Quick introduction to PL/Python

In the previous chapters, we discussed PL/pgSQL which is one of the standard procedural languages distributed with PostgreSQL. PL/pgSQL is a language unique to PostgreSQL and was designed to add blocks of computation and SQL inside the database. While it has grown in its breath of functionality, it still lacks the completeness of syntax of a full programming language. PL/Python allows your database functions to be written in Python with all the depth and maturity of writing a Python code outside the database.

A minimal PL/Python function

Let's start from the very beginning (again):

CREATE FUNCTION hello(name text)
  RETURNS text
AS $$
    return 'hello %s !' %  name
$$ LANGUAGE plpythonu;

Here, we see that creating the function starts by defining it as any other PostgreSQL function with a RETURNS definition of a text field:

CREATE FUNCTION hello(name text)
  RETURNS text

The difference from what we have seen before is that the language part is specifying plpythonu...