Product option data of order.

Column	Type	Constraint	Description
shop	TEXT	PRIMARY KEY	Shop ID. (shop.username)
order_id	INTEGER		Order id. (order.id)
index	INTEGER		Index of products. (order_product.index)
option_id	INTEGER		Option ID. (option.id)
charge	INTEGER	NOT NULL	Option charge at when it was ordered. (option.charge)
quantity	INTEGER	NOT NULL	Quantity.

CREATE TABLE order_product_option(
shop       TEXT,
order_id   INTEGER,
index      INTEGER,
option_id  INTEGER,
charge     INTEGER  NOT NULL,
quantity   INTEGER  NOT NULL,
PRIMARY KEY(shop, order_id, index, option_id)
);