A more complete example: from sqlalchemy import * from sqlalchemy.orm import * from sqlalchemy.ext.declarative import *
Base = declarative_base() class Item(Base): __tablename__ = 'item' id = Column(Integer, primary_key=True) type = Column(String) __mapper_args__ = { 'polymorphic_on': type, 'with_polymorphic': '*' } class Food(Item): calories = Column(Integer) __mapper_args__ = { 'polymorphic_identity': 'food' } class Book(Item): pages = Column(Integer) __mapper_args__ = { 'polymorphic_identity': 'book' } class Toy(Item): rating = Column(Integer) __mapper_args__ = { 'polymorphic_identity': 'toy' } class Basket(Item): pieces = relationship('BasketPiece', primaryjoin='Basket.id == BasketPiece.basket_id',) __mapper_args__ = { 'polymorphic_identity': 'basket' } class BasketPiece(Base): __tablename__ = 'basket_piece' basket_id = Column(None, ForeignKey(Basket.id), primary_key=True) piece_id = Column(None, ForeignKey(Item.id), primary_key=True) quantity = Column(Integer) piece = relationship(Item, foreign_keys=piece_id) if __name__ == '__main__': e = create_engine('sqlite:///poly_self_ref.db', echo=True) Base.metadata.create_all(e) s = Session(sessionmaker(e)) Piece = aliased(Item) s.query(Item) \ .outerjoin(BasketPiece, BasketPiece.basket_id == Item.id) \ .outerjoin(Piece, Piece.id == BasketPiece.piece_id) \ .filter(or_(Food.calories > 100, Book.pages < 500, Piece.calories > 100, Piece.pages < 500)) \ .all() -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at https://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.