unnecessary function的意思|示意

It is generally unnecessary to verify the isolation capacitance on a switch card, because the capacitance is a mechanical function and should not change over time.

由于电容属于一种机械性能，并且不应随时间发生变化，所有通常必须要验证开关卡上的隔离电容。

If you leave the unit powered-on for 20 minutes without performing any operation, the auto power off function will turn the power off automatically, avoiding unnecessary battery consumption.

如果您离开本单位已启动的20分钟不执行任何操作，自动关机功能会自动关闭电源，避免不必要的电池消耗。

Deterministic function calls can be extracted from the WHERE clause to avoid unnecessary table scan.

可以从WHERE子句中提取确定性函数调用，避免不必要的表扫描。