Chapter 48. PL/Python — Python Procedural Language

Table of Contents

48.1. PL/Python Functions
48.2. Data Values
48.2.1. Data Type Mapping
48.2.2. Null, None
48.2.3. Arrays, Lists
48.2.4. Composite Types
48.2.5. Set-Returning Functions
48.3. Sharing Data
48.4. Anonymous Code Blocks
48.5. Trigger Functions
48.6. Database Access
48.6.1. Database Access Functions
48.6.2. Trapping Errors
48.7. Explicit Subtransactions
48.7.1. Subtransaction Context Managers
48.8. Transaction Management
48.9. Utility Functions
48.10. Python 2 vs. Python 3
48.11. Environment Variables

The PL/Python procedural language allows PostgreSQL functions and procedures to be written in the Python language.

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.