Note: the query optimizer considers using a functional index when the index expression is used in a relational expression or as an argument to one of the operator class functions.
注意：当索引表达式被用于关系表达式，或作为某个操作符类函数的参数时，查询优化器将考虑使用函数索引。
2
All cranes will be equipped with a functional weight indicator on the main hoist and a boom Angle indicator, both visible by the operator.
所有的起重机都应当有主钩的起重能力指示器和扒杆角度指示器，并且起重机司机要看得见。
3
The functional design of each unit allows it to be equipped with a control panel using a programmable logic controller with an operator interface for a highly user-friendly operation.