Each employee may have various degrees from different dates.
How correctly to to build a table so that same employee will not get already existing degree?
Do you have a list of "Degrees" that you can choose from? if so, I'd have a drop down on it. If not, you should be able to check the DegDate and make sure they don't add two degrees for the same date.
Do you have a list of "Degrees" that you can choose from? if so, I'd have a drop down on it. If not, you should be able to check the DegDate and make sure they don't add two degrees for the same date.
The data is added to that table from the from, so drop down may be required on the form.Still the question is same "how I make sure" not to add two same degrees for the same employee?
Is it something that should be configured in Index propeety?
A unique index on Employee and date would prevent you from having two degrees issued the same date.
If you use a list of degrees, you can Join it to your table of degrees and exclude all where there is record for this employee. This means your users won't see it in the drop down list.