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原创 Linux操作系统 作者:lawzjf 时间:2007-11-30 00:00:00 0 删除 编辑

Dr. Codd formally presented his new relational model in a landmark work titled “A Relational Model of Data for Large Shared Databanks” in June 1970.1 He based his new model on two branches of mathematics—set theory and first-order predicate logic. Indeed, the name of the model itself is derived from the term relation,which is part of set theory. (A widely held misconception is that the relational model derives its name from the fact that tables within a relational database can be related to one another. Now that you know the truth, you’ll have a peaceful, restful sleep tonight!)

------SQL Queries for Mere Mortals®
Second Edition

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