SQLAlchemy - model simple inheritance

Question

Is there anything wrong with inheritance in which child class is only used to present parent's values in a different way?

Example:

class Parent(db.Model):

    __tablename__ = u'parent'

    parent_entry_id = db.Column(db.Integer, primary_key=True)
    parent_entry_value = db.Column(db.BigInteger)

class Child(Parent):

   __tablename__ = u'child'

   @property
   def extra_value(self):
       return unicode(self.parent_entry_id) + unicode(self.parent_entry_value)

No new values will be added Child class, thus Joined Table, Single Table or Concrete Table Inheritance, as for me, is not needed.

Wayne Werner · Accepted Answer · 2016-02-25 15:52:40Z

1

If you're simply changing how you display the data from the class, I'm pretty sure you don't need a __tablename__.

Additionally, though I don't know your exact problem domain, I would simply just add the property on the original class. You could argue that you're adding some extra behavior to your original class, but that seems like a bit of a flimsy argument in this case.

answered Feb 25, 2016 at 15:52

Wayne Werner

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1 Comment

LAdas Over a year ago

Oh, yes - I've forgotten to remove __tablename__ from Child. It shouldn't be there. Except typo is this "simple" inheritance ok in this case?

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