To create the database migrations, take a look at the following steps:
- When you create models in your new categories or ideas app, you have to create an initial migration that will create the database tables for your app. This can be done by using the following command:
(env)$ python manage.py makemigrations ideas
- The first time that you want to create all of the tables for your project, run the following command:
(env)$ python manage.py migrate
Run this command when you want to execute the new migrations for all of your apps.
- If you want to execute the migrations for a specific app, run the following command:
(env)$ python manage.py migrate ideas
- If you make some changes in the database schema, you will have to create a migration for that schema. For example, if we add a new subtitle field to the idea model, we can create the migration by using the following command:
(env)$ python manage.py makemigrations --name=subtitle_added ideas
However, the --name=subtitle_added field can be skipped because in most cases Django generates fairly self-explanatory default names.
- Sometimes, you may have to add to or change data in the existing schema in bulk, which can be done with a data migration, instead of a schema migration. To create a data migration that modifies the data in the database table, we can use the following command:
(env)$ python manage.py makemigrations --name=populate_subtitle
> --empty ideas
The --empty parameter tells Django to create a skeleton data migration, which you have to modify to perform the necessary data manipulation before applying it. For data migrations, setting the name is recommended.
- To list all of the available applied and unapplied migrations, run the following command:
(env)$ python manage.py showmigrations
The applied migrations will be listed with an [X] prefix. The unapplied ones will be listed with a [ ] prefix.
- To list all of the available migrations for a specific app, run the same command, but pass the app name, as follows:
(env)$ python manage.py showmigrations ideas