Chapter 6: Numeric Data

Chapter 6: Numeric Data

Overview

Numbers are even trickier than people think. Most people do not make a distinction between a number and a numeral in everyday conversation. A number is the abstraction represented by the numeral, which is a written symbol. Roman numerals, Chinese numerals, Mayan numerals, and hundreds of other systems have existed to represent numbers in a written form so that they could be recorded or manipulated.

The Hindu-Arabic numerals and place value notation have proven so useful that they have replaced all other systems today. Because Hindu-Arabic numerals are on every computer printer, are universally understood, and linguistically neutral, we use Hindu-Arabic numerals for many different purposes, and we are not always clear about the distinctions. The three uses for the numerals in a database are for cardinal numbers, ordinal numbers, and tag numbers.

6.1 Tag Numbers or Absolute Scales

A tag number or absolute scale is simply a list of names for the elements of a set. The advantage of using numbers instead of names is that a computer can store them more compactly, they are linguistically neutral, and there are simple rules for generating an unlimited number of such values. This is discussed in some detail in Chapter 12 , so we will not go into that concept here.

6.2 Cardinal Numbers

The usual definition of a cardinal number is something that represents a quantity or magnitude (0, 1, 2, 3, . . .), and it is what people mean most of the...

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