Store Zip Code Title For Free

You are right that the United States Postal Service writes ?ZIP Code? with a capital C?and ZIP in all caps. You're also right about us. Though CMOS doesn't specifically rule on how to capitalize the term, it has rendered it as ?zip code? (all lowercase) since it first appeared in the Manual in 1982 (in the 13th ed.).

The right data type for a postal code is a string.

When it comes to USA zip codes, they are always 5 digits long. However, sometimes these codes may also include leading zeros. If you store these zip codes as integers, any leading zeros would be stripped, resulting in missing data. As such, it's usually better to store zip codes as 5 character strings.

The correct format for a numeric ZIP+4 code is five digits, a hyphen, and four digits. The first five digits represent the 5-digit ZIP Code; the sixth and seventh digits (the first two after the hyphen) identify an area known as a sector; the eighth and ninth digits identify a smaller area known as a segment.

A valid postal code depends on where you live. The specific order of the numbers of a ZIP code are important and can be used to help identify what state an individual lives in and where their mail is sorted. The first three digits of a ZIP code correspond to the central mail processing facility used to sort the mail.

Zip codes are always 5 characters, hence you would need a CHAR datatype, rather than VARCHAR. The first takes 5 bytes per zip code. The second takes only 3 bytes per zip code. The ZEROFILL option is necessary for zip codes with leading zeros.

CHAR data types are best used for storing data that is of a consistent length. For example, two-character State codes in the United States, single-character sex codes, phone numbers, postal codes, etc.