---
title: "PL/Python — Python Procedural Language"
id: plpython
pg_version: "20devel"
---

<a id="plpython"></a>

# PL/Python — Python Procedural Language

## Table of Contents

- [44.1. PL/Python Functions](plpython-funcs.md)
- [44.2. Data Values](plpython-data.md)
  - [44.2.1. Data Type Mapping](plpython-data.md#plpython-data-type-mapping)
  - [44.2.2. Null, None](plpython-data.md#plpython-data-null)
  - [44.2.3. Arrays, Lists](plpython-data.md#plpython-arrays)
  - [44.2.4. Composite Types](plpython-data.md#plpython-data-composite-types)
  - [44.2.5. Set-Returning Functions](plpython-data.md#plpython-data-set-returning-funcs)
- [44.3. Sharing Data](plpython-sharing.md)
- [44.4. Anonymous Code Blocks](plpython-do.md)
- [44.5. Trigger Functions](plpython-trigger.md)
- [44.6. Event Trigger Functions](plpython-event-trigger.md)
- [44.7. Database Access](plpython-database.md)
  - [44.7.1. Database Access Functions](plpython-database.md#plpython-database-access-funcs)
  - [44.7.2. Trapping Errors](plpython-database.md#plpython-trapping)
- [44.8. Explicit Subtransactions](plpython-subtransaction.md)
  - [44.8.1. Subtransaction Context Managers](plpython-subtransaction.md#plpython-subtransaction-context-managers)
- [44.9. Transaction Management](plpython-transactions.md)
- [44.10. Utility Functions](plpython-util.md)
- [44.11. Python 2 vs. Python 3](plpython-python23.md)
- [44.12. Environment Variables](plpython-envar.md)

The PL/Python procedural language allows PostgreSQL functions and procedures to be written in the [Python language](https://www.python.org). 

To install PL/Python in a particular database, use `CREATE EXTENSION plpython3u`. 


> [!TIP]
> If a language is installed into `template1`, all subsequently created databases will have the language installed automatically.

PL/Python is only available as an "untrusted" language, meaning it does not offer any way of restricting what users can do in it and is therefore named `plpython3u`. A trusted variant `plpython` might become available in the future if a secure execution mechanism is developed in Python. The writer of a function in untrusted PL/Python must take care that the function cannot be used to do anything unwanted, since it will be able to do anything that could be done by a user logged in as the database administrator. Only superusers can create functions in untrusted languages such as `plpython3u`. 


> [!NOTE]
> Users of source packages must specially enable the build of PL/Python during the installation process. (Refer to the installation instructions for more information.) Users of binary packages might find PL/Python in a separate subpackage.