Quick Answers: What is the UUID column type good for and what exactly is a UUID?

The question has come up a few times recently about what UUIDs are and what they’re good for. In this quick answers post I explain what they are and provide reference links to further material, as well as a Hasura Short video to implementation and use in Postgres & Hasura.

A Hasura Bit

UUID

UUID stands for a universally unique identifier. Another term which is common for a UUID, is the GUID, or globally unique identifier, which is the common term Microsoft created for their UUIDs. Just know, that a GUID is a UUID, it’s just company naming convention vs the standard industry naming convention.

UUID Format

The canonical textual representation, the 16 octets of a UUID are represented as 32 hexadecimal (base-016) digits. They’re displayed across five groups separated by hyphens in 8–4–4–4–12 format. Even though there are 32 hexadecimal digits, this makes a total of 36 characters for format display. If storing as a string for example, the string needs to be able to hold 36 characters.

Uses for a UUID

The first key use case for a UUID is to have something generate the UUID to use it as a completely unique value for use with a subset of related data. UUIDs are prefect for primary keys in a database, or simply any type of key to ensure uniqueness across a system.

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