Abstract
Data warehousing and on-line analytical processing (OLAP)
are essential elements of decision support, which has
increasingly become a focus of the database industry. Many
commercial products and services are now available, and all
of the principal database management system vendors now
have offerings in these areas. Decision support places some
rather different requirements on database technology
compared to traditional on-line transaction processing
applications. This paper provides an overview of data
warehousing and OLAP technologies, with an emphasis on
their new requirements. We describe back end tools for
extracting, cleaning and loading data into a data warehouse;
multidimensional data models typical of OLAP; front end
client tools for querying and data analysis; server extensions
for efficient query processing; and tools for metadata
management and for managing the warehouse. In addition to
surveying the state of the art, this paper also identifies some
promising research issues, some of which are related to
problems that the database research community has worked
on for years, but others are only just beginning to be
addressed. This overview is based on a tutorial that the
authors presented at the VLDB Conference, 1996.