SQLAlchemy

we must first import the necessary libraries, connect to db, and create a session to interface with the database:

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from database_setup import Base, Restaurant, MenuItem

engine = create_engine('sqlite:///restaurantMenu.db')
Base.metadata.bind=engine
DBSession = sessionmaker(bind = engine)
session = DBSession()

Create

myFirstRestaurant = Restaurant(name = "Pizza Palace")
session.add(myFirstRestaurant)
sesssion.commit()

cheesepizza = menuItem(name="Cheese Pizza", description = "Made with all natural ingredients and fresh mozzarella", course="Entree", price="$8.99", restaurant=myFirstRestaurant)
session.add(cheesepizza)
session.commit()

firstResult = session.query(Restaurant).first()
firstResult.name

items = session.query(MenuItem).all()
for item in items:
    print item.name

Update
In order to update and existing entry in our database, we must execute the following commands:
Find Entry
Reset value(s)
Add to session
Execute session.commit()

veggieBurgers = session.query(MenuItem).filter_by(name= 'Veggie Burger')
for veggieBurger in veggieBurgers:
    print veggieBurger.id
    print veggieBurger.price
    print veggieBurger.restaurant.name
    print "\n"

UrbanVeggieBurger = session.query(MenuItem).filter_by(id=8).one()
UrbanVeggieBurger.price = '$2.99'
session.add(UrbanVeggieBurger)
session.commit()

Delete
To delete an item from our database we must follow the following steps:
Find the entry
Session.delete(Entry)
Session.commit()

spinach = session.query(MenuItem).filter_by(name = 'Spinach Ice Cream').one()
session.delete(spinach)
session.commit()