Meta class inheritance with constraints

Using Django Using the ORM
1

Hi, everyone

I have a question.

I created a model with two classes: an abstract base class and a child class.
I want to use inheritance in the meta class and extend it in the child class.

class Person(models.Model):
    # ...
    class Meta:
        abstract = True
        constraints = [
            models.CheckConstraint(
                name="check_1",
                check=Q(...)
            )
            models.CheckConstraint(
                name="check_2",
                check=Q(...)
            )
        ]


class Student(Person):
    # ...
    class Meta(Person.Meta):
        pass

In this way, constraints are also available in the Student class. I would like to
add an additional constraint in the child class. That’s why the child
in the meta class I created a constraint “constraints = […]”.

class Student(Person):
    # ...
    class Meta(Person.Meta):
        constraints = [
            models.CheckConstraint(
                name="check_3",
                check=Q(...)
            )
        ]

However, this overrides the parent’s “constraints = […]” variable. This is how I tried it
bypass:

class Student(Person):
    # ...
    class Meta(Person.Meta):
        constraints = Person.Meta.constraints
        constraints += [
            models.CheckConstraint(
                name="check_3",
                check=Q(...)
            )
        ]

And that’s how all three restrictions work now.

My question is, is this method any good? Or should it be done differently?
Thank you all in advance for your help.

2

It works? Yes? It’s good.

Mechanically, there are many ways to do this. (e.g., Using the append method instead of +=.)

But overall, what you’re doing seems to me to be at least as good as any of the alternatives I can think of.

3

Thanks Ken

Since I didn’t see a description/instructions for this anywhere, I made this up.
I was just wondering how others have solved this.

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