DATA QUALITY ASSERTIONS AND BUSINESS RULES
In this chapter, we explore the formal way to describe what we expect to see in terms of data quality. Through the definition of data quality rules, we can derive a means to both assess the current state of and measure the progress in improvement of the data’s quality.
Remember this basic principle: For any rule, given a set of data items and a data quality rule base, the data set can always be grouped into (1) items that conform to the rule and (2) items that do not conform to the rule. We will see more about this principle in Chapter 13 when we look at the automated discovery of data quality rules and in Chapter 17, where we explore the transformation of these rules into implementable objects.