A Transaction Model for XML Databases

The hierarchical and semistructured nature of XML data may cause complicated update behavior. Updates should not be limited to entire document trees, but should ideally involve subtrees and even individual elements. Providing a suitable scheduling algorithm for semistructured data can significantly improve collaboration systems that store their data—e.g., word processing documents or vector graphics—as XML documents. In this paper we show that concurrency control mechanisms in CVS, relational, and object-oriented database systems are inadequate for collaborative systems based on semistructured data. We therefore propose two new locking schemes based on path locks which are tightly coupled to the document instance. We also introduce two scheduling algorithms that can both be used with any of the two proposed path lock schemes. We prove that both schedulers guarantee serializability, and show that the conflict rules are necessary.     

XML在移动数据库同步服务中的应用研究

SwiftDB是东南大学计算机科学与工程学院数据库及信息系统研究室研制的移动数据库系统,该文在移动数据库同步服务中应用XML进行语义合并、冲突检测,消除了操作冗余,简化了暂态事务,减少了同步耗时,提高了同步事务处理的成功率。     

Transaction management in distributed heterogeneous database management systems

Current distributed, heterogeneous database management systems (DBMSs) address the issue of distributed transaction management (DTM) in two different ways: some systems rely solely on unmodified local transaction managers (LTMs), thereby helping preserve local DBMS autonomy, but limit functionality (e.g. allow only unsynchronized retrievals, preclude distributed updates, etc.); others maintain full functionality but require the (re)design of the LTMs to enforce homogeneous DTM across all heterogeneous DBMSs, thereby giving up most of the local DBMS autonomy.

The goal of the work presented here is to establish the minimum set of modifications to LTMs that allow synchronized retrievals and distributed updates (whenever semantic conflicts can be resolved), and will continue to maintain a high degree of local DBMS autonomy. The problems of: (1) distribution of responsibility between DTM and LTMs, (2) concatenation of functionally-equivalent LTM mechanisms, and (3) providing compensation mechanisms for functionally-limited LTMs are introduced. Solutions to the above problems are shown to exist. However, the interconnection of autonomous, heterogeneous DBMSs is significantly more difficult than anticipated, despite communication standardization and current optimism.     

基于XML的交易界面开发语言与运行时引擎

针对银行、证券、邮政等交易应用环境的特定需求,提出了一种基于XML的交易界面开发语言——TXUL,实现了交易界面描述与业务逻辑代码的分离,从而降低了交易界面开发与维护的难度,并利用引用机制使界面描述代码的可重用性得到增强。本文详细阐述了TXUL及其运行时引擎的设计和实现过程,通过UML描述TXUL的语法结构并映射为XML Schema,给出了一个基于Eclipse RCP的TXUL应用示例。     

Transaction Management in Distributed Database System POREL

This paper describes the architecture and implementation algorithm of a transaction managementsuhsystem (TM) in the distributed database system POREL.The TM has been reimplemented on VAX11/750.     

Integrating model management with data management in decision support systems

Because of the increasing complexity of the problems faced by decision makers and the nature of decision support systems, decision models are becoming more and more crucial to their success. In this paper, a general framework for model management, which can integrate model management and data management and handle issues in model management such as model creation, model modification and model use is proposed.     

XML data update management in XML-enabled database

With the increasing demand for a proper and efficient XML data storage, XML-Enabled Database (XEnDB) has emerged as one of the popular solutions. It claims to combine the pros and limit the cons of the traditional Database Management Systems (DBMS) and Native XML Database (NXD). In this paper, we focus on XML data update management in XEnDB. Our aim is to preserve the conceptual semantic constraints and to avoid inconsistencies in XML data during update operations. In this current era when XML data interchange mostly occurs in a commercial setting, it is highly critical that data exchanged be correct at all times, and hence data integrity in XML data is paramount. To achieve our goal, we firstly classify different constraints in XML documents. Secondly, we transform these constraints into XML Schema with embedded SQL annotations. Thirdly, we propose a generic update methodology that utilizes the proposed schema. We then implement the method in one of the current XEnDB products. Since XEnDB has a Relational Model as the underlying data model, our update method uses the SQL/XML as a standard language. Finally, we also analyze the processing performance.     

Current approaches to XML management

The Extensible Markup Language has become the standard for information interchange on the Web. We study the data- and document-centric uses of XML management systems (XMLMS). We want to provide XML data users with a guideline for choosing the data management system that best meets their needs. Because the systems we test are first-generation approaches, we suggest a hypothetical design for a useful XML database that could use all the expressive power of XML and XML query languages.     

Cooperative transaction hierarchies: Transaction support for design applications

Traditional atomic and nested transactions are not always well-suited to cooperative applications, such as design applications. Cooperative applications place requirements on the database that may conflict with the serializability requirement. They require transactions to be long, possibly nested, and able to interact with each other in a structured way. We define a transaction framework, called acooperative transaction hierarchy, that allows us to relax the requirement for atomic, serializable transactions to better support cooperative applications. In cooperative transaction hierarchies, we allow the correctness specification for groups of designers to be tailored to the needs of the application. We usepatterns andconflicts to specify the constraints imposed on a group's history for it to be correct. We also provide some primitives to smooth the operation of the members. We characterize deadlocks in a cooperative transaction hierarchy, and provide mechanisms for deadlock detection and resolution. We examine issues associated with failure and recovery.     

Efficient management of uncertainty in XML schema matching

Despite advances in machine learning technologies a schema matching result between two database schemas (e.g., those derived from COMA++) is likely to be imprecise. In particular, numerous instances of ??possible mappings?? between the schemas may be derived from the matching result. In this paper, we study problems related to managing possible mappings between two heterogeneous XML schemas. First, we study how to efficiently generate possible mappings for a given schema matching task. While this problem can be solved by existing algorithms, we show how to improve the performance of the solution by using a divide-and-conquer approach. Second, storing and querying a large set of possible mappings can incur large storage and evaluation overhead. For XML schemas, we observe that their possible mappings often exhibit a high degree of overlap. We hence propose a novel data structure, called the block tree, to capture the commonalities among possible mappings. The block tree is useful for representing the possible mappings in a compact manner and can be efficiently generated. Moreover, it facilitates the evaluation of a probabilistic twig query (PTQ), which returns the non-zero probability that a fragment of an XML document matches a given query. For users who are interested only in answers with k-highest probabilities, we also propose the top-k PTQ and present an efficient solution for it. An extensive evaluation on real-world data sets shows that our approaches significantly improve the efficiency of generating, storing, and querying possible mappings.     

Transaction management issues in a failure-prone multidatabase system environment

This paper is concerned with the problem of integrating a number of existing off-the-shelf local database systems into a multidatabase system that maintains consistency in the face of concurrency and failures.The major difficulties in designing such systems stem from the requirements that local transactions be allowed to execute outside the multidatabase system control, and that the various local database systems cannot participate in the execution of a global commit protocol. A scheme based on the assumption that the component local database systems use the strict two-phase locking protocol is developed. Two major problems are addressed: How to ensure global transaction atomicity without the provision of a commit protocol, and how to ensure freedom from global deadlocks.     

Transaction exchange management systems for successful systems integration

The objective of this paper is to discuss the strategy to be taken by computerized information system managers and developers in the evolving era of computer integrated manufacturing (CIM). Specifically, more concentration should be directed towards a standardized methodology for the management and handling of the transaction data which flows between two or more systems, rathr than upon the hardware and software technology used to “connect” those systems.     

XML sets stage for efficient knowledge management

IT managers use knowledge management (KM) tools to capture maintain, and exploit strategic information that their companies need to conduct business. This information might consist of data describing operational best practices, tactical marketing results such as assessment of a competitor's market share, or even the contents of laboratory notebooks. In every case, preserving the data's context is essential when acquiring, processing, or storing the information. The Extensible Markup Language provides a means for preserving this context. The paper considers how XML provides the context for turning a data set into information; KM provides the tools for managing this information     

基于XML的虚拟数据库管理系统

针对分布式数据同步时因为有异构的数据源而造成数据格式不统一,应用层进行同步的时候要进行相当复杂的转换并且维护起来也要耗费相当大的成本,提出了利用XML来统一异构数据源的格式,构建基于XML中间件的虚拟数据库.介绍此系统下的异构数据集成的思想和实现框架,同时详细介绍了该框架提供的服务功能及实现的关键技术.     

基于CBR和XML的知识管理系统架构研究

随着知识管理系统的广泛应用以及计算机信息技术的不断发展,开发智能化的知识管理系统成为研究的焦点。将人工智能技术运用于知识管理系统中,可有效地管理组织的显性知识、最大化地将隐性知识转换为显性知识,从而实现组织更大范围的知识共享。在对现有知识管理系统分析的基础上,提出基于CBR（case-basedreasoning）和XML（extensible markup language）智能化的知识管理系统架构。该架构适于对经验知识的管理。     

Data management support for database management

Summary Database management systems today face a rising demand for higher transaction rates and shorter response time. One of the essential requirements for meeting this demand is appropriate operating system support for database management functions. This paper proposes the introduction of the concept of consistency-preserving containers into data management in order to improve data management support for database management. Moreover, it presents the formal definition of a transactionoriented interface between data management and database management based on this concept, and introduces a locking scheme allowing high concurrency of transactions while guaranteeing consistency. Logging and recovery aspects of the concept are discussed.     

Bilingual legal document retrieval and management using XML

In certain bilingual and multi‐lingual societies, translated legal documents are as important as the original legal documents because they have the same legal status as the originals. However, there is little reported work on the retrieval and management of bilingual legal documents. We describe the design and development of a bilingual document retrieval and management prototype, called ELDoS, which is used by court interpreters and judges from the Hong Kong Judiciary. Since the speed of retrieval is a major concern for user acceptance, and therefore for widespread deployment of the system, the architecture of the prototype is designed to balance the workload of the client and server. Extensible Markup Language (XML) is used to mark up the bilingual legal documents for a variety of document retrieval and management tasks. XML enables the use of XML Stylesheet Language Transformation (XSLT) to align bilingual data in the client, instead of the server, and improve alignment speed linearly with respect to the size of the document, using a high‐end PC, when the server has no concurrent access. The design of the interface was continually improved after extensive consultation with court interpreters and after the user acceptance tests. In our evaluation, the facilities for highlighting translated terms have a macro‐averaged precision of 90+% and a macro‐average recall of 80+%, which were considered acceptable by our users. We believe that the experience in the design and development of this prototype is applicable to other language pairs as well as to other domains. Copyright © 2002 John Wiley & Sons, Ltd.     

Knowledge management in decision support systems

This paper discusses a framework for knowledge management in a DSS. We assume decision making is based mainly on numerical data processing. Thus, we abstract data and knowledge as relations, and decision models as relators. Based on these two constructs, our framework allows a user to compose and experiment decision models interactively; it also provides decision information nonprocedurally through a knowledge processor.