I am having a table T(ID, Headline, ...) where I would like to allow a Headline only to show up for a given ID (i.e. ID and Headline combined should be unique). Example
2, Headline3 << Not permitted, Headline3 already exists for ID=2
I could, of course, join T with itself, and check if List(T.ID) contains a specific "headline" already and then reject it. However, is there an easier way to do this?
Thanks of your help,