Django Add Default Value for PostgreSQL

Django Migration Operation that can be used to transfer a field's default value to the database scheme.

Based on django-add-default-value by 3YOURMIND. This variant drops support for other databases, specifically the Azure ODBC driver which does not support current versions of Django.

Dependencies

• Python 3.6, 3.7, or 3.8
• Django 2.2 or 3.0

Installation

pip install django-add-default-value-postgresql

You can then use AddDefaultValue in your migration file to transfer the default values to your database. Afterwards, it's just the usual ./manage.py migrate.

Usage

Add this manually to an autogenerated Migration that adds a new field:

AddDefaultValue(
    model_name='my_model',
    name='my_field',
    value='my_default'
)

Example

Given the following migration:

operations = [
    migrations.AddField(
        field=models.CharField(default='my_default', max_length=255),
        model_name='my_model',
        name='my_field',
    ),
]

Modify the migration to add a default value:

+from django_add_default_value import AddDefaultValue
+
 operations = [
     migrations.AddField(
         field=models.CharField(default='my_default', max_length=255),
         model_name='my_model',
         name='my_field',
     ),
+    AddDefaultValue(
+        model_name='my_model',
+        name='my_field',
+        value='my_default'
+    )
 ]

If you check python manage.py sqlmigrate [app name] [migration], you will see that the default value now gets set.

Testing

You can test against multiple versions of Django using tox. To test across Python versions, use pyenv to run tox under each version.

License

django-add-default-value-postgresql is released under the Apache 2.0 License, based on django-add-default-value by 3YOURMIND which is also released under the Apache 2.0 License.

Changes from original source

• removed MySQL-related code
• removed MSSQL-related code
• added allow_migrate_model check on database_forwards and database_backwards
• added support for Python 3.7 and 3.8, dropped support for <3.6
• added support for Django 2.2 and 3.0, dropped support for <2.2