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软件学报  1995 

THE ATTRIBUTE INHERITANCE IN NF2 RELATIONAL MODEL
NF2关系模型与属性继承

Keywords: NF2 relational model,relational operation,class,subclass,inheritance
NF2关系模型,关系运算,类.子类,属性继承

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Abstract:

Combining object oriented model with value-based model would help getting the merits of both models. In this paper, based on NF2 relational model with composited tuple identity, the operations of projection if and natural join keeping the nested structure of relations, are given. From this, the authors have studied the semantics and formallied definition for class, subclass, attribute inheritance in NF2 relational model, introducing a special attribute R" and concept of S-subclass, discussed the common sub class and multiple inheritance. All of the discussions are based on composited tuple identity, possessing the features in O-O model.

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