Django Postgres composite types
pip install django-postgres-composite-types
Then add 'postgres_composite_types' to your
INSTALLED_APPS = [ # ... Other apps 'postgres_composite_types', ]
Define a type and add it to a model:
from django.db import models from postgres_composite_type import CompositeType class Address(CompositeType): """An address.""" address_1 = models.CharField(max_length=255) address_2 = models.CharField(max_length=255) suburb = models.CharField(max_length=50) state = models.CharField(max_length=50) postcode = models.CharField(max_length=10) country = models.CharField(max_length=50) class Meta: db_type = 'x_address' # Required class Person(models.Model): """A person.""" address = Address.Field()
An operation needs to be prepended to your migration:
import address from django.db import migrations class Migration(migrations.Migration): operations = [ # Registers the type address.Address.Operation(), migrations.AddField( model_name='person', name='address', field=address.Address.Field(blank=True, null=True), ), ]
class Card(CompositeType): """A playing card.""" suit = models.CharField(max_length=1) rank = models.CharField(max_length=2) class Meta: db_type = 'card' class Hand(models.Model): """A hand of cards.""" cards = ArrayField(base_field=Card.Field())
class Point(CompositeType): """A point on the cartesian plane.""" # pylint:disable=invalid-name x = models.IntegerField() y = models.IntegerField() class Meta: db_type = 'x_point' # Postgres already has a point type class Box(CompositeType): """An axis-aligned box on the cartesian plane.""" class Meta: db_type = 'x_box' # Postgres already has a box type top_left = Point.Field() bottom_right = Point.Field()
Gotchas and Caveats
The migration operation currently loads the current state of the type, not
the state when the migration was written. A generic
which takes the fields of the type would be possible, but it would still
require manual handling still as Django's
makemigrations is not currently
Changes to types are possible using
RawSQL, for example:
operations = [ migrations.RunSQL([ "ALTER TYPE x_address DROP ATTRIBUTE country", "ALTER TYPE x_address ADD ATTRIBUTE country integer", ], [ "ALTER TYPE x_address DROP ATTRIBUTE country", "ALTER TYPE x_address ADD ATTRIBUTE country varchar(50)", ]), ]
However, be aware that if your earlier operations were run using current DB code, you will already have the right types (bug #8).
It is recommended to that you namespace your custom types to avoid conflict with future PostgreSQL types.
(c) 2016, Danielle Madeley firstname.lastname@example.org
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