Hi everyone.
Recently I’ve decided to switch some models to multi-table inheritance relation. Some models having no FK / M2M relations already swapped and now I’m trying to find out an easy way to do the same for the models linked with ForeignKey.
As I know concrete inheritance enforce models reffering to parent FK rather having its own. So whenever last phase of migration applied (setting parent model as class inherited from) on existing model its id replaced with parent_ptr field and rest of the models refering to this model through FK relation loosing that link.
Let’s imagine I have a models:
class Member(models.Model):
pass
class Person_A(models.Model):
member_ptr = OneToOneField(parent_link=True, null=True, blank=True)
class Person_B(models.Model):
member_ptr = OneToOneField(parent_link=True, null=True, blank=True)
class Group(models.Model):
person_a = models.ForeingKey(Person_A)
person_b = models.ForeignKey(Person_B)
In this case Person_A and Person_B still have their id and Group relations are ok. However when I remove member_ptr and replacing models.Model with parent class Member concrete inheritance enforced but primary key will be changed what causes all FK links to fail.
I have some ideas how to preserve data adding some temporary fields to Group with FK link to Member model and make few more steps to transfer data but it fills like I’m missing some easier way.
Would appreciate any ideas.
Just to clear some questions : All Member instances required to link with Person_A and Person_B already created and populated with required data.