In our example, the requirement that the relationship between a Sales Order and a Shipping Method is optional only if Special Instructions have been indicated is one such constraint.
In our example, the requirement that the relationship between a Sales Order and a Shipping Method is optional only if Special Instructions have been indicated is one such constraint.
在我们的例子里边，销售订单和运送方式之间的关系是可选的，有一条约束，就当有特定的说明，它们之间存在关系。