如何生成没有破折号的uuid [英] How to generate uuids without dashes

问题描述

我正在创建一个具有以下表定义的表

I am creating a table with the following table definition

CREATE TABLE auth(
    id                  UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    role                VARCHAR(64)
);

生成的 uuid 格式为 a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11 我知道 postgres 也接受不带连字符的 uuid.我们如何指定自动生成的 uuid 中没有连字符?

The uuids generated are in the form a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11 I know postgres also accepts uuids without hyphens. How can we specify the auto-generated uuids do not have hyphens in it?

推荐答案

这里有一个可行的解决方案，可以实现与您要求的接近的目标:

Here is a working solution to achieve something close to what you ask:

CREATE TABLE foo (
  ts TIMESTAMP WITH TIME ZONE,
  uuid VARCHAR DEFAULT REPLACE(uuid_generate_v4()::text, '-', '' )
); 

INSERT INTO foo ( ts ) VALUES ( now() );

BUT (and it is a big but) 在这里我们将 uuid 转换为 string 这意味着索引本身会更多比数字或真正的 uuid 昂贵.

BUT (and it is a big but) here we convert uuid to a string that means that the index itself will be much more expensive than a number or a real uuid.

在这篇文章中你可以找到一个很好的解释:
https://tomharrisonjr.com/uuid-or-guid-as-primary-keys-be-careful-7b2aa3dcb439

In this article you can find a good explanation:
https://tomharrisonjr.com/uuid-or-guid-as-primary-keys-be-careful-7b2aa3dcb439

据我所知，即使您尝试删除它们，Postgres 的 uuid 也会使用连字符:

As far as I know, Postgres' uuid uses hyphens even if you try to remove them:

CREATE TABLE foo (
  ts TIMESTAMP WITH TIME ZONE,
  queue UUID DEFAULT REPLACE(uuid_generate_v4()::text, '-', '' )::uuid,
);

INSERT INTO foo ( ts ) VALUES ( now() );

上面的示例在 Postgres 9.6 中运行良好，但是当我们转换回 uuid 时，连字符被添加回来.

The example above works just fine in Postgres 9.6, but when we cast back to uuid hyphens are added back.

这篇关于如何生成没有破折号的uuid的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！