How Does It Work?¶
Django Evolution tracks all the apps in your Django project, recording information on the structure of models, their fields, indexes, and so on.
When you make any change to a model that would need to be reflected in the database, Django Evolution will tell you that you’ll need an evolution file to apply those changes, and will suggest one for you.
Evolution files describe one or more changes made to models in an app. They can:
Change the attributes on fields
Change the indexes or constraints on a model
Transition an app to Django’s migrations
Run arbitrary SQL
Django Evolution looks at the last-recorded state of your apps, the current state, and the evolution files. If those evolution files are enough to update the database to the current state, then Django Evolution will process them, turning them into an optimized list of SQL statements, and apply them to the database.
This can be done for the entire database as a whole, or for specific apps in the database.
Since some apps (particularly Django’s own apps) make use of migrations (on Django 1.7 and higher), Django Evolution will also handle applying those migrations. It will do this in cooperation with the evolution files that it also needs to apply. However, it’s worth pointing out that migrations are never optimized the way evolutions are (this is currently a limitation in Django).