How can I make sure that duplicate data does not insert while updating

Question

Hi all I am using MYSQL database. My table is as follows

EmpID	FirstName	LastName	Middle
1001	Chaitanya	V	P

As per my requirement I would like to keep track the changes of employee details in the table when he tries to edit and update the data.

This data I will show in a gridview, not when user edits and update the data I would like to update the data only if changes are there. Means if he edits FirstName to Chaitu or LastName to D or Middle to Q or some other then only I would like to update the data.

If he tries to update it with the same data I don't want to update the record