https://github.com/radusuciu/django-sqlfun
A Django app that lets you define custom SQL functions
https://github.com/radusuciu/django-sqlfun
django sql
Last synced: 5 months ago
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A Django app that lets you define custom SQL functions
- Host: GitHub
- URL: https://github.com/radusuciu/django-sqlfun
- Owner: radusuciu
- License: mit
- Created: 2023-02-06T03:06:45.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2024-03-01T19:18:01.000Z (over 2 years ago)
- Last Synced: 2025-11-06T16:21:50.906Z (8 months ago)
- Topics: django, sql
- Language: Python
- Homepage:
- Size: 148 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
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# Django SQL Fun
Django SQLFun allows you to define and manage custom SQL functions in code. When you change the function definitions and call `makemigrations`, it will generate migrations for any functions that have been added, removed, or changed. These function classes can also be used in Django querysets since the `SqlFun` class inherits from [`django.db.models.expressions.Func`](https://docs.djangoproject.com/en/5.0/ref/models/expressions/#func-expressions).
**Note**: I'm still developing this so there may be some rough edges. Breaking changes may happen.
## Installation
1. Install using your favorite python package manager, eg. `pip install django-sqlfun`.
2. Add `sqlfun` to `INSTALLED_APPS` in your django settings
3. Run `manage.py migrate`. This will set up any tables required by `sqlfun` to keep track of your custom funcitons
## Use
1. Define a custom function in a module that gets imported on project load (eg. `models.py`). See below for example, or the [`test_project`](tests/test_project).
2. Run `manage.py makemigrations`
3. Run `manage.py migrate`
### Example
Define a custom function in your `models.py`:
```python
# models.py
from sqlfun import SqlFun
from django.db.models import IntegerField
class BadSum(SqlFun):
"""Almost returns the sum of two numbers."""
app_label = 'test_project' # [optional] if omitted, sqlfun will atempt to auto-resolve it
sql = """
CREATE OR REPLACE FUNCTION bad_sum(
first integer,
second integer
) RETURNS integer as $$
SELECT first + second + 1;
$$
LANGUAGE sql
stable;
"""
output_field = IntegerField()
```
Then run `manage.py makemigrations` and `manage.py migrate` and you should be good to go. You can use it in SQL: `SELECT bad_sum(2, 2)`, or in a Python queryset like so: `MyModel.objects.annotate(foo=BadSum(Value(2), Value(2)))`.
### Notes
- SQL functions are normalized, so changes in white-space should not result in changes being detected
- the `--dry-run` and `--name` options of `makemigrations` are respected
## Development
These instructions assume a recent Ubuntu/Debian environment.
1. Clone the repository
2. If needed, install `python3-venv` and `python3-pip` packages
3. Create a virtual environment `python3 -m venv .venv`
4. Install `libpq-dev` package since `psycopg2` depends on it.
5. Install `pdm`: `pip3 install --user pdm`
6. Install dev dependencies with `pdm install --dev`
Testing also requires a recent install of docker which is used to spin up a test postgres instance.
## Credits
This project is inspired by two great projects: [`django-pgtrigger`](https://github.com/Opus10/django-pgtrigger) and [`django-pgviews`](https://github.com/mypebble/django-pgviews).