47705a8968
* fix: rewrite relative URLs when syncing to GitHub discussion Relative URLs back to supabse.com won't work in GitHub discussions, so rewrite them back to absolute URLs starting with https://supabase.com * fix: replace all supabase urls with relative urls * chore: add linting for relative urls * chore: bump linter version * Prettier --------- Co-authored-by: Chris Chinchilla <chris.ward@supabase.io>
97 lines
2.5 KiB
Plaintext
97 lines
2.5 KiB
Plaintext
---
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id: 'uuid-ossp'
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title: 'uuid-ossp: Unique Identifiers'
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description: 'A UUID generator for PostgreSQL.'
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---
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The `uuid-ossp` extension can be used to generate a `UUID`.
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## Overview
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A `UUID` is a "Universally Unique Identifier" and it is, for practical purposes, unique.
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This makes them particularly well suited as Primary Keys. It is occasionally referred to as a `GUID`, which stands for "Globally Unique Identifier".
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## Enable the extension
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**Note**:
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Currently `uuid-ossp` extension is enabled by default and cannot be disabled.
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<Tabs
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scrollable
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size="small"
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type="underlined"
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defaultActiveId="dashboard"
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queryGroup="database-method"
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>
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<TabPanel id="dashboard" label="Dashboard">
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1. Go to the [Database](/dashboard/project/_/database/tables) page in the Dashboard.
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2. Click on **Extensions** in the sidebar.
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3. Search for `uuid-ossp` and enable the extension.
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</TabPanel>
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<TabPanel id="sql" label="SQL">
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```sql
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-- Example: enable the "uuid-ossp" extension
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create extension "uuid-ossp" with schema extensions;
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-- Example: disable the "uuid-ossp" extension
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drop extension if exists "uuid-ossp";
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```
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Even though the SQL code is `create extension`, this is the equivalent of "enabling the extension".
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To disable an extension, call `drop extension`.
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It's good practice to create the extension within a separate schema (like `extensions`) to keep the `public` schema clean.
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**Note**:
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Currently `uuid-ossp` extension is enabled by default and cannot be disabled.
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</TabPanel>
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</Tabs>
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## The `uuid` type
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Once the extension is enabled, you now have access to a `uuid` type.
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## `uuid_generate_v1()`
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Creates a UUID value based on the combination of computer’s MAC address, current timestamp, and a random value.
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<Admonition type="note">
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UUIDv1 leaks identifiable details, which might make it unsuitable for certain security-sensitive applications.
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</Admonition>
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## `uuid_generate_v4()`
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Creates UUID values based solely on random numbers. You can also use Postgres's built-in [`gen_random_uuid()`](https://www.postgresql.org/docs/current/functions-uuid.html) function to generate a UUIDv4.
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## Examples
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### Within a query
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```sql
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select uuid_generate_v4();
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```
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### As a primary key
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Automatically create a unique, random ID in a table:
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```sql
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create table contacts (
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id uuid default uuid_generate_v4(),
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first_name text,
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last_name text,
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primary key (id)
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);
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```
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## Resources
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- [Choosing a Postgres Primary Key](/blog/choosing-a-postgres-primary-key)
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- [The Basics Of Postgres `UUID` Data Type](https://www.postgresqltutorial.com/postgresql-uuid/)
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