[SQLAlchemy]複合キーの作成

class Rating(db.Model):
    __tablename__ = 'rating'
    #__table_args__ = db.ForeignKeyConstraint([user_id, book_id], [Users.id, Books.id])
    __table_args__ = (db.PrimaryKeyConstraint('user_id', 'book_id', name = 'user_rating_uc'), )

    def __init__(self, user_id, book_id, point, description):
        self.user_id = user_id
        self.book_id = book_id
        self.point = point
        self.description = description

    cur = datetime.datetime.now()

    user_id = db.Column(db.Integer, db.ForeignKey('users.id'), nullable=False)
    book_id = db.Column(db.Integer, db.ForeignKey('books.id'), nullable=False)
    point = db.Column(db.Integer, nullable=False)
    created_date = db.Column(db.DateTime, nullable=False, default=cur)
    description = db.Column(db.String(250), nullable=False)