Re: Origin of the concept of "data model"

From: Ken North <>
Date: Wed, 19 May 2004 13:57:44 -0700
Message-ID: <c8ghjt$iru$>

"Leandro Guimaraens Faria Corsetti Dutra" <> wrote in message

> So from your research, it seems that while Codd has put it all
> together, there was some tentative interesting work before... as one
> should expect if not for this romantic myth of invention.

The relational model evolved over time. For example, by 1990, Chris Date was describing the relational model in three parts ("Introduction to Database Systems"):

  • relational data structure
  • relational integrity rules
  • relational algebra.

Childs' 1968 papers and Codd's 1970 paper discussed structure (independent sets, no fixed structure, access by name instead of by pointers) and operations (union, restriction, etc.). Childs' papers included benchmark times for doing set operations on an IBM 7090. Codd's 1970 paper introduced normal forms, and his subsequent papers introduced the integrity rules.

What's interesting is the University of Michigan connection. Codd, Bing Yao, and Michael Stonebreaker were graduates. Some of the work done at University of Michigan during that time (Childs' STDS, Ash and Sibley's TRAMP relational memory) was for the CONCOMP project. It was funded by the US government and the research was available only to "qualified requesters". Received on Wed May 19 2004 - 22:57:44 CEST

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