Overview

Having completed an analysis of individual column properties, the next step is to look at structure constraints that are, or should be, defined over the data. This may reveal additional problems in the data.

There are two issues to look for in structure analysis. One is to find violations to the rules that should apply. This points to inaccurate data. The other is to determine and document the structure rules of the metadata. This can be extremely valuable when moving data, mapping it to other structures, or merging it with other data.

Structure rules are often ignored when looking at data. This can have serious consequences when trying to extract the data for use in other data structures. The primary reason for ignoring them is that the analyst is not familiar with the basic concepts of database architecture. This makes structure analysis difficult. It is important that this step be performed by someone who has the right background. Any analyst can learn the basic concepts and should take the time to do so.

9.1 Definitions

It is not the intention of this book to provide a thorough education on database structure rules. The definitions provided here are brief and intended only to clarify how terms are being used in this chapter. Definitions of the terms used in this section are needed for the same reason as the previous chapter: these terms tend to be used in different ways by different authors and database systems. Defining how they are used here may head off some confusion.

The rule discussions in this book assume that data is being represented in a...