Hi,
I'm trying to write a piece of code that would fetch the first event
belonging to an entity, when there might be many events associated:
class Entity(Model):
id = db.Column(db.Integer, primary_key=True)
events = db.relationship('Event', backref=backref('entity'))
class Event(Model):
id = db.Column(db.Integer, primary_key=True)
timestamp = db.Column(db.Float, primary_key=True)
entity_id = db.Column(db.ForeignKey(Entity.id))
I'm basically looking to implement something along the lines of this query:
SELECT entity.*,
event.id
FROM entity
OUTER JOIN event
ON event.id =
(
SELECT TOP 1 id
FROM event e
WHERE e.entity_id = entity.id
ORDER BY timestamp
)
But I have no idea how to achieve this with SQLAlchemy's ORM. I tried
playing with column_property for a bit, but couldn't wrap my head around it.
If anybody can provide any leads or explanations on how to do this I would
be most grateful.
Thanks in advance
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