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I have trouble with django model migrations. I have some models in my app, and I already have some data inside. When I added some models in my application, and I run makemigrations, the app report that there is no change. I know that sometimes some errors came when migrate, so I delete django_migrations table in my database and run makemigrations again, and now program found my new fields.

The problem now is that if I run migrate system tell me that some tables already exist. (Which is ok and correct, because they do). I don't want to delete those tables, because I have data already inside.

I can't run migrate --fake, because program will think that I already have all the tables, which is not true.

So, I am looking for a way to tell the program : run migration, if table exist skip it. (--fake it)

Another question is why is this happening to me, that makemigrations don't recognise my changes (some cache problems,...)?

Marko Zadravec
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  • Have a look at the [`--fake-initial`](https://docs.djangoproject.com/en/1.11/topics/migrations/#initial-migrations) option. – Alasdair Oct 26 '17 at 11:34

5 Answers5

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How about doing this way ?

python manage.py makemigrations

(Skip this step if you have already have migration file ready)

It will create migrations for that package lets say with a name like 0001_initial.py

Edit the file manually so that you delete all models there except that was already created in database.

Now you do a fake migration. This will sync your database with models.

python manage.py migrate --fake

Then run makemigrations again to have rest of the tables created along with a new migration file.

python manage.py makemigrations

Regarding your other question, Why makemigrations didn't recogonize your models can be because of reasons like:

  1. Migrations for those changes are already there in some migration file.
  2. You missed it to mention package_name in INSTALLED_APPS but i believe you did it here.
Ali Askar
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every time you make changes to your models, try these steps :

python manage.py makemigrations [your app name]

then:

python manage.py migrate

it should work fine. but remember if you have already data(rows) in your tables you should specify the default value for each one the queries.
if not, Django prompt you to specify the default value for them or you can just try to use blank=True or null=True in your fields like below :

website         = models.URLField(blank=True)
Farzan Ahmadi
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the possible cause or this is that you have another migration in the same folder starts with the same prefix... maybe you make another migration on the same table on another branch or commit so it's saved to the db with the same prefix ie: 00010_migration_from_commit_#10, 00010_migration_from_commit_#11

the solution for this is to rename the migration file like this 00011_migration_from_commit_#11

Ahmed AbdelSalam
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I tried to edit the related migration file and commented the part where it creates that specific column, then ran python manage.py migrate

Omid
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The main problem is the existing tables that are disabling the migration of the new tables, so the solution is straight-forward:

** Try to add managed = False to the existing dB so it won't be detected by migrate

** Redo it for all existing old tables :

class Meta:
    managed=False

It sometimes gets boring when we have a lot of tables in the same application but it works perfectly!

KaiserKatze
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Khalil Bouzir
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