CODEWITHSUNDEEP
pythonflasksqlalchemyalembicflask-migrate
Pav Sidhu
Pav Sidhu

Reputation: 6944

Can't migrate or upgrade database with Flask-Migrate (Alembic)

I've been using Flask-Migrate (Alembic) for updating my database. I updated my models.py file however I made an error. I ran a migration and went to upgrade the database, however I got this error:

sqlalchemy.exc.IntegrityError: (_mysql_exceptions.IntegrityError) (1215, 'Cannot add foreign key constraint') [SQL: u'\nCREATE TABLE topics (\n\tid INTEGER NOT NULL AUTO_INCREMENT, \n\t`subjectID` INTEGER, \n\ttopic VARCHAR(150) NOT NULL, \n\tPRIMARY KEY (id), \n\tFOREIGN KEY(`subjectID`) REFERENCES subjects (id)\n)\n\n']

What I had done was have db.Text instead of db.Integer for a foreign key.

When I try run a new migration I get this:

alembic.util.CommandError: Target database is not up to date.

So now I'm stuck. I cannot upgrade the database nor run a migration. I tried to downgrade to an older database version by using something like this:

python manage.py db downgrade --sql b877018671c:36949b1cca31

But when I run python manage.py db current I get the newest database version which I am stuck in.

Is there a fix for this? Thanks.

Upvotes: 17

Views: 34833

Answers (4)

user
user

Reputation: 1240

alembic.util.CommandError: Target database is not up to date.

Could you try the following steps?

python manage.py db stamp head
python manage.py db migrate
python manage.py db upgrade

'stamp' the revision table with the given revision; don't run any migrations

Upvotes: 15

Sebastian Villacis
Sebastian Villacis

Reputation: 9

The first step is remove the latest migrate version created, then you should use these commands:

 flask db stamp head
 flask db migrate -m "newMigration"
 flask db upgrade

Upvotes: 0

Taehan Stott
Taehan Stott

Reputation: 498

I feel like the accepted answer is a little over-complicated. I had this same issue and the way that I solved it was to simply delete the migration that contained the coding errors. You don't need it anyways since, again, it was coded incorrectly. Find the latest migration in the migrations/versions folder, delete it, then run your migration again and upgrade. You don't need to delete the data in your database just to migrate it.

Upvotes: 21

Sanna Keller-Heikkila
Sanna Keller-Heikkila

Reputation: 2594

Alembic stores the db version in a table it creates called alembic_version. This table contains a single field and row alembic_version.version_num. Make sure the value for this matches the filename of the most recent file in migrations/version. This version number is also contained inside the revision file in the revision variable that generally shows up on line 26 of the file. Make sure it matches the db version.

Another option is to simply drop the db and recreate it using alembic. If this is a development environment, where the data is not important, that would be my recommendation.

Upvotes: 23

Related Questions