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>
159 lines
3.7 KiB
Plaintext
159 lines
3.7 KiB
Plaintext
---
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id: 'plv8'
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title: 'plv8: JavaScript Language'
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description: 'JavaScript language for PostgreSQL.'
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---
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<Admonition type="deprecation">
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The `plv8` extension is deprecated in projects using Postgres 17. It continues to be supported in projects using Postgres 15, but will need to dropped before those projects are upgraded to Postgres 17. See the [Upgrading to Postgres 17 notes](/docs/guides/platform/upgrading#upgrading-to-postgres-17) for more information.
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</Admonition>
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The `plv8` extension allows you use JavaScript within Postgres.
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## Overview
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While Postgres natively runs SQL, it can also run other procedural languages.
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`plv8` allows you to run JavaScript code - specifically any code that runs on the [V8 JavaScript engine](https://v8.dev).
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It can be used for database functions, triggers, queries and more.
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## Enable the extension
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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 "plv8" 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 "plv8" extension
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create extension plv8;
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-- Example: disable the "plv8" extension
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drop extension if exists plv8;
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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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Procedural languages are automatically installed within `pg_catalog`, so you don't need to specify a schema.
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</TabPanel>
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</Tabs>
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## Create `plv8` functions
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Functions written in `plv8` are written just like any other Postgres functions, only
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with the `language` identifier set to `plv8`.
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```sql
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create or replace function function_name()
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returns void as $$
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// V8 JavaScript
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// code
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// here
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$$ language plv8;
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```
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You can call `plv8` functions like any other Postgres function:
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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="sql"
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queryGroup="language"
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>
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<TabPanel id="sql" label="SQL">
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```sql
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select function_name();
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```
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</TabPanel>
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<TabPanel id="js" label="JavaScript">
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```js
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const { data, error } = supabase.rpc('function_name')
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```
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</TabPanel>
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<$Show if="sdk:kotlin">
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<TabPanel id="kotlin" label="Kotlin">
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```kotlin
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val data = supabase.postgrest.rpc("function_name")
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```
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</TabPanel>
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</$Show>
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</Tabs>
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## Examples
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### Scalar functions
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A [scalar function](https://plv8.github.io/#scalar-function-calls) is anything that takes in some user input and returns a single result.
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```sql
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create or replace function hello_world(name text)
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returns text as $$
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let output = `Hello, ${name}!`;
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return output;
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$$ language plv8;
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```
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### Executing SQL
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You can execute SQL within `plv8` code using the [`plv8.execute` function](https://plv8.github.io/#plv8-execute).
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```sql
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create or replace function update_user(id bigint, first_name text)
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returns smallint as $$
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var num_affected = plv8.execute(
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'update profiles set first_name = $1 where id = $2',
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[first_name, id]
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);
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return num_affected;
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$$ language plv8;
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```
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### Set-returning functions
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A [set-returning function](https://plv8.github.io/#set-returning-function-calls) is anything that returns a full set of results - for example, rows in a table.
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```sql
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create or replace function get_messages()
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returns setof messages as $$
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var json_result = plv8.execute(
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'select * from messages'
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);
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return json_result;
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$$ language plv8;
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select * from get_messages();
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```
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## Resources
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- Official [`plv8` documentation](https://plv8.github.io/)
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- [plv8 GitHub Repository](https://github.com/plv8/plv8)
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