多维数据模型在面向对象数据库中的应用

【作者】 梁文菲；

【导师】 黄厚宽；

【作者基本信息】 北京交通大学 ， 计算机软件与理论， 2007， 硕士

【摘要】 自上世纪80年代,关系型数据库(Relation Database, RDB)以良好的可操作性和优越的性能价格比逐渐取代文件系统、层次数据库系统和网状数据库系统,成为数据库的主流技术,市场上推出的数据库管理系统产品几乎都是支持关系模型的。但是,随着应用复杂性的提高,RDB已经越来越不能满足人们的需要,由于面向对象技术的不断发展,关系模型与面向对象模型之间的“阻抗失谐(Impedance Mismatch)”问题也越发显得严重。而基于对象模型的面向对象数据库(Object-Oriented Database,OODB)虽然从根本上解决了阻抗失谐问题,但是由于其在支持SQL方面上的不足使得其发展受到很大制约。本文介绍一种新的多维数据模型——后关系模型,以及基于此模型的后关系型数据库Caché。该数据库的统一数据架构(Unified Data Architecture,UDA)支持用户自由地以对象,SQL,多维数组方式访问数据库。从广义上来说,后关系数据库属于面向对象数据库的范畴。因此,多维数据模型为面向对象数据库的发展开辟了一条新途径。本文着重从理论上分析三种模型的转换关系,并且结合XML、OLAP等数据库相关技术阐述多维数据模型的优势。最后结合具体实例演示Caché如何以三种方式访问数据。更多还原

【Abstract】 Since 80’s in last century, relation database (RDB) has been a substitute for file system, hierarchical databases and network database because of its nice maneuverability and predominant cost performance and become dominating technology of the database. Also newly-developed database management products are nearly all support to the the relation database.However, in the condition that application become more complex, RDB couldn’t fulfill people’ needs anymore. Due to the gradual development of object-oriented technology, impedance mismatch between RDB and object-oriented technology become more serious. Though object-oriented database based on object model thoroughly solved the problem of impedance mismatch, its development is hindered because of its lack on supporting SQL.In this thesis, a new multidimensional model—Post-Relation Model is introduced, and Post-Relation database—Cachébased on this model. Unified data architecture in this database allows users to select freely ways, which are manners of objects,SQL,or multidimensional array to access to the database. Therefore, multidimensional model pioneered a new way for the development of object-oriented database.As far as to this essay, transform of three models are mainly analysed the oretically, as well as the expatiation on the advantage of multidimensional model combined with the Database related technologies such as XML, OLAP. Finally a demonstration with a example is given to show how the Cachéaccess to the database in three ways.更多还原