from sqlalchemy import *
from sqlalchemy.orm import *

engine = create_engine('sqlite:///')
metadata = MetaData(engine)

# Tables
user_table = Table('user', metadata,
        Column('id', Integer, primary_key=True),
        Column('login', String(8), nullable=False, unique=True))

item_table = Table('item', metadata,
        Column('id', Integer, primary_key=True),
        Column('address', String(50), nullable=False, unique=True))

tag_table = Table('tag', metadata,
        Column('id', Integer, primary_key=True),
        Column('tag', String(50), nullable=False, unique=True))

user_tag_item_table = Table('user_tag_item', metadata,
        Column('id', Integer, primary_key=True),
        Column('user_id', Integer, ForeignKey('user.id')),
        Column('item_id', Integer, ForeignKey('item.id')),
        Column('tag_id', Integer, ForeignKey('tag.id')))

metadata.create_all()

Session = sessionmaker(bind=engine, autoflush=True, transactional=True)

# Objects
class User(object):
    def __init__(self, login):
        self.login = login

    def __repr__(self):
        return "User(%r)" % self.login

class Item(object):
    def __init__(self, address):
        self.address = address

    def __repr__(self):
        return "Item(%r)" % self.address

class Tag(object):
    def __init__(self, tag):
        self.tag = tag

    def __repr__(self):
        return "Tag(%r)" % self.tag

class UserTagItem(object):
    def __init__(self, user, tag, item):
        self.user = user.id
        self.tag = tag.id
        self.item = item.id

    def __repr__(self):
        return "UserTagItem(%r %r %r)" % (self.user, self.tag, self.item)

# Mappers ???