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SQLAlchemy-OrderingItem provides an OrderingItem base for children of orderinglist relationships.

Project description

SQLAlchemy-OrderingItem provides an OrderingItem base for children of orderinglist relationships. Children of orderinglist relationships will exhibit more intuitive behavior when setting their parent attribute.


$ pip install sqlalchemy-orderingitem


from sqlalchemy_orderingitem import OrderingItem

from sqlalchemy import Column, ForeignKey, Integer, create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.ext.orderinglist import ordering_list
from sqlalchemy.orm import sessionmaker, relationship

# standard session creation
engine = create_engine('sqlite:///:memory:')
Session = sessionmaker(bind=engine)
session = Session()
Base = declarative_base()

class Parent(Base):
    __tablename__ = 'parent'
    id = Column(Integer, primary_key=True)

    # declare orderinglist relationships
    children = relationship(

# subclass OrderingItem for children of orderinglist relationships
class Child(OrderingItem, Base):
    __tablename__ = 'child'
    id = Column(Integer, primary_key=True)
    parent_id = Column(Integer, ForeignKey(''))
    index = Column(Integer)

# create database tables and instantiate parent and child
parent = Parent()
child = Child()
session.add_all([parent, child])

# example 1: setting a child's parent attribute to Parent object
# we expect the child's index to be 0
child.parent = parent

# example 2: setting a child's parent attribute to None
# we expect the child's index to be None
parent.children = [c]
child.parent = None



If Child did not subclass OrderingItem, we would observe the following unintuitive output:



  author = {Dillon Bowen},
  title = {SQLAlchemy-OrderingItem},
  url = {},
  date = {2020-06-05},


Users must cite this package in any publications which use it.

It is licensed with the MIT License.

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