One-to-one relationship as a boolean flag

[Pedro Werneck]

Let's say I have a table 'user', and for backwards compatibility reasons I have a single-column table named 'user_active' which is basically just a foreign key used as a boolean flag. I need my User model to have the 'active' field as a boolean mapped to that one-to-one relationship. So, I have something like this:

class User(db.Model):

    __tablename__ = 'user'

    user_id = db.Column(db.Integer, primary_key=True)

    # ... other fields

    active = relationship('UserActive', backref='user', uselist=False)

class UserActive(db.Model)

    __tablename__ = 'user_active'

    user_id = db.Column(db.Integer, db.ForeignKey('user.user_id')

Using the simple relationship like that returns either the UserActive instance, or None, which isn't ideal as True or False but works fine in any boolean context. My problem is assignment and querying. How can can I get it to work in a way that setting User.active = True creates the new UserActive instance, and querying for User.active == True works as a join, not a subquery?

[Mike Bayer]

why not make a @hybrid_property called "active", call the relationship _active, and then customize access completely?

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[Pedro Werneck]

I thought maybe there was a simpler way to do that, but the
hybrid_property works. Thanks.

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Pedro Werneck