Type Inheritance and Relational Theory

Footnotes

Preface

¹ In my defense here, I’m tempted to invoke what elsewhere I’ve called The Principle of Incoherence. To quote from my book The New Relational Database Dictionary (O’Reilly, 2016), The Principle of Incoherence (referred to by some, a little unkindly, as The Incoherent Principle) is “[a] principle, sometimes invoked in defense of an attempt (successful or otherwise) at criticizing some technical proposal or position, to the effect that it’s hard to criticize something coherently if what’s being criticized is itself not very coherent in the first place—a state of affairs that goes some way toward explaining why such criticisms can often be longer than what’s being criticized.”

Chapter 1: Background

¹ Use of the first person plural here, and indeed throughout this book, is intended to refer jointly to Darwen and myself unless the context demands otherwise.

² I’m being sloppy here: I shouldn’t really be talking in terms of types, as such, having subsets (only sets have subsets). In other words, the phrase “subset of T” should really be “subset of the set of values constituting T.” In the interest of brevity, however, I’ll continue to use this sloppy mode of speaking until further notice.

³ Some might dispute this claim.

⁴ I’ll have a lot more to say about the programmers and employees example, and others like it, in Chapter 21.

⁵ Specifically, in ACM SIGMOD Record 24, No. 1 (March 1995). However, an informal description of what it contained (“Introducing ... The Third ...