模糊数据表示和xml数据库查询------外文翻译.doc
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模糊数据表示和xml数据库查询------外文翻译,real-world information including subjective opinions and judgments need imprecise data to bemodeled for representation and querying in databases. the extensible...
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Real-world information including subjective opinions and judgments need imprecise data to bemodeled for representation and querying in databases. The Extensible Markup Language (XML) hasbecome a de-facto standard for data modeling and exchange in recent years. Efforts on modelingimprecision and representing such data in XML have not been fully developed. In this paper, anXML based fuzzy data representation and querying system is presented. Complex and imprecisedata are represented using a fuzzy extension of XML. The representation forms the basis for asystem which enables fuzzy querying on XML documents using XQuery, a XML query language. The system also enables restructuring of XML Schemas through merging of elements of the XMLdocuments. By using this feature of the system, application specific XML Schema and XMLdocuments can be generated from the existing documents. Keywords'. Fuzzy query; XML; native XML databases.
1. Introduction
A database is an organized collection of data. Traditional database management systemsare particularly suited to represent crisp, well defined data using standard structures. However, real-world information includes subjective opinions and judgments that requirethe modeling of complex and imprecise data along with crisp data. The representation ofsuch uncertain and complex data in a database is still a research issue. The Extended NonFirst Normal Form (ExNF2) [1] data model is a model that has been proposed for therepresentation of such uncertain and imprecise data.
The Extensible Mark-up Language (XML) [2], [3], [4], [5] is widely used for datarepresentation and interchange. XML allows the separation of content and presentation, i.e., XML documents simply define the data representation and do not deal with thepresentation. XML can be used to represent complex and hierarchical information, whichare basic modeling constructs in the ExNF2 model.
This work is partially supported by the NSF Grant No. HRD-0401679, AHPCRC Contract No. DAAD19-01-2-0014 and ARL Contract No. DAAL01-98-2-0065. The content of this work does not reflect the position orpolicy of the sponsors and no official endorsement should be inferred. Choosing the most appropriate database management system to handle XML datadepends on the application and data structure. With increasingly large amount of databeing represented as XML documents, it becomes necessary to efficiently store and querythese XML documents. Native XML databases have several advantages over traditionaldatabase management systems in managing XML data. When the data is semi-structured, mapping it to a relational database results in either a large number of columns with nullvalues (which wastes space) or a large number of tables (which is inefficient). Anotherreason to store data in a native XML database is retrieva l speed. Depending on how thenative XML database physically stores data, it is possible to retrieve data much fasterthan a relational database. This is because the storage strategies used by native XMLdatabases store entire documents together physically or use physical (rather than logical) pointers between the parts of the document; permitting the documents to be retrievedeither without joins or with physical joins, both of which are faster than the logical joinsused by relational databases [11].
真实世界的信息，包括主观的意见和判断，需要不精确数据为蓝本来表示并在数据库中查询。近年来，可扩展标记语言（XML）事实上已经成为数据建模和交流的标准。在XML中，对不精确性的建模和代表这些数据做出的努力没有得到充分发展。本文中，提出了基于XML的模糊数据表示和查询系统。用模糊扩展的XML来表示复杂和不精确的数据。这种表示法形成了一个基础系统，能够在XML文档使用XML的一种查询语言XQuery进行模糊查询。该系统还可以通过XML架构重组，合并XML元素文件。通过使用此功能的系统，应用程序特定的XML架构和XML文件可以从现有的文件中产生。
关键字:模糊查询，XML,原生XML数据库。
1、简介
数据库是数据的一个有组织的集合。传统的数据库管理系统特别适合于代表那些使用标准结构的清晰、明确界定的数据，。然而，现实世界的信息，包括主观的意见和判断，需要复杂和不准确的数据建模同时也需要明确界定的数据。在数据库中代表这种不确定性和复杂的数据仍然是一个正在研究中的问题。扩展非第一范式（ExNF2）[1]数据模型是一个已为拟议的代表这种不确定和不精确数据模型。
可扩展标记语言（XML）[2][3][4][5]，被广泛用于数据代表和交换。XML允许内容和表现的分离，也就是说，XML文档简单定义了数据表示但是并不处理它的表现形式。XML可以用来表示复杂和层次性的信息，这是ExNF模型的基本造型结构。
选择最合适的数据库管理系统，以处理基于应用程序和数据结构的XML数据。随着越来越大的数据量作为XML文档表示，有必要有效地存储和查询这些XML文档。在管理XML数据中，原生的XML数据库比传统的数据库管理系统具有几个优点。当数据是半结构化时，映射到一个关系数据库结果中将导致大量的空列（浪费空间）或大量的表（低效的）。另一个在原生XML数据库存储数据的原因是检索速度。原生XML数据库在物理存储数据方面，检索数据比关系型数据库快得多。这是因为原生XML运用存储策略存储整个文件或在文件的各部分中使用物理（而不是逻辑）指针;..
1. Introduction
A database is an organized collection of data. Traditional database management systemsare particularly suited to represent crisp, well defined data using standard structures. However, real-world information includes subjective opinions and judgments that requirethe modeling of complex and imprecise data along with crisp data. The representation ofsuch uncertain and complex data in a database is still a research issue. The Extended NonFirst Normal Form (ExNF2) [1] data model is a model that has been proposed for therepresentation of such uncertain and imprecise data.
The Extensible Mark-up Language (XML) [2], [3], [4], [5] is widely used for datarepresentation and interchange. XML allows the separation of content and presentation, i.e., XML documents simply define the data representation and do not deal with thepresentation. XML can be used to represent complex and hierarchical information, whichare basic modeling constructs in the ExNF2 model.
This work is partially supported by the NSF Grant No. HRD-0401679, AHPCRC Contract No. DAAD19-01-2-0014 and ARL Contract No. DAAL01-98-2-0065. The content of this work does not reflect the position orpolicy of the sponsors and no official endorsement should be inferred. Choosing the most appropriate database management system to handle XML datadepends on the application and data structure. With increasingly large amount of databeing represented as XML documents, it becomes necessary to efficiently store and querythese XML documents. Native XML databases have several advantages over traditionaldatabase management systems in managing XML data. When the data is semi-structured, mapping it to a relational database results in either a large number of columns with nullvalues (which wastes space) or a large number of tables (which is inefficient). Anotherreason to store data in a native XML database is retrieva l speed. Depending on how thenative XML database physically stores data, it is possible to retrieve data much fasterthan a relational database. This is because the storage strategies used by native XMLdatabases store entire documents together physically or use physical (rather than logical) pointers between the parts of the document; permitting the documents to be retrievedeither without joins or with physical joins, both of which are faster than the logical joinsused by relational databases [11].
真实世界的信息，包括主观的意见和判断，需要不精确数据为蓝本来表示并在数据库中查询。近年来，可扩展标记语言（XML）事实上已经成为数据建模和交流的标准。在XML中，对不精确性的建模和代表这些数据做出的努力没有得到充分发展。本文中，提出了基于XML的模糊数据表示和查询系统。用模糊扩展的XML来表示复杂和不精确的数据。这种表示法形成了一个基础系统，能够在XML文档使用XML的一种查询语言XQuery进行模糊查询。该系统还可以通过XML架构重组，合并XML元素文件。通过使用此功能的系统，应用程序特定的XML架构和XML文件可以从现有的文件中产生。
关键字:模糊查询，XML,原生XML数据库。
1、简介
数据库是数据的一个有组织的集合。传统的数据库管理系统特别适合于代表那些使用标准结构的清晰、明确界定的数据，。然而，现实世界的信息，包括主观的意见和判断，需要复杂和不准确的数据建模同时也需要明确界定的数据。在数据库中代表这种不确定性和复杂的数据仍然是一个正在研究中的问题。扩展非第一范式（ExNF2）[1]数据模型是一个已为拟议的代表这种不确定和不精确数据模型。
可扩展标记语言（XML）[2][3][4][5]，被广泛用于数据代表和交换。XML允许内容和表现的分离，也就是说，XML文档简单定义了数据表示但是并不处理它的表现形式。XML可以用来表示复杂和层次性的信息，这是ExNF模型的基本造型结构。
选择最合适的数据库管理系统，以处理基于应用程序和数据结构的XML数据。随着越来越大的数据量作为XML文档表示，有必要有效地存储和查询这些XML文档。在管理XML数据中，原生的XML数据库比传统的数据库管理系统具有几个优点。当数据是半结构化时，映射到一个关系数据库结果中将导致大量的空列（浪费空间）或大量的表（低效的）。另一个在原生XML数据库存储数据的原因是检索速度。原生XML数据库在物理存储数据方面，检索数据比关系型数据库快得多。这是因为原生XML运用存储策略存储整个文件或在文件的各部分中使用物理（而不是逻辑）指针;..
