what you are seeing is somewhat backwards due to what might be a bug. in the
example you have, *both* calls to group.users should be raising, because this
object is already present in the identity map so your lazyload() option should
not affect this already-present Group object.
if you load the Group newly into a new Session, or session.close() the one you
have, then the lazyload() option is associated with the Group and it will lazy
load every time for the lifespan of that object.
I'm not sure yet why the lazyload() is somehow taking effect for the first
group.users in your example, though. it's not supposed to.
On Wed, Sep 25, 2019, at 1:07 PM, Marat Sharafutdinov wrote:
> from sqlalchemy import Column, ForeignKey, Integer, create_engine
> from sqlalchemy.ext.declarative import declarative_base
> from sqlalchemy.orm import lazyload, relationship, sessionmaker
>
> Base = declarative_base()
>
>
> class Group(Base):
> __tablename__ = 'groups'
>
> id = Column(Integer, primary_key=True)
>
> users = relationship('User', lazy='raise')
>
>
> class User(Base):
> __tablename__ = 'users'
>
> id = Column(Integer, primary_key=True)
> group_id = Column(Integer, ForeignKey('groups.id'))
>
>
> engine = create_engine('sqlite:///:memory:', echo=True)
> Base.metadata.create_all(engine)
>
> Session = sessionmaker(bind=engine)
> session = Session()
>
> group = Group()
> session.add(group)
> session.commit()
>
> group = session.query(Group).options(lazyload(Group.users)).first()
> print('SUCCESS', group.users)
> session.refresh(group)
> print('FAILURE', group.users)
>
> Is `session.expire(group)` is the only way to reload collections and related
> items?
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
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> To post example code, please provide an MCVE: Minimal, Complete, and
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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
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