Edgar Codd

The English computer scientist Edgar Codd is the creator of the relational databases model, an extremely influential general theory of data management, the foundation of RDBMS (Relational Databases Management Systems), used everywhere nowadays.

In the early 1940s Edgar studied mathematics and chemistry at Exeter College, Oxford, before serving as a pilot in the Royal Air Force during World War II. In 1948, after graduating from Oxford, he moved to New York and was soon hired by IBM as a programmer for the Selective Sequence Electronic Calculator, IBM’s first electronic computer, an experimental machine with 12500 vacuum tubes. He then invented a novel “multiprogramming” method for the pioneering IBM 7040 STRETCH computer. This method enabled STRETCH, the forerunner to modern mainframe computers, to run several programs at the same time. In 1953, disappointed by the USA policy, Codd moved to Ottawa, Canada. A decade later he returned to the USA and received his doctorate in computer science from the University of Michigan. Two years later he moved to San Jose, California, to work at IBM’s San Jose Research Laboratory.

In the 1960s and 1970s, Codd worked out his theories of data arrangement, based on mathematical set theory. He wanted to store data in cross-referenced tables, allowing the information to be presented in multiple permutations. It was a revolutionary approach. In 1969 he published an internal IBM paper, describing his ideas for replacing the hierarchical or navigational structure with simple tables containing rows and columns, but without great success and interest. Codd firmly believed that computer users should be able to work at a more natural-language level and not be concerned about the details of where or how the data was stored. In 1970 Codd published his landmark paper, A Relational Model of Data for Large Shared Data Banks.

Codd’s concept of data arrangement was seen within IBM as an “intellectual curiosity” at best and, at worst, as undermining IBM’s existing products. Codd’s ideas however were picked up by local entrepreneurs and resulted in the formation of firms such as Oracle (today the number two independent software firm after Microsoft), Ingres, Informix, and Sybase.

Let’s see how Don Chamberlin, an IBM colleague of Codd and coinventor of SQL, was acquainted with Codd’s ideas: “…since I’d been studying CODASYL (the language used to query navigational databases), I could imagine how those queries would have been represented in CODASYL by programs that were five pages long, that would navigate through this labyrinth of pointers and stuff. Codd would sort of write them down as one-liners. … They weren’t complicated at all. I said, ‘Wow.’ This was kind of a conversion experience for me. I understood what the relational thing was about after that.”

To Codd’s disappointment, IBM proved slow to exploit his suggestions until commercial rivals started implementing them. Initially, IBM refused to implement the relational model at all for business reasons (to preserve revenue from its current database implementation—IMS/DB.

In 1973 IBM finally included the relational model of Codd in his plans, for the System R subproject, but Codd was not involved in the project. Among the critical technologies developed for System R is the Structured Query Language (SQL), (initially called SEQUEL) developed by Chamberlin and Ray Boyce. Boyce later worked with Codd to develop the Boyce-Codd Normal Form for efficiently designing relational database tables so information was not needlessly duplicated in different tables.

In 1981 IBM released to market its first relational database product, SQL/DS. DB2, initially for large mainframe machines, was announced in 1983. IBM’s DB2 family of databases proved to be one of IBM’s most successful software products and is incorporated in the operating systems of the mainframe and middleware servers of IBM.

Still, in IBM, Codd continued to develop and extend his relational model. As the relational model started to become fashionable in the early 1980s, Codd fought a sometimes bitter campaign to prevent the term from being misused by database vendors who had merely added a relational veneer to older technology. As part of this campaign, he published his famous 12 rules to define what constituted a relational database.

Later he joined up with the British database guru Chris Date, whom Codd had introduced to San Jose in 1971, to form the Codd and Date Consulting Group. The company, which included Codd’s second wife Sharon Weinberg, made a good living from conducting seminars, writing books, and advising major database vendors. Codd never became rich like the entrepreneurs like Larry Ellison, who exploited his ideas. He remained active as a consultant until 1999.

Biography of Ted Codd

Edgar (Ted) Frank Codd was born on 19 August 1923, in Fortuneswell, on the Isle of Portland in the county of Dorset on the south coast of England. He was the youngest of seven children of Edgar Codd, a leather manufacturer, and Katherine Adcock, a schoolteacher.

During the 1930s Codd attended Poole Grammar School in Dorset. He was awarded a full scholarship to Oxford University (Exeter College), where he initially read chemistry (1941-1942). In 1942, despite the fact that he was eligible for a deferment because of his studies, Codd volunteered for active duty and became a flight lieutenant, then captain, in the Royal Air Force Coastal Command. After the war, in 1945, he returned to Oxford to complete his studies, switching to mathematics and obtaining his degree in 1948.

As part of his service in the RAF, Codd was sent to the United States for aviation training. That experience led to a lifelong love of recreational flying, and also to a recognition that the United States had a great deal to offer for someone of a creative bent like himself. As a consequence, he emigrated to the United States soon after graduating in 1948. After a brief period with Macy’s in New York City, working as a sales clerk in the men’s sportswear department, he found a job as a mathematics lecturer at the University of Tennessee in Knoxville, where he taught for six months.

Codd’s computing career began in June 1949 when he joined IBM in New York City as a programming mathematician. In 1953, Codd left the United States (and IBM) in protest against Senator Joseph McCarthy’s witch-hunting and moved to Ottawa, Canada, where he ran the data processing department for Computing Devices of Canada Limited (which was involved in the development of the Canadian guided missile program). A chance meeting with his old IBM manager led to his return to the U.S. in 1957 when he rejoined IBM in Poughkeepsie, New York. Codd retired from IBM in 1984 at the age of 61, after a serious injury resulting from a fall. Then he established two companies to provide worldwide lecturing and consulting services to vendors and users of database management systems and continues to write technical papers in response to ill-conceived criticisms of the relational model.

At the end of the 1960s, Codd became a U.S. citizen, though he never lost his British accent, his British sense of humor, or his British love for a good cup of tea.

Codd had a long list of honors and elected positions that were conferred on him during his lifetime, including IBM Fellow; Fellow of the Britain Computer Society; member of the National Academy of Engineering; member of the American Academy of Arts and Sciences; a Fellow of the Association for Computing Machinery. In 1981 he received the ACM Turing Award, the most prestigious award in the field of computer science.

Codd was married twice. First, in 1952, in Cambridge, Massachusetts, he married Elizabeth Shannon Forbes, a daughter of George Shannon Forbes, professor emeritus of chemistry at Harvard. They had four children: Katherine, David, Frank, and Ronald. They divorced in 1978 and in 1990 Codd married Sharon Boroff Weinberg.

The genuine computing pioneer Edgar Frank Codd died of heart failure at his home in Williams Island, Florida, on 18 April 2003.