Trying to configure a set of relationships to all be joined loaded and the particular relationship structure doesn’t seem to want to join. I have a one-to-many relationship where the many is the child in joined table inheritance. The foreign key to my source table is on the polymorphic child table. But, however I configure the relationship it does a subquery instead of a joined load on the parent class.
Built a test application as a demonstration. What I want is to have the script below function the same way but, the query at the end outputs a joinedload for PolyParent instead of a subquery. from sqlalchemy import Column, ForeignKey, Integer, Text, create_engine from sqlalchemy.ext.declarative import declarative_base from sqlalchemy.orm import relationship, sessionmaker Base = declarative_base() class PolyParent(Base): __tablename__ = "poly_parent" id = Column(Integer, primary_key=True) type = Column(Text) __mapper_args__ = {"polymorphic_identity": "poly_parent", "polymorphic_on": type} class PolyChild(PolyParent): __tablename__ = "poly_child" id = Column(Integer, ForeignKey("poly_parent.id"), primary_key=True) parent_id = Column(Integer, ForeignKey("source.id")) __mapper_args__ = {"polymorphic_identity": "poly_child"} class Source(Base): __tablename__ = "source" id = Column(Integer, primary_key=True) children = relationship(PolyChild) engine = create_engine("sqlite://") session = sessionmaker(bind=engine)() Base.metadata.create_all(bind=engine) print(session.query(Source).join(Source.children)) -- 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/70b48614-d1c0-42f4-8792-ed96f181915dn%40googlegroups.com.