Opened 7 years ago

Last modified 7 years ago

#28563 closed New feature

Allow parent relations to specify the related_name of a class property — at Initial Version

Reported by: Samuel Spencer Owned by: nobody
Component: Uncategorized Version: 1.11
Severity: Normal Keywords:
Cc: Triage Stage: Unreviewed
Has patch: no Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: yes UI/UX: no

Description

I can't come up with an appropriate example, so I'll use a cut back version of actual code. I'm trying to implement an ISO standard, and am using a concrete base class, with a number of relations between objects, as shown below. Unfortunately, the names of these objects and relations are defined by the spec and can't be changed without a lot of hassle.

class Metadata(models.Model):
    name = models.CharField(max_length=255)

class Property(Metadata):
    pass

class ObjectClass(Metadata):
    pass

class DataElementConcept(Metadata):
    object_class = models.ForeignKey(ObjectClass)
    property= models.ForeignKey(Property)

However, the system checker has a problem with this:

SystemCheckError: System check identified some issues:

ERRORS:
aristotle_mdr.DataElementConcept.property: (models.E006) The field 'property' clashes with the field 'property' from model 'aristotle_mdr._concept'.

What appears to happen is that DataElementConcept.property (a relation between two pieces of metadata) is clashing with MetadataItem.property (a relation from parent class to child class).

Since a parent-child relationship using inheritance is just a OneToOneField thats made by django.db.models.base.ModelBase it'd be nice to be able to add some details to a classes Meta field to change the related_name of the generated field, for example:

class Metadata(models.Model):
    name = models.CharField(max_length=255)

class Property(Metadata):
    class Meta:
        parent_related_name = "property_subclass"

and the ModelBase coude would be similar to:

                    field = OneToOneField(
                        base,
                        on_delete=CASCADE,
                        name=attr_name,
                        auto_created=True,
                        parent_link=True,
                        related_name=base._meta.parent_related_name
                    )

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