Normalization to 3NF

Question

Is the following table in 3NF:

Customer(CustomerID, CustomerName, DOB, Phone, Address)

I am specially interested to know if the address field should be in this table or should it be further decomposed.

Answer 1

To give a precise answer about what is in normal form and what isn't requires knowledge of what keys and dependencies are supposed to be in effect. Here we have only attribute names to go on so any direct answer to your question can only be guesswork.

My guess is that the Customer table specified is in 3NF. If CustomerID is the only key and if none of the other non-key attributes are determinants then the table as specified is in 3NF.

Answer 2

It depends on the relationship between the customer and the address. If one-to-one, then you are in 3NF. If not, then you need to split out the address into another table. An additional consideration is the relationship between the address and other entities? If other entities need customer addresses, you definitely need another table.