数据库领域图灵奖获得者.doc

数据库领域图灵奖获得者
several group number, then with b ± a, =c,c is is methyl b two vertical box between of accurate sizp number, then with b ± a, =c,c is is methyl b two vertical box between of accurate size. Per-2~3 measurement, such as proceeds of c values are equal and equal to the design value, then the vertical installation accurate. For example a, b, and c valueswhile on horizontal vertical errors for measurement, General in iron angle code bit at measurement level points grid errors, specific method is from baseline to methyl vertical box center line distance for a,, to b vertical box distance for b, list can measured
several group number, then with b ± a, =c,c is is methyl b two vertical box between of accurate size. Per-2~3 measurement, such as proceeds of c values are equal and equal to the design value, then the vertical installation accurate. For example a, b, and c valueswhile on horizontal vertical errors for measurement, General in iron angle code bit at measurement level points grid errors, specific method is from baseline to methyl vertical box center line distance for a,, to b vertical box distance for b, list can measured
several group number, then with b ± a, =c,c is is methyl b two vertical box between of accurate size. Per-2~3 measurement, such as proceeds of c values are equal and equal to the design value, then the vertical installation accurate. For example a, b, and c valueswhile on horizontal vertical errors for measurement, General in iron angle code bit at measurement level points grid errors, specific method is from baseline to methyl vertical box center line distance for a,, to b vertical box distance for b, list can measured
青睐。但无论这个预言是否实现，巴赫曼作为数据库技术先驱的历史作用和地位是学术界和产业界普遍承认的。
埃德加·科德
在数据库技术发展的历史上，1970年是发生伟大转折的一年。这一年的6月，IBM圣约瑟研究实验室的高级研究员埃德加·科德（Edgar Frank Codd）在Communications of ACM上发表了题为“用于大型共享数据库的关系数据模型”一文。
    ACM后来在1983年把这篇论文列为从1958年以来的四分之一个世纪中具有里程碑式意义的最重要的25篇研究论文之一，因为它首次明确而清晰地为数据库系统提出了一种崭新的模型即关系模型。
用关系的概念来建立数据模型，用以描