Question

Every Customer has a physical address and an optional mailing address. What is your preferred way to model this?

Option 1. Customer has foreign key to Address

    Customer   (id, phys_address_id, mail_address_id)    Address    (id, street, city, etc.) 

Option 2. Customer has one-to-many relationship to Address, which contains a field to describe the address type

    Customer   (id)    Address    (id, customer_id, address_type, street, city, etc.) 

Option 3. Address information is de-normalized and stored in Customer

    Customer   (id, phys_street, phys_city, etc. mail_street, mail_city, etc.) 

One of my overriding goals is to simplify the object-relational mappings, so I’m leaning towards the first approach. What are your thoughts?

Answer 1

I tend towards first approach for all the usual reasons of normalisation. This approach also makes it easier to perform data cleansing on mailing details.

If you are possibly going to allow multiple addresses (mail, residential, etc) or wish to be able to use effective dates, consider this approach

    Customer   (id, phys_address_id)    Cust_address_type (cust_id, mail_address_id, address_type, start_date, end_date)    Address    (id, street, city, etc.)