South - django.db.utils.DatabaseError: table "myapp_tablename" already exists

Error?

I am trying to get started with South.

I had an existing database.

I added South (syncdb, schemamigration --initial).

I updated models.py to add a field.

I ran ./manage.py schemamigration myapp --auto

It seemed to find the field and said I could apply this with ./manage.py migrate myapp

Doing that gave the error:

django.db.utils.DatabaseError: table "myapp_tablename" already exists
tablename is the first table listed in models.py.

Solution!

1.Firstly check the migration number which is causing this. Lets assume it is: 0010.

2.You need to:

./manage.py schemamigration myapp --add-field MyModel.added_field
./manage.py migrate myapp
if there is more than one field missing you have to repeat it for each field.

3.Now you land with a bunch of new migrations so remove their files from myapp/migrations (0011 and further if you needed to add multiple fields).

4.Run this:

./manage.py migrate myapp 0010
Now try ./manage.py migrate myapp

If it doesn't fail you're ready. Just doublecheck if any field's aren't missing.

EDIT:

This problem can also occur when you have a production database for which you install South and the first, initial migration created in other enviorment duplicates what you already have in your db. The solution is much easier here:

Fake the first migration:

./manage migrate myapp 0001 --fake

Roll with the rest of migrations:

./manage migrate myapp