![Gitter](https://badges.gitter.im/Join Chat.svg)
Adds first-class support for PostgreSQL Views in the Django ORM
Install via pip:
pip install django-pgviews
Add to installed applications in settings.py:
INSTALLED_APPS = (
# ...
'django_pgviews',
)
from django.db import models
from django_pgviews import view as pg
class Customer(models.Model):
name = models.CharField(max_length=100)
post_code = models.CharField(max_length=20)
is_preferred = models.BooleanField(default=False)
class Meta:
app_label = 'myapp'
class PreferredCustomer(pg.View):
projection = ['myapp.Customer.*',]
dependencies = ['myapp.OtherView',]
sql = """SELECT * FROM myapp_customer WHERE is_preferred = TRUE;"""
class Meta:
app_label = 'myapp'
db_table = 'myapp_preferredcustomer'
managed = False
NOTE It is important that we include the managed = False
in the Meta
so
Django 1.7 migrations don't attempt to create DB tables for this view.
The SQL produced by this might look like:
CREATE VIEW myapp_preferredcustomer AS
SELECT * FROM myapp_customer WHERE is_preferred = TRUE;
To create all your views, run python manage.py sync_pgviews
You can also specify field names, which will map onto fields in your View:
from django_pgviews import view as pg
VIEW_SQL = """
SELECT name, post_code FROM myapp_customer WHERE is_preferred = TRUE
"""
class PreferredCustomer(pg.View):
name = models.CharField(max_length=100)
post_code = models.CharField(max_length=20)
sql = VIEW_SQL
Sometimes your models change and you need your Database Views to reflect the new data. Updating the View logic is as simple as modifying the underlying SQL and running:
python manage.py sync_pgviews --force
This will forcibly update any views that conflict with your new SQL.
You can specify other views you depend on. This ensures the other views are
installed beforehand. Using dependencies also ensures that your views get
refreshed correctly when using sync_pgviews --force
.
Note: Views are synced after the Django application has migrated and adding models to the dependency list will cause syncing to fail.
Example:
from django_pgviews import view as pg
class PreferredCustomer(pg.View):
dependencies = ['myapp.OtherView',]
sql = """SELECT * FROM myapp_customer WHERE is_preferred = TRUE;"""
class Meta:
app_label = 'myapp'
db_table = 'myapp_preferredcustomer'
managed = False
Postgres 9.3 and up supports materialized views which allow you to cache the results of views, potentially allowing them to load faster.
However, you do need to manually refresh the view. To do this automatically, you can attach signals and call the refresh function.
Example:
from django_pgviews import view as pg
VIEW_SQL = """
SELECT name, post_code FROM myapp_customer WHERE is_preferred = TRUE
"""
class Customer(models.Model):
name = models.CharField(max_length=100)
post_code = models.CharField(max_length=20)
is_preferred = models.BooleanField(default=True)
class PreferredCustomer(pg.MaterializedView):
name = models.CharField(max_length=100)
post_code = models.CharField(max_length=20)
sql = VIEW_SQL
@receiver(post_save, sender=Customer)
def customer_saved(sender, action=None, instance=None, **kwargs):
PreferredCustomer.refresh()
You can define any table name you wish for your views. They can even live inside your own custom PostgreSQL schema.
from django_pgviews import view as pg
class PreferredCustomer(pg.View):
sql = """SELECT * FROM myapp_customer WHERE is_preferred = TRUE;"""
class Meta:
db_table = 'my_custom_schema.preferredcustomer'
managed = False
Django Version | Django-PGView Version |
---|---|
1.4 and down | Unsupported |
1.5 | 0.0.1 |
1.6 | 0.0.3 |
1.7 | 0.0.4 |
1.9 | 0.1.0 |
1.10 | 0.2.0 |