Add new UUID functions

[dveeden]

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What is changed, added or deleted? (Required)

Add documentation for UUID_V4(), UUID_V7(), UUID_VERSION() and UUID_TIMESTAMP().

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• This PR is translated from:
• Other reference link(s):

pingcap/tidb#65007

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• Delete files
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[gemini-code-assist]

Summary of Changes

Hello @dveeden, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly expands the documentation for TiDB's UUID-related functions. It introduces detailed explanations, usage examples, and references for UUID_V4(), UUID_V7(), UUID_VERSION(), and UUID_TIMESTAMP(), while also clarifying the behavior of the existing UUID() function. This update ensures users have clear and up-to-date information on generating and working with various UUID versions within TiDB.

Highlights

• New UUID Functions Documented: Added comprehensive documentation for the UUID_V4(), UUID_V7(), UUID_VERSION(), and UUID_TIMESTAMP() functions, enhancing the clarity and completeness of TiDB's UUID capabilities.
• Function Table Update: The miscellaneous functions table has been updated to include the newly documented UUID functions, making them discoverable within the function list.
• UUID() Function Clarification: The existing UUID() function's description was updated to explicitly state it returns a version 1 UUID and references the latest RFC 9562.

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[gemini-code-assist]

Code Review

This pull request adds valuable documentation for the new UUID functions (UUID_V4, UUID_V7, UUID_VERSION, UUID_TIMESTAMP). The new content is well-structured and informative. I've provided a few suggestions to enhance clarity, ensure consistency, and correct a minor copy-paste error, all in accordance with the repository's documentation style guide. My feedback primarily focuses on reordering items for better discoverability and rephrasing sentences for improved readability.

[dveeden]

@gemini-code-assist any more recommendations?

[gemini-code-assist]

Thanks for asking, @dveeden! I've taken a closer look at the changes, and this is a great addition to the documentation, significantly enhancing the clarity and completeness of TiDB's UUID capabilities. The examples provided are very helpful for understanding the new functions.

I have a few minor recommendations for further improvement:

• Consistency in Terminology: Ensure consistent use of "UUIDs" (plural) instead of "UUID's" (possessive) where appropriate.
• Typographical Corrections: A couple of minor typos were found.
• Clarity in Function Descriptions: A small suggestion to make one function description slightly more precise.

Here are the specific suggestions:

---

File: best-practices/uuid.md

• Line 24: "UUID's" should be "UUIDs".

[RFC 9562](https://datatracker.ietf.org/doc/html/rfc9562) defines 8 different versions of UUIDs. TiDB can store any version of UUID and can create v1, v4 and v7 UUIDs.

• Line 32: "creatad" should be "created".

UUIDv4 is created with the [`UUID_V4()`](/functions-and-operators/miscellaneous-functions.md#uuid_v4) function. This function does not store a timestamp and is fully random except for the bits that store the version and variant.

• Line 36: "modern aternative" should be "modern alternative".

UUIDv6 is a modern alternative to UUIDv1 that is field compatible with UUIDv1.

• Line 37: "functions" should be "function".

• Line 38: For consistency, consider using "UUIDv1" instead of "version 1 UUID" here, as you use "UUIDv7" later in the same sentence.

UUIDv7 is created with the [`UUID_V7()`](/functions-and-operators/miscellaneous-functions.md#uuid_v7) function. This function is meant as a modern alternative to UUIDv1 for applications that don't require a UUID that is field compatible.