Decision-making questions such as those above pose new requirements on DBMSs. This chapter presents the technology and management of data warehouses to satisfy the requirements of decision support. Data warehouse technology complements and extends relational database technology beyond online transaction processing and simple query capabilities such as the GROUP BY clause in SQL. In this chapter, you will initially learn about the unique requirements for data warehouse processing as opposed to the transaction processing requirements discussed in Chapter 15. Then you will learn about the multidimensional data model and its implementation in relational databases with a special emphasis on the data warehousing features in Oracle 10g. You will learn new data modeling and query formulation skills that complement the data modeling material in Part 3 and the query formulation material in Parts 2 and 5. Finally, you will learn about maintaining a data warehouse, an important process managed by data warehouse administrators.