class User(DB.Model):
    __tablename__ = 'users'
    id = DB.Column(DB.Integer, primary_key=True)
    username = DB.Column(DB.String(64), index=True)
    password = DB.Column(DB.String(128))

__tablename__ = 'customer'
customer_id = DB.Column(DB.Integer, primary_key=True)
customer_name = DB.Column(DB.String, unique=True, index=True)

SQLALCHEMY_BINDS = {
    'customer1' = 'sqlite:////path/customer1.db',
    'customer2' = 'sqlite:////path/customer2.db',
    ...
}