The problem is with the field clashes. Consider the following
from django.db import models
class TimeStampedModel(models.Model):
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(auto_now=True)
class Meta:
abstract = True
class Member(TimeStampedModel):
member_id = models.CharField(max_length=255)
class EliteMember(Member, TimeStampedModel):
additional_elite_data = models.TextField()
This results in the following system check error.
django.core.management.base.SystemCheckError: SystemCheckError: System
check identified some issues:
ERRORS:
myapp.EliteMember.created_at: (models.E006) The field 'created_at' clashes
with the field 'created_at' from model 'myapp.member'.
myapp.EliteMember.updated_at: (models.E006) The field 'updated_at' clashes
with the field 'updated_at' from model 'myapp.member'.
System check identified 2 issues (0 silenced).
As I mentioned earlier, if EliteMember would not inherit from
TimeStampedModel, EliteMember would not have the 'created_at' and
'updated_at' columns. And I do need that even on the inherited tables. So
this would require special handling in ModelBase and perhaps while
executing the queries against the tables.
On Wednesday, September 16, 2015 at 9:36:24 AM UTC-4, Christian Schmitt
wrote:
>
> I also think that this won't need to be in core since a Model Subclass
> works. We use this in our Application since we can't hard delete stuff so
> we overwritten the Model Field and the manager that all tables contain a
> date_deleted field which will be set when calling delete() objects.delete().
> And the Code was really simple, just create a class that extends
> models.Model and specifiy it abstract = True and then you can inherit from
> it in every of your models.
>
> 2015-09-16 13:13 GMT+02:00 Florian Apolloner <[email protected]
> <javascript:>>:
>
>> Settings.py is definitely not the way to go. As for Meta options: Feel
>> free, just do it via your own Model subclass, there is no need for this to
>> be in core imo.
>>
>> On Wednesday, September 16, 2015 at 7:44:17 AM UTC+2, Aron Podrigal wrote:
>>>
>>> Hi,
>>>
>>> I'd like to propose a created_at / modified_at auto field to models so
>>> that one can just turn this functionality on by a setting in settings.py or
>>> within the models Meta settings.
>>> I want these fields on both of the OneToOne related models when using
>>> concrete inheritance, thus using a TimeStampedBaseModel abstract model
>>> would cause these fields to clash. The reason I need created_at /
>>> updated_at on every table because Django is not the only app using the
>>> database I have other services sharing the same database. I assume having
>>> created_at updated_at fields on tables to be very common. I can imagine
>>> django creating those fields to all tables implicitly while handling those
>>> field collisions properly (eg. When accessing model.created_at on a
>>> derived class it will return the value of that model.
>>> model.base_model.created_at would give access to its base model).
>>>
>>> What are your thoughts?
>>>
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