Skip to main content

PostgreSQL partial indexes for Django

Project description

# django-partial-index

PostgreSQL partial (sometimes also called filtered or conditional) index support for Django.

## Install

`pip install django-partial-index`

Requires Django 1.11 or later.

## Usage

With `unique=True`, this can be used to create unique constraints for a subset of the rows.
For example, to enforce that each user can only have one non-deleted room booking at a time:

from partial_index import PartialIndex

class RoomBooking(models.Model):
user = models.ForeignKey(User)
room = models.ForeignKey(Room)
deleted_at = models.DateTimeField(null=True, blank=True)

class Meta:
# unique_together = [('user', 'room')] - Does not allow multiple deleted rows. Instead use:
indexes = [
PartialIndex(fields=['user', 'room'], unique=True, where='deleted_at IS NULL')

With unique=False, partial indexes can be used to optimise lookups that return only a small subset of the rows.
For example, on a job queue table with millions of completed, and very few pending jobs, it can be used to
speed up a "find next pending job" query:

from partial_index import PartialIndex

class Job(models.Model):
created_at = models.DateTimeField(auto_now_add=True)
is_complete = models.BooleanField(default=False)

class Meta:
indexes = [
PartialIndex(fields=['created_at'], unique=False, where='is_complete = false')

Of course, these (unique) indexes could be created by a handwritten [RunSQL migration](
But the constraints are part of the business logic, and best kept close to the model definitions.

## TODOs

* Add tests.
* Test on Python versions older than 3.6.
* Add import and version checks to print nice errors when Django 1.11 is not installed.
* Replace `where='some sql expression'` with [Django's query expressions]( that are checked for valid syntax and field names.
* Add support for SQLite.
* Eventually make this package obsolete by getting it merged into Django's contrib.postgres module.

Project details

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Files for django-partial-index, version 0.1.0
Filename, size File type Python version Upload date Hashes
Filename, size django_partial_index-0.1.0-py2.py3-none-any.whl (5.7 kB) File type Wheel Python version py2.py3 Upload date Hashes View
Filename, size django-partial-index-0.1.0.tar.gz (3.3 kB) File type Source Python version None Upload date Hashes View

Supported by

AWS AWS Cloud computing Datadog Datadog Monitoring Facebook / Instagram Facebook / Instagram PSF Sponsor Fastly Fastly CDN Google Google Object Storage and Download Analytics Huawei Huawei PSF Sponsor Microsoft Microsoft PSF Sponsor NVIDIA NVIDIA PSF Sponsor Pingdom Pingdom Monitoring Salesforce Salesforce PSF Sponsor Sentry Sentry Error logging StatusPage StatusPage Status page