Django Add Default Value

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

Supported Databases

MySQL (or compatible)
PostgreSQL
MSSQL (currently not tested)
CockroachDB

Installation

pip install django-add-default-value

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 a autogenerated Migration, that adds a new field

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

Example

Given the following migration:

BEFORE

from django.db import migrations, models

class Migration(migrations.Migration):
    dependencies = [
        ...
    ]

    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:

AFTER

from django.db import migrations, models

from django_add_default_value import AddDefaultValue

class Migration(migrations.Migration):
    dependencies = [
        ...
    ]

    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.

Contributing

First of all, thank you very much for contributing to this project. Please base your work on the master branch and target master in your pull request.

To succesfully use the dbshell management command (very useful for debugging), the client binaries for the respective database engines are needed.

Then install pipenv. Edit the Pipfile to select your Django version and the accompanying MS-SQL driver. Make sure you don't commit this change in any pull request - we always set it to the oldest supported version.

Once you've updated the Pipfile, run pipenv install --python 3 --dev. You should now have a working development environment as a virtualenv. To access it, run pipenv shell or prefix commands with pipenv run. For more information see the pipenv documentation.

Testing

Copy the relevant sample settings file in test_project to the file without .sample in it. Adjust the values to match your environment (or match your environment to the values).

You should now be able to run the tests using tox. Select your environment when needed, using the -e command line flag. See Tox's excellent documentation.

License

django-add-default-value is released under the Apache 2.0 License.

3YOURMIND / django-add-default-value

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