Python - Inherit from class which inherit Model

Question

Here is my problem: I try to create layer under

models.Model

My Model -

class MainModel(models.Model):
    @staticmethod
    def getIf(condition):
        results = __class__.objects.filter(condition)
        if results.count() > 0:
            return results.first()
        else:
            return None

And that's a model

class User(MainModel):
    id = models.AutoField(primary_key=True)
    name = models.CharField(max_length=256)
    date_create = models.DateTimeField(auto_now_add=True)
    date_last_login = models.DateTimeField(null=True)

But my project is crushed with error -

django.core.exceptions.FieldError: Local field 'id' in class 'User' clashes with field of the same name from base class 'MainModel'.

What am I doing wrong?

UPD: if you want to do like this, you need to use subclass Meta in your layer

class MainModel(models.Model):
    @staticmethod
    def getIf(condition:dict):
        results = __class__.objects.filter(condition)
        if results.count() > 0:
            return results.first()
        else:
            return None

    class Meta:
        abstract = True

Have you read the documentation on model inheritence?

ikkuh
– ikkuh

2017-08-28 12:49:48 +00:00
Commented Aug 28, 2017 at 12:49 — ikkuh
– ikkuh, Commented Aug 28, 2017 at 12:49
Use user_id in place of id.

0decimal0
– 0decimal0

2017-08-28 13:20:12 +00:00
Commented Aug 28, 2017 at 13:20 — 0decimal0
– 0decimal0, Commented Aug 28, 2017 at 13:20
not, of course, if I asks )) ok, I found what I lost

Maksim Zarechnyi
– Maksim Zarechnyi

2017-08-28 13:26:56 +00:00
Commented Aug 28, 2017 at 13:26 — Maksim Zarechnyi
– Maksim Zarechnyi, Commented Aug 28, 2017 at 13:26

Maksim Zarechnyi · Accepted Answer · 2017-08-29 09:07:05Z

3

Thanx, but I'm not trying to override fields, In my layer no one field is not defined. I found my answer, I just have to read documentation.

if you want to do like this, you need to use subclass Meta in your layer

class MainModel(models.Model):
    @staticmethod
    def getIf(condition:dict):
        results = __class__.objects.filter(condition)
        if results.count() > 0:
            return results.first()
        else:
            return None

    class Meta:
        abstract = True

answered Aug 29, 2017 at 9:07

Maksim Zarechnyi

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2 Comments

Daniel Roseman Over a year ago

Alternatively, you could make MainModel a mixin, that inherits from just object, and then your actual model can be class User(MainModel, models.Model).

Maksim Zarechnyi Over a year ago

yee, thanks :) it was one of my trying, but I want to understand as much as I can and had to understand how can I do exactly it )

user2021091 · Accepted Answer · 2017-08-28 13:30:36Z

1

Django adds a field id to all Models, you have to remove it.

Ok I understand your question better now, your answer is there:

In Django - Model Inheritance - Does it allow you to override a parent model's attribute?

Django already adds a field id to your parent model.

edited Aug 28, 2017 at 13:30

answered Aug 28, 2017 at 13:12

user2021091

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1 Comment

Maksim Zarechnyi Over a year ago

But if I create it directly in class, which inherit models.Model all is fine - field id successfully created in db

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