Support UUID4 and UUID7 on multiple databases

[LilyFirefly]

Code of Conduct

• I agree to follow Django's Code of Conduct

Feature Description

Introduce UUID4 and UUID7 database functions to allow use with db_default on multiple databases.

Problem

With the introduction of uuid version 7, Django users may wish to migrate to using version 7 as a db_default for model primary keys and other UUIDField instances.

Request or proposal

proposal

Additional Details

Uuid v4 and v7 are now available on multiple databases:

Postgres

• uuidv4 and uuidv7 from version 18.

Postgres also has gen_random_uuid which creates a uuid4 and we currently use in django.contrib.postgres.functions.RandonUUID.

MariaDB

• uuid_v4 since version 11.7
• uuid_v7 since version 11.7

Oracle

• uuid is a uuid v4 introduced in version 23ai.

Version 7 isn't supported yet.

Sqlite

Uuid v4 is available via an extension, but this is probably too difficult to support.

MySQL

Not yet supported. (There is a uuid function, but this creates v1 uuids.)

Implementation Suggestions

No response

[github-actions]

Thank you LilyFirefly for sharing your idea! We have a lot of them so please be patient. You can see the current queue here.

Community instructions

For commenters, please use the emoji reactions on the issue to express support, and/or concern easily. Please use the comments to ask questions or contribute knowledge about the idea. It is unhelpful to post comments of "I'd love this" or "What's the state of this?"

Reaction Guide

• 👍 This is something I would use
• 👎 This is something that would cause problems for me or Django
• 😕 I’m indifferent to this
• 🎉 This is an easy win

[andrew-cybsafe]

There are ways to create uuids in sqlite and MySQL that could be used to create a consistent db function.

For sqlite (source):

select lower(hex( randomblob(4)) || '-' || hex( randomblob(2))
         || '-' || '4' || substr( hex( randomblob(2)), 2) || '-'
         || substr('AB89', 1 + (abs(random()) % 4) , 1)  ||
         substr(hex(randomblob(2)), 2) || '-' || hex(randomblob(6))) 

For MySQL 8.0+ (source):

SELECT BIN_TO_UUID(
        RANDOM_BYTES(16)
        & 0xffffffffffff0fff3fffffffffffffff 
        | 0x00000000000040008000000000000000
    )

[carltongibson]

Let's bump it along.