1. Introduction
Data warehousing is a collection of decision support technologies, amied at enabling the knowledge worker (executive, manager, analyst) to make better and faster decisions. The past three years have seen explosive growth, both in the number of products and services offered, and in the adoption of these technologies by industry. According to the META Group, the data warehousing market, including hardware, database software, and tools, is projected to grow from $2 billion in 1995 to $8 billion in 1998.Data warehousing technologies have been successfully deployed in many industries: manufacturing (for order shipment and customer support), retail (for user profiling and inventory management),telecommunications (for call analysis and fraud detection ), utilities (for power usage analysis), and healthcare (for outcomes analysis). This paper presents a roadmap of data warehousing technologies, focusing on the special requirements that data warehouses place on database management systems (DBMSs).