How to order child records by parent column using flask-sqlalchemy?

Question

class Parent(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    role_id = db.Column(db.Integer, db.ForeignKey('role.id')
    name = db.Column(db.String())
    children = db.relationship('Child', backref='parent')

class Child(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    parent_id = db.Column(db.Integer, db.ForeignKey('parent.id')
    name = db.Column(db.String())

I am trying to order child records by parent role_id:

child_recs = Child.query.order_by(?).all()

I tried by placing order_by attribute in db.relationship(), but it's not working.

children = db.relationship('Child', backref='parent', order_by='Parent.role_id')

Answer 1

I got the required results with the help of sorted():

child_recs = Child.query.all()
ordered_child_recs = sorted(child_recs, key=lambda rec: rec.parent.role_id)