One of the most important promises of the relational data model has been that it frees the decision maker, the manager, from the necessity of resorting to an intermediary, the programmer, in retrieving information from the organization’s database in response to unanticipated needs. That promise is founded on the availability of very high-level relational query languages such as SQL. Unfortunately, the current specification of the SQL standard fails to support users adequately in formulating complex queries involving set comparison that tend to arise in on-line analytical processing (OLAP) situations. As pointed out by Rao et al. (1996): “SQL’s syntax is too restricted to express quantified queries. While SQL allows subqueries to form sets, the relationships that can be expressed over sets are limited, and must be written in awkward and complicated ways.” This chapter presents a systematic approach for teaching users how to formulate in SQL complex set comparison queries encountered in ad-hoc decision-making scenarios.
Complete Chapter List
John A. Hoxmeier
Coral Calero, Mario Piattini, Marcela Genero
Anirban Bhaumik, Deepti Dixit, Roberto Galnares, Aparna Krishna, Michael Bieber, Vincent Oria, Firas Alljalad
M. Mehdi Owrang O.
Ladjel Bellatreche, Kamalakar Karlapalem, Mukesh Mohania
Manoj K. Singh, Mahesh S. Raisinghani
Esperenza Marcos, Paloma Caceres
Laura C. Rivero, Jorge H. Doorn, Viviana E. Ferraggine
Cheryl L. Dunn, Severin V. Grabiski
Eduardo Fernandez-Medina Paton, Mario G. Piattini
David J. Paper, James A. Rodger, Parag C. Pendharkar