Can key constraint application in Database be applied on a part of a single column?
we can apply the key constraint either to column level or table level, but
I want to know is there any possibility that a unique key be applied only on to a part of a single column?
I was asked this question by one of my friends, as far as i know there is no concept like that.
example there is a column named timestamp and value in that column is like 2014-06-23 01:02:03
so i want to apply unique key based on time only, ignoring the date.
is that possible?
So please help me know if there is any possibility.