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https://github.com/isotoma/django-postgres

First-class Postgres feature support for the Django ORM.
https://github.com/isotoma/django-postgres

Last synced: 3 months ago
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First-class Postgres feature support for the Django ORM.

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README 

        
django-postgres

===============



Adds first-class support for [PostgreSQL][] features to the Django ORM.



Planned features include:



*   [Arrays][pg-arrays]

*   [Enums][pg-enums]

*   [Constraints][pg-constraints]

*   [Triggers][pg-triggers]

*   [Domains][pg-domains]

*   [Composite Types][pg-ctypes]

*   [Views][pg-views]



[postgresql]: http://www.postgresql.org/

[pg-arrays]: http://www.postgresql.org/docs/9.1/static/arrays.html

[pg-enums]: http://www.postgresql.org/docs/9.1/static/datatype-enum.html

[pg-constraints]: http://www.postgresql.org/docs/9.1/static/ddl-constraints.html

[pg-triggers]: http://www.postgresql.org/docs/9.1/static/sql-createtrigger.html

[pg-domains]: http://www.postgresql.org/docs/9.1/static/sql-createdomain.html

[pg-ctypes]: http://www.postgresql.org/docs/9.1/static/rowtypes.html

[pg-views]: http://www.postgresql.org/docs/9.1/static/sql-createview.html



Obviously this is quite a large project, but I think it would provide a huge

amount of value to Django developers.



Why?

----



PostgreSQL is an excellent data store, with a host of useful and

efficiently-implemented features. Unfortunately these features are not exposed

through Django's ORM, primarily because the framework has to support several

SQL backends and so can only provide a set of features common to all of them.



The features made available here replace some of the following practices:



-  Manual denormalization on `save()` (such that model saves may result in

   three or more separate queries).

-  Sequences represented by a one-to-many, with an `order` integer field.

-  Complex types represented by JSON in a text field.



Example

-------



The following represents a whirlwind tour of potential features of the project:



```python

from django.db import models

import django_postgres as pg



USStates = pg.Enum('states_of_the_usa', ['AL', ..., 'WY'])



class Address(pg.CompositeType):

    line1 = models.CharField(max_length=100)

    line2 = models.CharField(max_length=100, blank=True)

    city = models.CharField(max_length=100)

    zip_code = models.CharField(max_length=10)

    state = USStates()

    country = models.CharField(max_length=100)



class USPhoneNumber(pg.Domain):

    data_type = models.CharField(max_length=10)

    constraints = [

      r"VALUE ~ '^\d{3}-?\d{3}-?\d{4}$'"

    ]



class Customer(models.Model):

    name = models.CharField(max_length=100)

    shipping_address = Address()

    telephone_numbers = pg.Array(USPhoneNumber())

    is_preferred = models.BooleanField(default=False)



class PreferredCustomer(pg.View):

    projection = ['myapp.Customer.*']

    sql = """SELECT * FROM myapp_customer WHERE is_preferred = TRUE;"""

```



The SQL produced by this might look like:



```postgresql

CREATE TYPE states_of_the_usa AS ENUM ('AL', ..., 'WY');



CREATE TYPE myapp_address AS (

    line1 varchar(100),

    line2 varchar(100),

    city varchar(100),

    zip_code varchar(10),

    state states_of_the_usa,

    country varchar(100)

);



CREATE DOMAIN myapp_usphonenumber AS varchar(10)

    CHECK(VALUE ~ '^\d{3}-?\d{3}-?\d{4}$');



CREATE TABLE myapp_customer (

    id SERIAL PRIMARY KEY,

    shipping_address myapp_address,

    telephone_numbers myapp_usphonenumber[]

);



CREATE VIEW myapp_preferredcustomer AS

SELECT * FROM myapp_customer WHERE is_preferred = TRUE;

```



To create all your views, run ``python manage.py sync_pgviews``