In Django, using __init__() method of non-abstract parent model to record class name of child model
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Published on 2010-06-09T02:33:35Z
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2010/06/09
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django-models
In my Django project, I have a non-abstract parent model defined as follows:
class Parent(models.Model):
classType = models.CharField(editable=False,max_length=50)
and, say, two children models defined as follows:
class ChildA(Parent):
parent = models.OneToOneField(Parent,parent_link=True)
class ChildB(Parent):
parent = models.OneToOneField(Parent,parent_link=True)
Each time I create an instance of ChildA or of ChildB, I'd like the classType attribute to be set to the strings "ChildA" or "ChildB" respectively. What I have done is added an _ _ init_ _() method to Parent as follows:
class Parent(models.Model):
classType = models.CharField(editable=False,max_length=50)
def __init__(self,*args,**kwargs):
super(Parent,self).__init__(*args,**kwargs)
self.classType = self.__class__.__name__
Is there a better way to implement and achieve my desired result? One downside of this implementation is that when I have an instance of the Parent, say "parent", and I want to get the type of the child object linked with "parent", calling "parent.classType" gives me "Parent". In order to get the appropriate "ChildA" or "ChildB" value, I need to write a "_getClassType()" method to wrap a custom sql query.
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