E. F. Codd là ai???

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E. F. Codd là ai???

Post  Admin on 4/12/2007, 10:03

E. F. Codd là ai???
Edgar Frank "Ted" Codd (August 23, 1923 – April 18, 2003) was a British computer scientist who made seminal contributions to the theory of relational databases. While working for IBM, he created the relational model for database management. He made other valuable contributions to computer science, but the relational model, a very influential general theory of data management, remains his most memorable achievement.

Contents

* 1 Biography
* 2 See also
* 3 References
* 4 Notes

[edit] Biography

Edgar Frank Codd was born on the Isle of Portland, in England. After attending Poole Grammar School, he studied mathematics and chemistry at Exeter College, Oxford, before serving as a pilot in the Royal Air Force during the Second World War. In 1948, he moved to New York to work for IBM as a mathematical programmer. In 1953, angered by Senator Joseph McCarthy, Codd moved to Ottawa, Canada. A decade later he returned to the U.S. and received his doctorate in computer science from the University of Michigan in Ann Arbor. Two years later he moved to San Jose, California to work at IBM's Almaden Research Center.

In the 1960s and 1970s he worked out his theories of data arrangement, issuing his paper "A Relational Model of Data for Large Shared Data Banks" in 1970, after an internal IBM paper one year earlier.[citation needed] To his disappointment, IBM proved slow to exploit his suggestions until commercial rivals started implementing them.

Initially, IBM refused to implement the relational model in order to preserve revenue from IMS/DB. Codd then showed IBM customers the potential of the implementation of its model, and they in turn pressured IBM. Then IBM included in its Future Systems project a System R subproject — but put in charge of it developers who were not thoroughly familiar with Codd's ideas, and isolated the team from Codd. As a result, they did not use Codd's own Alpha language but created a non-relational one, SEQUEL. Even so, SEQUEL was so superior to pre-relational systems that it was copied, based on pre-launch papers presented at conferences, by Larry Ellison in his Oracle Database, which actually reached market before SQL/DS — due to the then-already proprietary status of the original moniker, SEQUEL had been renamed SQL.

Codd continued to develop and extend his relational model, sometimes in collaboration with Chris Date. One of the normalized forms, the Boyce-Codd Normal Form, is named after Codd. As the relational model started to become fashionable in the early 1980s, Codd fought a sometimes bitter campaign to prevent the term being misused by database vendors who had merely added a relational veneer to older technology. As part of this campaign, he published his 12 rules to define what constituted a relational database. His campaign extended to the SQL language, which he regarded as an incorrect implementation of the theory. This made his position in IBM increasingly difficult, so he left to form his own consulting company with Chris Date and others.

Edgar Codd coined the term OLAP and wrote the twelve laws of online analytical processing, although these were never truly accepted after it came out that his white paper on the subject was paid for by a software vendor; he also extended the ideas in the relational model to cover database design issue in his RM/T. Codd also contributed knowledge in the area of cellular automata.

Codd received a Turing Award in 1981 and in 1994 he was inducted as a Fellow of the Association for Computing Machinery[1] .

Edgar F. Codd died of heart failure at his home in Williams Island, Florida at the age of 79 on Friday, April 18, 2003. [1]

In 2004, SIGMOD renamed its highest prize, SIGMOD Innovations Award, in his honour.
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