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2 as the world??™s first commercial relational database within a couple
of years (also changing its name to Relational Software, Incorporated). By 1985,
Oracle could claim more than 1,000 relational database customer sites. Curiously,
IBM would not embrace relational technology in a commercial product until the
Query Management Facility in 1983.
Why did relational database technology grow to become the de facto database technology?
A look back at previous database technology may help to explain this
phenomenon.
Database management systems were first defined in the 1960s to provide a common
organizational framework for data formerly stored in independent files. In 1964,
Charles Bachman of General Electric proposed a network model with data records
linked together, forming intersecting sets of data, as shown on the left in Figure 1-1.
This work formed the basis of the CODASYL Data Base Task Group. Meanwhile,
the North American Aviation??™s Space Division and IBM developed a second
approach based on a hierarchical model in 1965.


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