day or two to change the emails to another table?

Answer 1

In my opinion you are over-engineering. Optional email field is fine. Actually having a separate table might introduce much bigger overhead.

The only reason for a separate table is to model 1-N relationship if you expect the user to have more than one e-mail.