PostgreSQL 9.4.4 Documentation
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Chapter 43. PL/Python - Python Procedural Language

Table of Contents

43.1. Python 2 vs. Python 3

43.2. PL/Python Functions

43.3. Data Values

43.3.1. Data Type Mapping
43.3.2. Null, None
43.3.3. Arrays, Lists
43.3.4. Composite Types
43.3.5. Set-returning Functions

43.4. Sharing Data

43.5. Anonymous Code Blocks

43.6. Trigger Functions

43.7. Database Access

43.7.1. Database Access Functions
43.7.2. Trapping Errors

43.8. Explicit Subtransactions

43.8.1. Subtransaction Context Managers
43.8.2. Older Python Versions

43.9. Utility Functions

43.10. Environment Variables

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

To install PL/Python in a particular database, use CREATE EXTENSION plpythonu, or from the shell command line use createlang plpythonu dbname (but see also Section 43.1).

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 plpythonu. 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 plpythonu.

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.