__tablename__ = 'user_email_map'

    __table_args__ = (

        Index('uem_email_idx', 'email'),

        UniqueConstraint('email'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'}

    )

    __mapper_args__ = {}

    email_id = Column("email_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)

    user_id = Column("user_id", Integer(), ForeignKey('users.user_id'), nullable=True, unique=None, default=None)

    _email = Column("email", String(255, convert_unicode=False, assert_unicode=None), nullable=True, unique=False, default=None)

    user = relationship('User', lazy='joined')

    @validates('_email')

    def validate_email(self, key, email):

        # check if this email is not main one

        main_email = Session().query(User).filter(User.email == email).scalar()

        if main_email is not None:

            raise AttributeError('email %s is present is user table' % email)

        return email

    @hybrid_property

    def email(self):