[Django][Python]Django重置Migration
原文地址 ：https://simpleisbetterthancomplex.com/tutorial/2016/07/26/how-to-reset-migrations.html
本文描述了几张方法来重置老是出错的Django Migration
How to Reset Migration
The Django migration system was developed and optmized to work with large number of migrations. Generally you shouldn’t mind to keep a big amount of models migrations in your code base. Even though sometimes it causes some undesired effects, like consuming much time while running the tests. But in scenarios like this you can easily disable the migrations (although there is no built-in option for that at the moment).
Anyway, if you want to perform a clean-up, I will present a few options in this tutorial.
Scenario 1:
The project is still in the development environment and you want to perform a full clean up. You don’t mind throwing the whole database away.
- Remove the all migrations files within your project
Go through each of your projects apps migration folder and remove everything inside, except the__init__.pyfile.
Or if you are using a unix-like OS you can run the following script (inside your project dir):
find . -path "*/migrations/*.py" -not -name "__init__.py" -delete find . -path "*/migrations/*.pyc" -delete
- Drop the current database, or delete the
db.sqlite3if it is your case. - Create the initial migrations and generate the database schema:
python manage.py makemigrations python manage.py migrate
And you are good to go.
Scenario 2:
You want to clear all the migration history but you want to keep the existing database.
- Make sure your models fits the current database schema
The easiest way to do it is trying to create new migrations:
python manage.py makemigrations
If there are any pending migration, apply them first.
If you see the message:No changes detected
You are good to go.
- Clear the migration history for each app
Now you will need to clear the migration history app by app.
First run the showmigrations command so we can keep track of what is going on:
$ python manage.py showmigrations
Result:
admin [X] 0001_initial [X] 0002_logentry_remove_auto_add auth [X] 0001_initial [X] 0002_alter_permission_name_max_length [X] 0003_alter_user_email_max_length [X] 0004_alter_user_username_opts [X] 0005_alter_user_last_login_null [X] 0006_require_contenttypes_0002 [X] 0007_alter_validators_add_error_messages contenttypes [X] 0001_initial [X] 0002_remove_content_type_name core [X] 0001_initial [X] 0002_remove_mymodel_i [X] 0003_mymodel_bio sessions [X] 0001_initial
Clear the migration history (please note that core is the name of my app):
$ python manage.py migrate --fake core zero
The result will be something like this:
Operations to perform: Unapply all migrations: core Running migrations: Rendering model states... DONE Unapplying core.0003_mymodel_bio... FAKED Unapplying core.0002_remove_mymodel_i... FAKED Unapplying core.0001_initial... FAKED
Now run the command showmigrations again:
$ python manage.py showmigrations
Result:
admin [X] 0001_initial [X] 0002_logentry_remove_auto_add auth [X] 0001_initial [X] 0002_alter_permission_name_max_length [X] 0003_alter_user_email_max_length [X] 0004_alter_user_username_opts [X] 0005_alter_user_last_login_null [X] 0006_require_contenttypes_0002 [X] 0007_alter_validators_add_error_messages contenttypes [X] 0001_initial [X] 0002_remove_content_type_name core [ ] 0001_initial [ ] 0002_remove_mymodel_i [ ] 0003_mymodel_bio sessions [X] 0001_initial
You must do that for all the apps you want to reset the migration history.
3. Remove the actual migration files.
Go through each of your projects apps migration folder and remove everything inside, except for the __init__.py file.
Or if you are using a unix-like OS you can run the following script (inside your project dir):
find . -path "*/migrations/*.py" -not -name "__init__.py" -delete find . -path "*/migrations/*.pyc" -delete
PS: The example above will remove all the migrations file inside your project.
Run the showmigrations again:
$ python manage.py showmigrations
Result:
admin [X] 0001_initial [X] 0002_logentry_remove_auto_add auth [X] 0001_initial [X] 0002_alter_permission_name_max_length [X] 0003_alter_user_email_max_length [X] 0004_alter_user_username_opts [X] 0005_alter_user_last_login_null [X] 0006_require_contenttypes_0002 [X] 0007_alter_validators_add_error_messages contenttypes [X] 0001_initial [X] 0002_remove_content_type_name core (no migrations) sessions [X] 0001_initial
4. Create the initial migrations
$ python manage.py makemigrations
Result:
Migrations for ‘core‘:
0001_initial.py:
- Create model MyModel5. Fake the initial migration
In this case you won’t be able to apply the initial migration because the database table already exists. What we want to do is to fake this migration instead:
$ python manage.py migrate --fake-initial
Result:
Operations to perform: Apply all migrations: admin, core, contenttypes, auth, sessions Running migrations: Rendering model states... DONE Applying core.0001_initial... FAKED
Run showmigrations again:
admin [X] 0001_initial [X] 0002_logentry_remove_auto_add auth [X] 0001_initial [X] 0002_alter_permission_name_max_length [X] 0003_alter_user_email_max_length [X] 0004_alter_user_username_opts [X] 0005_alter_user_last_login_null [X] 0006_require_contenttypes_0002 [X] 0007_alter_validators_add_error_messages contenttypes [X] 0001_initial [X] 0002_remove_content_type_name core [X] 0001_initial sessions [X] 0001_initial
And we are all set up ??