Quick Start

Install

This package is available on PyPI and Crate.io.

Install from PyPI with pip:

$ pip install django-simple-history

Configure

Settings

Add simple_history to your INSTALLED_APPS

INSTALLED_APPS = [
    # ...
    'simple_history',
]

The historical models can track who made each change. To populate the history user automatically you can add middleware to your Django settings:

MIDDLEWARE = [
    # ...
    'simple_history.middleware.HistoryRequestMiddleware',
]

If you do not want to use the middleware, you can explicitly indicate the user making the change as documented in Advanced Usage.

Models

To track history for a model, create an instance of simple_history.models.HistoricalRecords on the model.

An example for tracking changes on the Poll and Choice models in the Django tutorial:

from django.db import models
from simple_history.models import HistoricalRecords

class Poll(models.Model):
    question = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published')
    history = HistoricalRecords()

class Choice(models.Model):
    poll = models.ForeignKey(Poll)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)
    history = HistoricalRecords()

Now all changes to Poll and Choice model instances will be tracked in the database.

Existing Projects

For existing projects, you can call the populate command to generate an initial change for preexisting model instances:

$ python manage.py populate_history --auto

By default, history rows are inserted in batches of 200. This can be changed if needed for large tables by using the --batchsize option, for example --batchsize 500.

Integration with Django Admin

To allow viewing previous model versions on the Django admin site, inherit from the simple_history.admin.SimpleHistoryAdmin class when registering your model with the admin site.

This will replace the history object page on the admin site and allow viewing and reverting to previous model versions. Changes made in admin change forms will also accurately note the user who made the change.

_images/1_poll_history.png

Clicking on an object presents the option to revert to that version of the object.

_images/2_revert.png

(The object is reverted to the selected state)

_images/3_poll_reverted.png

Reversions like this are added to the history.

_images/4_history_after_poll_reverted.png

An example of admin integration for the Poll and Choice models:

from django.contrib import admin
from simple_history.admin import SimpleHistoryAdmin
from .models import Poll, Choice

admin.site.register(Poll, SimpleHistoryAdmin)
admin.site.register(Choice, SimpleHistoryAdmin)

Changing a history-tracked model from the admin interface will automatically record the user who made the change (see Advanced Usage).

Querying history

Querying history on a model instance

The HistoricalRecords object on a model instance can be used in the same way as a model manager:

>>> from polls.models import Poll, Choice
>>> from datetime import datetime
>>> poll = Poll.objects.create(question="what's up?", pub_date=datetime.now())
>>>
>>> poll.history.all()
[<HistoricalPoll: Poll object as of 2010-10-25 18:03:29.855689>]

Whenever a model instance is saved a new historical record is created:

>>> poll.pub_date = datetime(2007, 4, 1, 0, 0)
>>> poll.save()
>>> poll.history.all()
[<HistoricalPoll: Poll object as of 2010-10-25 18:04:13.814128>, <HistoricalPoll: Poll object as of 2010-10-25 18:03:29.855689>]

Querying history on a model class

Historical records for all instances of a model can be queried by using the HistoricalRecords manager on the model class. For example historical records for all Choice instances can be queried by using the manager on the Choice model class:

>>> choice1 = poll.choice_set.create(choice_text='Not Much', votes=0)
>>> choice2 = poll.choice_set.create(choice_text='The sky', votes=0)
>>>
>>> Choice.history
<simple_history.manager.HistoryManager object at 0x1cc4290>
>>> Choice.history.all()
[<HistoricalChoice: Choice object as of 2010-10-25 18:05:12.183340>, <HistoricalChoice: Choice object as of 2010-10-25 18:04:59.047351>]

Because the history is model, you can also filter it like regularly QuerySets, a.k. Choice.history.filter(choice_text=’Not Much’) will work!