Chapter 2 laid down the basics of set theory. This fourth chapter will build on those basics and introduce some more set-theory concepts that will be used in Part 2 of this book as tools to define a database design formally—including all constraint specifications.

In the section “Binary Relations,” we’ll revisit ordered pairs and the Cartesian product to introduce the concept of a binary relation between two sets. As you’ll see, such a binary relation is in fact a subset of the Cartesian product of two sets.

The section “Functions” then introduces the important concept of a function. A function is a special kind of binary relation—one that conforms ...

Get Applied Mathematics for Database Professionals now with the O’Reilly learning platform.

O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.