more-inserts.py

# coding=utf-8

# 1 - imports
from datetime import date

from actor import Actor
from base import Session, engine, Base
from movie import Movie

# 2 - generate database schema
Base.metadata.create_all(engine)

# 3 - create a new session
session = Session()

# 4 - fetch a movie
bourne_identity = session.query(Movie) \
    .filter(Movie.title == 'The Bourne Identity') \
    .first()

print(f'Just fetched the {bourne_identity.title} movie.')

# 5 - add a new actor to it
franka_potente = Actor("Franka Potente", date(1974, 7, 22))
session.add(franka_potente)

# 6 - commit and close session
session.commit()
session.close()

# 7 - list all actors
actors = session.query(Actor).all()

print('### All actors:')
for actor in actors:
    print(actor.name)
print('')

This example only adds a new actor but doesn't attach her to "The Bourne Identity". Step #4 isn't needed at all. To attach her to the movie I
removed the add

session.add(franka_potente)

and then append her to the existing list of actors like this

bourne_identity.actors += [franka_potente]

Thanks for the tutorial!