To add the join attribute to the Trip table and perform a connection with the stop_names table through the relationship on the sid column, we can use the relationship property. Here is the updated code:
python
from sqlalchemy.orm import relationship
# Definition of the model for the trips table
class Trip(Base):
__tablename__ = 'trips'
route_id = Column(String(255))
trip_id_1 = Column(Integer, primary_key=True)
trip_id_2 = Column(Integer, primary_key=True)
trip_id_3 = Column(Integer, primary_key=True)
direction_id = Column(Integer)
sid = Column(Integer, ForeignKey('stops.sid'))
# Adding the join attribute
stop_name = relationship("StopName", primaryjoin='Trip.sid == StopName.sid', uselist=False)
In this update, we added the stop_name attribute to the Trip class, which creates a relationship between the Trip and StopName tables using the sid key. Setting uselist=False ensures that the stop_name attribute will be a one-to-one relationship (i.e., one Trip record will correspond to one record in the StopName table).
However, it seems you encountered an error: AttributeError: type object 'Trip' has no attribute 'join'
python
selectable_query = select([Trip.sid, StopName.stop_name], from_obj=Trip.join(StopName, Trip.sid == StopName.sid).where(Trip.route_id.in_(route_ids), distinct=True))
It is important to understand that first, the route_id should be searched in the routes table, with only one row returned for each route_id, a total number of rows, which will be set to a test chunksize of 10, later chunksize 1000. So during the test, 10 rows and 10 different route_ids should be returned, then a left join should be performed... select stop_name from stop_names where it is possible that the resulting city names will be repeated. So I will have 10 different routes for 10 different trips (different bus lines) where the stop name will be for example "Ostrava, Bus Station" (10 identical results in the final output) must be allowed.
I understand that you need to execute a combination of select and join with the distinct condition to obtain unique combinations from the Trip and StopName tables based on route_id. Here is the updated code you can use:
python
from sqlalchemy import distinct
# Definition of the model for the trips table
class Trip(Base):
__tablename__ = 'trips'
route_id = Column(String(255))
trip_id_1 = Column(Integer, primary_key=True)
trip_id_2 = Column(Integer, primary_key=True)
trip_id_3 = Column(Integer, primary_key=True)
direction_id = Column(Integer)
sid = Column(Integer, ForeignKey('stops.sid'))
# Adding the join attribute
stop_name = relationship("StopName", primaryjoin='Trip.sid == StopName.sid', uselist=False)
# Creating a query with a combination of select, join, and distinct
selectable_query = select([Trip.route_id, StopName.stop_name]).select_from(Trip).join(StopName, Trip.sid == StopName.sid).where(Trip.route_id.in_(route_ids)).distinct()
This code creates a query with a combination of select and join, where the results are filtered by route_id and are also unique due to the use of distinct(). I hope this resolves your issue.
PLEASE NOTE: THIS CODE CAN BE COMPLETLY WRONG, IT'S LLM GENERATED.
