Data validation(數據驗證) Programmer foresee possible errors and detect them and probably correct them Presence check- this field must be filled a Range check -Data exceed a limit? Type check -Data type match or not? a Consistency check-Strange data appear Control total -total no of record correct?Data validation (數據驗證) ◼ Programmer foresee possible errors and detect them and probably correct them ◼ Presence check - This field must be filled? ◼ Range check - Data exceed a limit? ◼ Type check - Data type match or not? ◼ Consistency check - Strange data appear? ◼ Control total - total no. of record correct?