In the previous chapter, we have given a broad-brush state of the practice in data warehousing. In this chapter, we look again at the issues of data integration, multidimensional aggregation, query optimization, and data warehouse refreshment, focusing, however, on problems rather than solutions. Each of the topics we address is covered in the following chapters. We give special attention to data
... [Show full abstract] warehouse quality management, an issue that is the backbone of all the chapters of the book. Moreover, we briefly review some larger research projects that have addressed more than one of the issues and will therefore be cited in several places throughout the book. Finally, we take a critical overall look at this work and introduce the DWQ conceptual framework which takes the business perspective of data warehousing into account as well as the so far dominant technical aspects.