Question

What is the correct column type for holding ZipCode values in PostgreSQL database?

Answer 1

It is something like xxxxx-xxxx, so varchar(10) is recommended.

If you want to check the syntax of the values in the database, you could create a domain type for zip codes.

CREATE DOMAIN zipcode varchar(10) 
    CONSTRAINT valid_zipcode 
    CHECK (VALUE ~ '[A-Z0-9-]+'); -- or a better regular expression

You could have a look at this site, which proposes this regex:

(^\d{5}(-\d{4})?$)|(^[ABCEGHJKLMNPRSTVXY]{1}\d{1}[A-Z]{1} *\d{1}[A-Z]{1}\d{1}$)

But you should check it works for the PostgreSQL regex syntax.