purchase order quantity

In other words, a purchase order containing a line item with a four-digit number in the Quantity element would be considered invalid.

换句话说，购买订单中的条目如果Quantity元素是四位数字，则认为是无效的。

Suppose you want to reuse the example above and add another operation that updates the product inventory, decreasing the product quantity for each item in the purchase order.

假设您想重用上面的例子，并加上一个更新产品库存，即减去购物订单中每项产品的产品数量的操作。

A join is performed inside the XQuery to show the name of each product, since the purchase order only stores product id, price, and quantity.

在XQuery内执行联接以显示每个产品的名称，因为采购订单仅存储产品ID、价格和数量。