Using Standardized Encodings
There are many standardized encodings of commonly used words. For example, the United States Postal Service (USPS) encodes all U.S. states and possessions using a two‑character abbreviation. The lengths of the unabbreviated state and possession strings range from four characters (Guam, Iowa, Ohio, and Utah) to 30 characters (Federated States of Micronesia). While you could define a State column as CHARACTER(30) and compress its values, or as VARCHAR(30), the easiest and most compact method of denoting U.S. states and possessions is to use the two‑character USPS encodings.