fkInternalCalc和fkCalculated有何区别?

fkInternalCalc和fkCalculated有何区别?
能否举一个用到fkInternalCalc代码的例子?

 

fkInternalCalc是内部计算字段然后存进数据集的
fkCalculated只做零时计算用的

fkCalculated Field is calculated in an OnCalcFields event handler

fkInternalCalc Field is calculated but values are stored in the dataset.