DjangoMapping strings to strings with HStoreField - a PostgreSQL specific field

Syntax

  • FooModel.objects.filter(field_name__key_name='value to query')

Remarks

Setting up HStoreField

First, we'll need to do some setup to get HStoreField working.

  1. make sure django.contrib.postgres is in your `INSTALLED_APPS
  2. Add HStoreExtension to your migrations. Remember to put HStoreExtension before any CreateModel or AddField migrations.
from django.contrib.postgres.operations import HStoreExtension
from django.db import migrations

class FooMigration(migrations.Migration):
    # put your other migration stuff here
    operations = [
        HStoreExtension(),
        ...
    ]

Adding HStoreField to your model

-> Note: make sure you set up HStoreField first before going on with this example. (above)

No parameters are required for initializing a HStoreField.

from django.contrib.postgres.fields import HStoreField
from django.db import models
    
class Catalog(models.model):
    name = models.CharField(max_length=200)
    titles_to_authors = HStoreField()

Creating a new model instance

Pass a native python dictionary mapping strings to strings to create().

Catalog.objects.create(name='Library of Congress', titles_to_authors={
    'Using HStoreField with Django': 'CrazyPython and la communidad',
    'Flabbergeists and thingamajigs': 'La Artista Fooista',
    'Pro Git': 'Scott Chacon and Ben Straub',
})

Performing key lookups

Catalog.objects.filter(titles__Pro_Git='Scott Chacon and Ben Straub')

Using contains

Pass a dict object to field_name__contains as a keyword argument.

Catalog.objects.filter(titles__contains={
        'Pro Git': 'Scott Chacon and Ben Straub'})
Equivalent to the SQL operator `@>`.