Django formset save() writes new object on database?-CodePudding

So I have MyModel:

class MyModel(models.Model):
    name = models.CharField(_('Name'), max_length=80, unique=True)
    ...

    def save(self, *args, **kwargs):
        if MyModel.objects.count() >= 5:
            raise ValidationError("Can not have more than 5 MyModels!")
        super().save(*args, **kwargs)  # Call the "real" save() method.

There are already 5 objects from MyModel on the database. I have a page where I can edit them all at the same time with a formset. When I change one or more of them, I will get the Validation Error "Can not have more than 5 MyModels!". Why is this happenning? I tought the formset was supposed to edit the existing objects, but it appears to be writing a new one and deleting the old one.

What is really happening when I do a formset.save() on the database? Do I have to remove the save() method?

CodePudding user response：

The save method inside the Model is called regardless you are creating or editing. Although you can distinguish between them by checking if the object has a primary key, like this:

if not self.pk and MyModel.objects.count() >= 5:

If you want more sophisticated control over validation, I suggest putting them in the forms. Specially if you want to limit the number of formset, you can check this documentation.