对象视图与外模式

视图和外模式都是数据库技术中很有用的基本概念，它们的共同特征是可用来对数据库模式进行抽象。本文讨论了在面向对象模型中引入视图机制的一些问题，并提出了用视图构成数据库外模式的初步方案。     

Modularizing application and database evolution – an aspect‐oriented framework for orthogonal persistence

In the maintenance of software applications, database evolution is one common difficulty. In object‐oriented databases, this process comprises schema evolution and instance adaptation. Both tasks usually require significant effort from programmers and database administrators. In this paper, we propose orthogonal persistence and aspect‐oriented programming to support semi‐transparent database evolution. A default mechanism for instance evolution is defined, but the user may provide modularized solutions using the aspect‐oriented paradigm. We present our framework AOF4OOP to test the feasibility of our proposed approach. This prototype allows programmes to transparently access data in other versions of the database schema. We evaluate our framework, comparing it to related approaches using two real applications and measuring the improvement of the productivity of the programmer. Copyright © 2016 John Wiley & Sons, Ltd.     

异构数据源模式集成方法研究

异构信息系统集成中的模式集成是核心部分,模式集成的关键是选择合适的公共数据模型来实现全局视图和局部数据源模式之间的转换和映射,分析了现有数据集成系统的研究和开发现状,在Wrapper/Mediator结构的基础上研究了基于扩展HDM公共数据模型的异构信息系统数据集成环境的框架,HDM具有良好的表达能力和操作性能,本文给出了HDM的形式化描述以及基于HDM的模式转换方法,讨论了基于HDM的模式集成的若干关键技术并对进一步研究做了展望.     

MIDS／BUAA中模式演进的实现

本文是＜＜ＭＩＤＳ／ＢＵＡＡ中的模式演进＞＞一文的续篇，文中描述了ＭＩＤＳ／ＢＵＡＡ模式演进操作的语义，探讨了模式的变化传播对实例及方法（和应用）的影响，论述了演进操作的完全性和有效性，阐述了ＭＩＤＳ／ＢＵＡＡ模式演进的实现途径。     

MIDS／BUAA的模式管理器与对象管理器的设计

本文首先回顾了ＭＩＤＳ／ＢＵＡＡ总体设计中相关的部分重要内容，ｕｎｉｖＯｂｊｅｃｔ对象定义，持久性规则、库模式和ＭＩＤＳ的功能构成等。然后重点介绍了ＭＩＤＳ／ＢＵＡＡ中两个核心模块；模式管理器ＳＭ和对象管理器ＯＭ的思想，基本任务和实现途径；最后给出了ＭＩＤＳ／ＢＵＡＡ类库的层次结构。     

演绎对象数据库SD-DOOD中继承性的实现算法

介绍了演绎对象数据库SD DOOD系统的结构,给出了系统中可以实现的继承方法以及与实现这些方法有关的模式、实例、查询算法,并对算法的时间复杂度进行了分析。实验结果表明算法是可行的和有效的。     

Resolution of Semantic Heterogeneity in Database Schema Integration Using Formal Ontologies

This paper addresses the problem of handling semantic heterogeneity during database schema integration. We focus on the semantics of terms used as identifiers in schema definitions. Our solution does not rely on the names of the schema elements or the structure of the schemas. Instead, we utilize formal ontologies consisting of intensional definitions of terms represented in a logical language. The approach is based on similarity relations between intensional definitions in different ontologies. We present the definitions of similarity relations based on intensional definitions in formal ontologies. The extensional consequences of intensional relations are addressed. The paper shows how similarity relations are discovered by a reasoning system using a higher-level ontology. These similarity relations are then used to derive an integrated schema in two steps. First, we show how to use similarity relations to generate the class hierarchy of the global schema. Second, we explain how to enhance the class definitions with attributes. This approach reduces the cost of generating or re-generating global schemas for tightly-coupled federated databases.     

一种时序数据模式演化的跟踪与查询方法

在物联网与大数据应用蓬勃发展的背景下,各类感知设备产生海量的时序数据,设备管理软件版本的快速迭代导致时序数据的模式演化问题日益凸显.模式演化要求对数据模式进行版本管理,使数据进行模式变更时不产生信息损失,且支持对数据跨模式版本进行读写操作.结合流行的时序数据库管理系统,调研总结了各类数据库管理系统对模式演化的支持情况,对时序数据及其模式进行了形式化表述,对其模式演化的过程进行了分析,设计了一种面向时序数据的模式演化跟踪及查询方法,形式化表达了模式跟踪及跨模式版本查询的整体框架与关键步骤,并在时序数据库Apache IoTDB上进行了实现与测试.最后,分析了实现系统的性能,并展望了未来研究方向.     

基于多中间件的数据集成方案

为了实现分布的异构数据集成,解决"信息孤岛"问题,结合J2EE架构的优势和许多成功的数据集成方案,提出了基于数据访问中间件、消息中间件、数据源集成中间件的数据集成方案.详细讲述了该集成方案的架构和实现,实现结果表明该方案明显提高了数据集成的效率.最后,结合最新技术发展趋势对数据集成的研究前景做出了展望.     

An Ontology-Based Framework for Semi-Automatic Schema Integration

Currently, schema integration frameworks use approaches like rule-based, machine learning, etc. This paper presents an ontology-based wrapper-mediator framework that uses both the rule-based and machine learning strategies at the same time. The proposed framework uses global and local ontologies for resolving syntactic and semantic heterogeneity, and XML for interoperability. The concepts in the candidate schemas are merged on the basis of the similarity coefficient, which is calculated using the defined rules and the prior mappings stored in the case-base.