Skip to main content

Efficient tree-based datastructure for Django

Project description

Build Status Code Health Badge Documentation Status Test Coverage Version Badge License Badge

django-closuretree is an implementation of the closure tree technique for Django applications designed to provide efficient querying of tree-based structures in a relational database. Its goal is to reduce the number of queries required when querying the children or parents of a given object.

Given the following model:

class Node(models.Model):
    name = models.CharField(max_length=24)
    parent = models.ForeignKey('self', related_name='children')

The children of each model can be queried with:

Node.objects.get(name='A').children.all()

However, for recursive lookups, this results in a large number of queries. Instead, django-closuretree allows you to extract them all in one go:

from closuretree.models import ClosureModel

class Node(ClosureModel):
    name = models.CharField(max_length=24)
    parent = models.ForeignKey('self', related_name='children', null=True)

a = Node.objects.create(name='A')
Node.objects.create(name='B', parent=a)

Node.objects.get(name='A').get_descendants()

A single query will obtain all the descendants.

Quick Start

  • Install django-closuretree with pip install django-closuretree.

  • Inherit your models from closuretree.models.ClosureModel instead of django.db.models.Model.

That’s it. You can now use get_descendants() and get_ancestors() on a model instance.

If you’re adding this to an existing application that already has data in the database, you’ll need to run the rebuildtable() method of each model before the closure tree will be populated with the existing data:

Node.rebuildtable()

Contributing

To contribute, fork the repo, do your work, and issue a pull request. We ask that contributors adhere to PEP8 standards, and include full tests for all their code.

Project details


Download files

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

Source Distribution

django-closuretree-1.2.0.tar.gz (12.7 kB view hashes)

Uploaded source

Built Distributions

django_closuretree-1.2.0-py3-none-any.whl (12.0 kB view hashes)

Uploaded py3

django_closuretree-1.2.0-py2-none-any.whl (12.0 kB view hashes)

Uploaded py2

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