How to build many-to-many relations using SQLAlchemy: a good example

by

From the comments I see you’ve found the answer. But the SQLAlchemy documentation is quite overwhelming for a ‘new user’ and I was struggling with the same question. So for future reference:

ItemDetail = Table('ItemDetail',
    Column('id', Integer, primary_key=True),
    Column('itemId', Integer, ForeignKey('Item.id')),
    Column('detailId', Integer, ForeignKey('Detail.id')),
    Column('endDate', Date))

class Item(Base):
    __tablename__ = 'Item'
    id = Column(Integer, primary_key=True)
    name = Column(String(255))
    description = Column(Text)
    details = relationship('Detail', secondary=ItemDetail, backref="Item")

class Detail(Base):
    __tablename__ = 'Detail'
    id = Column(Integer, primary_key=True)
    name = Column(String)
    value = Column(String)
    items = relationship('Item', secondary=ItemDetail, backref="Detail")

Leave a Comment