Renaming Django model field

Question

I'm trying to convert one of my model fields (units) from FloatField to an IntegerField.

My strategy is this:

1. Add '_units' field (IntegerField)
2. Copy data from 'units' to '_units'
3. Remove 'units'
4. Rename '_units' as 'units'

Migrations for steps 1 - 3 run fine but at Step 4 I get an error when I run the tests:

django.db.utils.OperationalError: no such column: myapp_mymodel._units

For this step I made an empty migration then added to the operations;

migrations.RenameField('MyModel', '_units', 'units')  

Where am I going wrong?

Answer 1

Use migrations.AlterField it will do all 4 steps in one.