How to get a field from from last row of an change log table in SQLAlchemy - python-3.x

Question

I have the follow example. When calling Order.next I would expect to return a single order in the with the status NEW. However I am getting Orders in other OrderStatus.
If it matters this is using SQLite backend.
class OrderStatus(enum.Enum):
NEW = 0
MAKING = 1
MADE = 2
COLLECTED = 3
class Order(Base):
__tablename__ = 'orders'
id = Column(Integer, primary_key=True)
updates = relationship("OrderUpdate", order_by = "OrderUpdate.position", collection_class=ordering_list('position'))
#hybrid_method
def next(self):
order = Order.query \
.filter(Order.status in [OrderStatus.NEW]) \
.order_by(Order.id) \
.first()
return order
#hybrid_property
def status(self):
update = OrderUpdate \
.query.filter_by(order_id = self.id) \
.order_by(OrderUpdate.id.desc()) \
.first()
if update is None:
return None
return update.status
class OrderUpdate(Base):
__tablename__ = 'order_updates'
id = Column(Integer, primary_key=True)
position = Column(Integer)
status = Column('status', Enum(OrderStatus))
comment = Column(String)
order_id = Column(Integer, ForeignKey("orders.id"))
order = relationship("Order", back_populates="updates")

Answer 1

I didn't check, but I think the problem with line:
.filter(Order.status in [OrderStatus.NEW])
If you need to use in condition you need to use sqlalchemy in_(). So in your case it should be like this: Order.status.in_([1, 2]). Also you can do it without in_():
Order.query.filter_by(Order.status=0).order_by(Order.id).first()
Note! About Enum. This is not about Flask or Flask-SqlAlchemy. Just for you information.
# Python 3.6.1
class OrderStatus(enum.Enum):
NEW = 0
0 in [OrderStatus.NEW] # False
0 in [OrderStatus.NEW.value] # True
val = OrderStatus(0)
val in [OrderStatus.NEW] # True
Hope this helps.