[Fixed]-In my models.py, one ForeignKey declaration does not require a default, but the other does? Why?

by

1đź‘Ť

âś…

You’re adding only a single new column called menu_category, right? The restaurant field does not give errors because it already exists.

Django gives you this error because you are adding a field that can’t be null to a table that already exists without a default value. You either need to allow nulls (so the created column values can be empty in rows that already exist) or specify a default value to fill the column with.

Django should be asking you if you want to provide a “one-off” default value just for the migation. If you have some “default” menu category that the FoodItem objects can have, then specify its id when django prompts you for a value.

Example prmopt:

$ python manage.py makemigrations 
You are trying to add a non-nullable field 'menu_category' to fooditem without a default;
we can't do that (the database needs something to populate existing rows).
Please select a fix:
 1) Provide a one-off default now (will be set on all existing rows)
 2) Quit, and let me add a default in models.py
Select an option: 1
Please enter the default value now, as valid Python
The datetime module is available, so you can do e.g. datetime.date.today()
>>> 1
Migrations for 'my_app':
  0002_fooditem_menu_category.py:
    - Add field menu_category to fooditem
👤Anonymous

Leave a comment