In other words, a purchaseorder 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。
2
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 purchaseorder.
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。
3
A join is performed inside the XQuery to show the name of each product, since the purchaseorder only stores product id, price, and quantity.