A variable of an enumerated type can hold values outside the range of declared values. 枚举类型的变量可以接受声明值范围之外的值。
Range locks are placed in the range of key values that match the search conditions of each statement executed in a transaction. 范围锁处于与事务中执行的每个语句的搜索条件相匹配的键值范围之内。
