A Relational Object Model
A Relational Object Model
复制标题
关系对象模型
DOI：
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
H. Schek
中科院分区：
文献类型：
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作者：
M. Scholl;H. Schek
关系模型及其扩展通常被认为与面向对象不兼容。然而，一方面嵌套关系提供了对象模型所需的复杂对象特征。特别是，强大的查询语言利用复杂的数据结构，同时保持声明性，面向集合的范式的优势。另一方面，对象模型为高级建模提供了语义丰富的构造，以及操作和数据的抽象。在本文中，我们展示了一个进化的路径，从关系，基本上是嵌套关系，面向对象的数据模型和查询语言。基本上，允许递归定义嵌套关系模式会产生必要的w.r.t.结构查询语言，即，嵌套关系代数，延续到这个“网络”模型。作为面向对象的协作系统集成的第一步，必须支持对象的不同视图。我们提出了一个强大的视图定义工具，基本上允许对象视图以及关系视图定义在我们的对象代数。
The relational model and its extensions are often considered incompatible with object-orientation. However, on the one hand nested relations provide the complex object features demanded by object models. Particularly, powerful query languages exploit the complex data structure while keeping the advantages of the declarative, set-oriented paradigm. On the other hand, object models provide semantically rich constructs for advanced modeling, and abstractions of operations as well as data. In this paper, we show an evolutionary path from relational, essentially nested relational, to object-oriented data models and query languages. Basically, allowing nested relation schemes to be recursively defined yields the necessary w.r.t. structure. The query language, i.e., nested relational algebra, carries over to this “network” model. As a first step towards the object-oriented integration of cooperative systems, different views onto the objects have to be supported. We present a powerful view definition facility that basically allows object views as well as relational views to be defined in our object algebra.