Requirement Specification and Conceptual Modeling for Data Warehouses

IntroductIon Data warehouses (DWs) integrate data from different source systems in order to provide historical information that supports the decision-making process. The design of a DW is a complex and costly task since the inclusion of different data items in a DW depends on both users' needs and data availability in source systems. Currently, there is still a lack of a methodologi-cal framework that guides developers through the different stages of the DW design process. On the one hand, there are several proposals that informally describe the phases used for developing DWs based on the authors' experience in building On the other hand, the scientific community proposes a variety of approaches for developing DWs, discussed in the next section. Nevertheless, they either include features that are meant for the specific conceptual model used by the authors, or they are very complex. This situation has occurred since the need to build DW systems that fulfill user expectations was ahead of methodological and formal approaches for DW development, just like the one we had for operational databases. Specifically, the approaches for requirements specifications and conceptual modeling differ significantly because some of them rely mainly on user requirements, while others take into consideration the underlying operational databases instead of user needs. Such diversity of approaches may overwhelm designers who could find it difficult to identify the one approach that better fits to particularities of a DW project. In this chapter we refer to requirements specification and conceptual modeling phases for DW design. Our proposal unifies the already existing approaches by giving an overall perspective of different alternatives available to designers when developing a DW.