Missing 1 required positional argument: 'on_delete'?

Question

So: I'm trying to implement Django CMS to my Django website and I'm facing the "OneToOneField.init() missing 1 required positional argument: 'on_delete'" in my models.py from Django.

from django.db import models


class Word(models.Model):
    word_name = models.CharField(max_length=50)
    word_about = models.TextField()
    word_resources = models.URLField()

    def __str__(self):
        return self.word_name

    class Meta:
        db_table = 'words'


class Principle(models.Model):
    word = models.ForeignKey(Word, on_delete=models.CASCADE)
    principle_name = models.CharField(max_length=100)
    principle_description = models.TextField()

    class Meta:
        db_table = 'principles'


class CodeSnippet(models.Model):
    raw_code = models.TextField()

What I've tried:

this, this + chatgpt

so basically: word = models.OneToOneField(Word, on_delete=models.CASCADE), word = models.OneToOneField(Word, on_delete=models.CASCADE/PROTECT/DO_NOTHING/SET_DEFAULT)

Isn't setting `on_delete=models.CASCADE` not working for you? — adityanithariya, Aug 31 '23 at 09:39
Where is the `OneToOneFIeld` that is causing the problem? Your code fragment has a `ForeignKey`? — Willem Van Onsem, Aug 31 '23 at 09:40
@WillemVanOnsem Actually, question is unclear and need an edit. You should consider adding a [minimal reproducible example](https://stackoverflow.com/help/minimal-reproducible-example) — adityanithariya, Aug 31 '23 at 09:43
That is the error I'm getting whenever I want to `runserver` or `make migrations`. — biscuit_delicious, Aug 31 '23 at 09:44
that is the part of the code that has the problem. That is my `models.py` — biscuit_delicious, Aug 31 '23 at 09:45
Post complete code of your models.py, as code you've posted doesn't seem to be errorful — adityanithariya, Aug 31 '23 at 09:47
You can try deleting `migrations` and `__pycache__` folders, then run `makemigrations` again — adityanithariya, Aug 31 '23 at 09:49
That is my `models.py`'s full code. https://streamable.com/z25x31 for proof — biscuit_delicious, Aug 31 '23 at 09:56
Same error after I deleted the `migrations` and `__pycache__` folder. — biscuit_delicious, Aug 31 '23 at 10:03
your `djangocms-inherit` is outdated, that is the problem... — Willem Van Onsem, Aug 31 '23 at 10:05
I'm using `djangocms-inherit` version 0.2.2, also added in `requirements.txt` — biscuit_delicious, Aug 31 '23 at 10:11
@biscuit_delicious: well clearly that version (or perhaps the entire package), is not compatible with Django-2.0 and beyond... — Willem Van Onsem, Aug 31 '23 at 10:13
Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking. — Shawn, Sep 01 '23 at 06:50

score -1 · Answer 1 · edited Sep 02 '23 at 17:11

-1

No, you cannot use on_delete=models.CASCADE with a OneToOneField. The on_delete=models.CASCADE option is not allowed for OneToOneField fields because a OneToOneField represents a unique relationship where each record in the model points to at most one other record.

If you were to use CASCADE as the deletion behavior, it would essentially mean that deleting one record would cause the associated record to be deleted as well, resulting in potential data loss and referential integrity issues.

Instead you can use the models.SET_NULL, models.PROTECT, models.SET_DEFAULT with OneToOneField.
with Foreign key you can use models.CASCADE.

edited Sep 02 '23 at 17:11

Bihag Kashikar

1,009
1
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answered Aug 31 '23 at 12:44

Anjali Rana

9
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Was this answer generated by ChatGPT? It congestive obviously incorrect explanation, `OneToOneField(SomeModel, on_delete=models.CASCADE)` is perfectly legal, as can be seen in [first example from docs](https://docs.djangoproject.com/en/4.2/topics/db/examples/one_to_one/). I also can personally confirm that such definition works fine. The argument about data loss is just weird: you're the developer, and it's your decision whether related models should go away when the source is deleted. In many cases such behavior is desirable. – STerliakov Sep 02 '23 at 17:38

Missing 1 required positional argument: 'on_delete'?

1 Answers1