Hi,
I have a table that contains, among other columns, 4 columns that contain the same type of data, call them Chip1, Chip2, Chip3, Chip4. I want to create an Index that will check that the same entry cannot appear more than once in any row of any of the columns.
So, if Chip1 = ABC then ABC can only appear once in Chip1 and not at all in Chip2, 3 or 4. It would be better to do this as a one-to-many to another table but unfortunately the structure exists already. Is there a way of setting up a constraint that will prevent duplicates?
Thanks