class Match(Entity):
id = field.PrimaryKey(storetype.Integer(), name='match_id')
player_fk = rel.ManyToMany('Footballer', name='player')
class Footballer(Player):
name = field.Column(storetype.Text(max_length=80))
match_fk = rel.ManyToMany('Match', name='match')
class Author(Entity): # multiple many to many relation
id = field.PrimaryKey(storetype.Integer(), name='id')
name = field.Column(storetype.Text(max_length=30), name='name')
book_fk = rel.ManyToMany('Book', name='book_fk')
poem_fk = rel.ManyToMany('Poem')
class Poem(Entity): # multiple many to many relation
id = field.PrimaryKey(storetype.Integer(), name='id')
title = field.Column(storetype.Text(max_length=30), name='title')
author_fk = rel.ManyToMany('Author', name='author_fk')
class Actor(Entity): # many to many relation
id = field.PrimaryKey(storetype.Integer(), name='id')
name = field.Column(storetype.Text(max_length=30), name='name')
film_fk = rel.ManyToMany('Film', name='film_fk')