Heirarchically structured directories have recently proliferated with the growth of the Internet, and are being used to store not only address books and contact information for people, but also personal profiles, network resource information, and network and service policies. These systems provide a means for managing scale and heterogeneity, while allowing for conceptual unity and autonomy across multiple directory servers in the network, in a way for superior to what conventional relational or object-oriented databases offer. Yet, in deployed systems today, much of the data is modeled in an ad hoc manner, and many of the more sophisticated "queries" involve navigational access.
In this paper, we develop the core of a formal data model for network directories, and propose a sequence of efficiently computable query languages with increasing expressive power. The directory data model can naturally represent rich forms of heterogeneity exhibited in the real world. Answers to queries expressible in our query languages can exhibit the same kinds of heterogeneity. We present external memory algorithms for the evaluation of queries posed in our directory query languages, and prove the efficiency of each algorithm in terms of its I/O complexity. Our data model and query languages share the flexibility and utility of the recent proposals for semi-structured data models, while at the same time effectively addressing the specific needs of network directory applications, which we demonstrate by means of a representative real-life example.
分层结构的目录最近随着Internet的增长而激增,不仅用于存储人员的通讯录和联系信息,而且还用于存储个人资料,网络资源信息以及网络和服务策略。这些系统提供了一种管理规模和异构性的方法,同时允许跨网络中多个目录服务器的概念上的统一和自治,其方式要优于传统的关系数据库或面向对象的数据库。但是,在当今已部署的系统中,许多数据是以临时方式建模的,并且许多更复杂的“查询”都涉及导航访问。 P>
在本文中,我们开发了网络目录的正式数据模型的核心,并提出了一系列具有可增强表达能力的可有效计算的查询语言。目录数据模型可以自然地代表现实世界中丰富的异构形式。用我们的查询语言表达的查询的答案可以表现出相同的异质性。我们提出了用于评估以目录查询语言构成的查询的外部存储器算法,并就其I / O复杂性证明了每种算法的效率。我们的数据模型和查询语言具有针对半结构化数据模型的最新提议的灵活性和实用性,同时有效地满足了网络目录应用程序的特定需求,我们将通过一个有代表性的真实示例来进行演示。 P>
机译:查询和导航活动目录-Active Directory查询
机译:网络目录查询的分布式评估
机译:目录知识,查询流和基于加权状态空间树的自动Web查询分类
机译:查询网络目录
机译:目录在信息中心网络中辅助路由内容=信息中心网络中的目录辅助路由内容
机译:CUFID查询:通过基于随机游走的网络流量估计进行精确的网络查询
机译:网络目录查询的分布式评估
机译:农村卫生网络目录:剖析网络信息技术使用。