In the past year or two, a growing split has occurred in the database market. Similar to a giant iceberg, this split is about to carve off a huge new piece that will have its own identity and direction. We call this new half of the database market data warehousing.
Data warehousing is that part of relational technology that deals with getting the data out.
Data warehousing is a direct descendant of what led the industry to relational technology in the first place. Back in the early 1980s, we didn't decide to turn all of our IS shops upside down just because we were in love with transaction processing. We wanted better information. Transaction processing, entity-relationship diagrams, CASE tools, and all of the other OLTP apparatus came much later. Once we got hooked on relational databases, most of us realized that we had some serious work to do to make these databases production-ready.