django-sqlfun 0.0.1

Django app that lets you define custom SQL functions

django-sqlfun

Django SQLFun allows you to define custom SQL functions in code which are then kept up to date in the database with every run of manage.py migrate.

Use

1. Install using your favorite python package manager, eg. pip install django-sqlfun
2. Add django_sqlfun to INSTALLED_APPS in your django settings.
3. Define a custom function in a module that gets imported on project load (eg. models.py). See below for example.
4. Run manage.py migrate

Example

from django_sqlfun import SqlFun

class BadSum(SqlFun):
    ""Almost returns the sum of two numbers."""
    
    sql = """
        CREATE OR REPLACE FUNCTION bad_sum(
            first integer,
            second integer
        ) RETURNS integer as $$
        SELECT first + second + 1;
        $$
        LANGUAGE sql
        stable;
    """

Planned Developments

This is alpha level software, and thus far only tested with Postgres.

• Add support for usage in Python code by inheriting from django.db.models.expressions.Func.
• Integrate into migrations system. Currently if you use functions that are defined through django-sqlfun in django migrations, you may experience errors since the latest version of that function will always be used. I believe this can be tackled with the same approach used by the django-pgtrigger project.
• Handle deleted custom functions. Currently if you delete a django-sqlfun function, it is not automatically deleted in the database itself. This could likely also be solved by integrating into the migrations system.

Ideas for improvement are welcome. Breaking changes are possible.

Credits

This project is inspired by two great projects: django-pgtrigger and django-pgviews.