To actually generate the tables, there are two methods that can be used. Table model classes have an internal __table__ method that has a create function, which can be used to create each table separately. There is also a drop function that can be called to drop a table.

In the script, we use try/except blocks to generate the tables. If an exception is incurred (that is, if the table already exists), the table is dropped and then created. Here is the State table creation statement as an example:

    # Generate the State table from the State class.
    # If it already exists, drop it and regenerate it
    try:
        State.__table__.create(engine)
    except:
        State.__table__.drop(engine)
        State.__table__.create(engine)

Alternatively, all database tables can be generated from the defined classes using the Base method metadata and its create_all function:

    Base.metadata.create_all(engine)