mirror of
https://github.com/ramsey/uuid.git
synced 2026-06-14 15:56:48 +03:00
Ben Ramsey
33 lines
1.0 KiB
ReStructuredText
33 lines
1.0 KiB
ReStructuredText
.. _introduction:
|
|
|
|
============
|
|
Introduction
|
|
============
|
|
|
|
ramsey/uuid is a PHP library for generating and working with `RFC 4122`_ version
|
|
1, 2, 3, 4, and 5 universally unique identifiers (UUID). ramsey/uuid also
|
|
supports optional and non-standard features, such as `version 6 UUIDs`_,
|
|
GUIDs, and other approaches for encoding/decoding UUIDs.
|
|
|
|
What Is a UUID?
|
|
###############
|
|
|
|
A universally unique identifier, or UUID, is a 128-bit unsigned integer, usually
|
|
represented as a hexadecimal string split into five groups with dashes. The most
|
|
widely-known and used types of UUIDs are defined by `RFC 4122`_.
|
|
|
|
A UUID, when encoded in hexadecimal string format, looks like:
|
|
|
|
.. code-block:: text
|
|
|
|
ebb5c735-0308-4e3c-9aea-8a270aebfe15
|
|
|
|
The probability of duplicating a UUID is close to zero, so they are a great
|
|
choice for generating unique identifiers in distributed systems.
|
|
|
|
UUIDs can also be stored in binary format, as a string of 16 bytes.
|
|
|
|
|
|
.. _RFC 4122: https://tools.ietf.org/html/rfc4122
|
|
.. _version 6 UUIDs: http://gh.peabody.io/uuidv6/
|