Sams Teach Yourself SQL in 21 Days, Fourth Edition

Today's Database Landscape

Computing technology has made a permanent change in the ways businesses work around the world. Information that was at one time stored in warehouses full of filing cabinets can now be accessed instantaneously at the click of a mouse button. Orders placed by customers in foreign countries can now be instantly processed on the floor of a manufacturing facility.

Although 20 years ago much of this information had been transported onto corporate mainframe databases, offices still operated in a batch-processing environment. If a query needed to be performed, someone notified the management information systems (MIS) department, and then the requested data was delivered as soon as possible (although often not soon enough). ...