From the first two chapters you should have gained a pretty good understanding of what tuples and relations are, at least from an informal point of view. Now I want to define those concepts more precisely, and I want to explore some of the consequences of those precise definitions. Perhaps I should warn you that the definitions can look a little daunting, but that's not unusual with formal definitions; the tuple and relation concepts themselves are quite straightforward, once you've struggled through the formalism, and you should be ready to do that by now because the terminology, at least, should be reasonably familiar to you. |