I'm trying to do something a little unusual, I'm open to alternative ideas for how to accomplish this as well but I think I need a 3 column mixer table with 3 foreign keys.
Right now I have many to many relationships between 3 tables, e.g. a m2m b b mbm c however, I really something like (a_id, b_id, c_id) (again, could be a different way that i'm totally open to using) because only some Bs and Cs will be valid for an A, and so forth. i still need to be able to associate many to many with each other, but with a discriminator (where) on the third column like a.bs where c=some_value Is an association object capable of this or am I barking up the wrong tree? from sqlalchemy.ext.declarative import declarative_base from sqlalchemy import Integer, Column, ForeignKey from sqlalchemy.orm import relationship Base = declarative_base() class Association(Base): __tablename__ = 'association' a_id = Column(ForeignKey('a.id'), primary_key=True) b_id = Column(ForeignKey('b.id'), primary_key=True) c_id = Column(ForeignKey('c.id'), primary_key=True) parent = relationship("A", back_populates="children") child = relationship("B", back_populates="parents") #cousin = relationship("C", back_populates="relatives") ??? class A(Base): __tablename__ = 'a' id = Column(Integer, primary_key=True) children = relationship("Association", back_populates="parent") class B(Base): __tablename__ = 'b' id = Column(Integer, primary_key=True) parents = relationship("Association", back_populates="child") class C(Base): __tablename__ = 'c' id = Column(Integer, primary_key=True) # relatives = relationship("Association", back_populates="cousin") -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/e5861bb3-5da9-494e-bbf8-f9275df26dc5n%40googlegroups.com.