基于XML的数据交换与数据访问技术及其应用研究
摘要
Internet的高速发展使得全球的数据、资源紧密的联系在一起，网络这个巨大的资源库包含着大量不同平台、不同格式的数据，如何对这些数据进行有效的数据交换、访问及查询等是急需解决的问题。XML是软件行业对这些问题提出的解决方案，随着XML的标准化和广泛应用，主流厂商已经将XML集成到包括数据库引擎、开发工具、浏览器和操作系统在内的各种产品中，大量围绕XML建立起来的基础技术也日益普及。
然而，由于XML的自描述特点以及层状嵌套结构，使其比另一些同类文档更大也更加复杂，而XML已经被广泛地作为一种数据交换的方法来使用，被交换的文档如果过大就会降低应用程序的性能和可扩展性。压缩技术是提高交换效率的一种方法，但接收方需要对压缩文档完全解压才能够执行进一步的操作，在很多应用中这种方式并不适用，这就提出了如何在高效压缩的同时在压缩后的XML文档上进行查询等操作的问题；另一方面，由于XML文档的层次结构的特殊性，传统的文件级别的访问控制已经不能适应在元素、属性的级别上进行访问控制的需要，所以对只需要访问部分XML文档内容的用户进行有效的数据访问控制也是XML数据访问控制面临的一个问题。
本文就如何有效的进行基于XML的数据交换提出了一个支持在压缩数据上查询的XML压缩方案，支持XPath查询(XPath-query-friendly)，采用LZW与Huffman编码结合的方式在元素内容和属性值的粒度上进行压缩，并将XML文档的结构与数据分开单独进行压缩。论文描述了该方案的架构，设计的原则以及采用的主要技术，给出了与已有的压缩工具的压缩效果的比较。
在基于XML的数据访问控制方面，本文提出了一个利用用户、用户组数据和扩展后的XPath进行访问对象描述的XML数据访问控制方案，对该方案的架构，访问控制的主体、对象、授权规则和规则级别等进行了详细的介绍，并给出了应用示例。
最后，论文总结了完成的工作，并提出了方案中需要进一步研究的问题。
Data resources are closely interconnected with the popularity of the Internet. Web has become the biggest information resource which contains data of various platforms or formats. How to efficiently exchange, access or query the data is one of the serious problems emerge these years. XML is regarded as the solution to this problem by the software industry. And with the standardization and widely applcation of XML, main vendors have been integrating XML into many products such as database engines, development tools, Internet browsers and operating systems etc. Many XML-based technologies has been invented and developed.
XML is a self describing markup language with embedded document structure which makes the XML document is more verbose than other documents contain the same data. The size of the XML document will have an impact on the efficiency and scalability of the application. General compressing technologies are not proper in some circumstances for the receivers are always required to decompress the data completely to manupulate the original data (querying, validating etc.). The embedded document structure of XML also makes it difficult to perform access control because the traditional file level access control systems could not fulfill the requirement of element or attribute level access control.
In the paper we first present a scheme for XML-based data exchange which is an XPath-query-friendly compressor for XML. It leverages the LZW algorithm and Huffman encoding, compressing the XML data on element and attribute level and separating the structure of the document from the content. We describe the architecture of the system, the design principles and the technologies used, and we also present the compress results in contrast with other compressors.
Then we propose an XML data access control system which uses extended XPath and user or user group information to define the access object. We describe the architecture, the subject, object, access rules and the different levels of the rules. And we also illustrate the access control process with an example.
Finally we conclude the thesis and list future work.
然而，由于XML的自描述特点以及层状嵌套结构，使其比另一些同类文档更大也更加复杂，而XML已经被广泛地作为一种数据交换的方法来使用，被交换的文档如果过大就会降低应用程序的性能和可扩展性。压缩技术是提高交换效率的一种方法，但接收方需要对压缩文档完全解压才能够执行进一步的操作，在很多应用中这种方式并不适用，这就提出了如何在高效压缩的同时在压缩后的XML文档上进行查询等操作的问题；另一方面，由于XML文档的层次结构的特殊性，传统的文件级别的访问控制已经不能适应在元素、属性的级别上进行访问控制的需要，所以对只需要访问部分XML文档内容的用户进行有效的数据访问控制也是XML数据访问控制面临的一个问题。
本文就如何有效的进行基于XML的数据交换提出了一个支持在压缩数据上查询的XML压缩方案，支持XPath查询(XPath-query-friendly)，采用LZW与Huffman编码结合的方式在元素内容和属性值的粒度上进行压缩，并将XML文档的结构与数据分开单独进行压缩。论文描述了该方案的架构，设计的原则以及采用的主要技术，给出了与已有的压缩工具的压缩效果的比较。
在基于XML的数据访问控制方面，本文提出了一个利用用户、用户组数据和扩展后的XPath进行访问对象描述的XML数据访问控制方案，对该方案的架构，访问控制的主体、对象、授权规则和规则级别等进行了详细的介绍，并给出了应用示例。
最后，论文总结了完成的工作，并提出了方案中需要进一步研究的问题。
Data resources are closely interconnected with the popularity of the Internet. Web has become the biggest information resource which contains data of various platforms or formats. How to efficiently exchange, access or query the data is one of the serious problems emerge these years. XML is regarded as the solution to this problem by the software industry. And with the standardization and widely applcation of XML, main vendors have been integrating XML into many products such as database engines, development tools, Internet browsers and operating systems etc. Many XML-based technologies has been invented and developed.
XML is a self describing markup language with embedded document structure which makes the XML document is more verbose than other documents contain the same data. The size of the XML document will have an impact on the efficiency and scalability of the application. General compressing technologies are not proper in some circumstances for the receivers are always required to decompress the data completely to manupulate the original data (querying, validating etc.). The embedded document structure of XML also makes it difficult to perform access control because the traditional file level access control systems could not fulfill the requirement of element or attribute level access control.
In the paper we first present a scheme for XML-based data exchange which is an XPath-query-friendly compressor for XML. It leverages the LZW algorithm and Huffman encoding, compressing the XML data on element and attribute level and separating the structure of the document from the content. We describe the architecture of the system, the design principles and the technologies used, and we also present the compress results in contrast with other compressors.
Then we propose an XML data access control system which uses extended XPath and user or user group information to define the access object. We describe the architecture, the subject, object, access rules and the different levels of the rules. And we also illustrate the access control process with an example.
Finally we conclude the thesis and list future work.
引文
[1] XML1.0, http://www.w3.org/FR/2004/REC-xml-20040204/.
[2] XPath1.0, http://www.w3.org/TR/xpath.
[3] DOM, http://www.w3.org/DOM/DOMTR.
[4] SAX, http://www.saxproject.org/.
[6] XSLT1.0, http://www.w3.org/FR/xslt.
[7] OASIS XACML标准， http://www.oasis-open.org/committees/download.php/2406/oasis-xacml-1.0.pdf .
[8] WBXML, http://www.w3.org/1999/06/NOTE-wbxml-19990624/# Toc443384894.
[9] Mark Birbeck等, XML 高级编程，机械工业出版社。
[10] Don Box, Aaron Skonnard, John Lam, XML本质论，中国电力出版社。
[11] Elliotte Rusy Harold, W.Scott Means, 技术手册，中国电力出版社。
[12] John Robert Gardner, Zarella L.Rendon, XPath和XSLT—XML转换指南，机械工业出版社。
[13] Blake Dournaee,XML安全基础，清华大学出版社。
[14] Steve Muench,构建Oracle XML应用程序，中国电力出版社。
[15] Robert. C. Martin, 敏捷软件开发，中国电力出版社。
[16] Brian W. Cernghan, Rob Pike程序设计实践，机械工业出版社。
[17] 严蔚敏，吴伟民，数据结构(第二版)，清华大学出版社。
[18] 贺琛，陈肇雄，黄河燕，在嵌入式Internet系统中压缩XML文档的LZWX算法，计算机工程，2003年7月。
[19] 刘立军，基于XML数据交换的若干问题研究，中科院计算技术研究所，硕士论文，2001年6月。
[20] 何云升，基于XML的网络数据交换研究与实现，西安电子科技大学，硕士论文，2002年1月。
[21] 赵遐，基于XML的访问控制系统研究与实现，北京航空航天大学，硕士论文，2002年2月。
[22] Dan Suciu, XMill: an Efficient Compressor for XML Data, Proceedings of the 2000 ACM SIGMOD international conference on Management of data, ACM press, 2000.
[23] Sushil Jajodia, Michiharu Kudo, V.S. Subrahmanian, Provisional Authorization, IBM东京基础研究所, http://www.trl.ibm.com/projects/xrnl/xacl[wspec2k-kudo.pdf.
[24] Elisa Bertino, Elena Ferrari, Secure and Selective Dissemination of XML Document, ACM Transactions on Information and System Security, Vol. 5, No. 3, August 2002.
[25] Ernesto Damiani, Sabrina De Capitani di Vimercati, Stefano Paraboschi, Pierangela Samarati, Controlling Access to XML Document, IEEE INTERNET COMPUTING,
11～12, 2001.
[26] Fabio Simeoni, David Lievens, Richard Connor, Paolo Manghi, Language Bindings to XML, IEEE INTERNET COMPUTING, 1-2, 2003.
[27] Hon Chung MAK, Edmund, Shermann S.M. Chan, Qing Li, XML vs. Object Oriented XML: Motivations, Applications and Performance, Proceedings of the First International Symposium on Cyber Worlds(CW'02), 2002.
[28] E. Damiani, S. De Capitani di Vimercati, S. Paraboschi, P. Samarati, A Fine-Grained Access Control System for XML Documents, ACM Transactions on Information and System Security, Vol. 5, No. 2, 2002.5.
[29] YanIei Diao, Peter M. Fischer, Michael J. Franklin, Raymond To, YFilter: Efficient and Scalable Filtering of XML Documents, Proceedings of 18th International Conference on Data Engineering 2002, 2002.2.
[30] Hao He, Raymond K. Wong, A Role-Based Access Control Model For XML Repositories, First International Conference on Web Information Systems Engineering (WISE'00)-Volume 1, 2000.6.
[31] Emmanuel Pietriga, Jean-Yves Vion-Dury, Vincent Quint, VXT: A Visual Approach to XML Transformations, Proceedings of the 2001 ACM Symposium on Document engineering, 2001.
[32] Pankaj M. Tolani, Jayant R. Haritsa, XGRIND: A Query-friendly XML Compressor, 8th Int'l Conference on Data Engineering, 2002.
[33] Mark Nelson, LZW Data Compression, Dr. Dobbs' Journal, 1989.10.
[34] Weimin Li, XCOMP: AN XML COMPRESSION TOOL, Waterloo 大学硕士论文，2003。
[35] Marc Girardot, Neel Sundaresan, Millau: an encoding format for efficient representation and exchange of XML over the Web.
[36] Dare Obasanjo, 在使用XPath 查询XML文档时应了解和避免的事情，MSDN,http://www.microsoft.com/china/msdn/library/dnexxml/xm106172002.asp.
[37] W3C, What is XSL?, http://www.w3.org/Style/XSL/WhatIsXSL.html.
[38] Jane Fung,解码XML和DTD, IBM develperWorks,http://www-900.ibm.com/developerWorks/cn/xml/x-dtdint/index.shtml#ggviewer-of fsite-nav-13383528.
[39] David Mertz, XML问题#7W3C XML Schema 与文档类型定义(DTD)比较, IBM developerWorks, http://www-900.ibm.com/developerWorks/cn/xml/xml-matters/x-matters7.shtml.
[40] Murdoch Mactaggart,启用XML安全性—XML加密和XML签名简介，IBM developerWorks. http://www-900.ibm.com/developerWorks/cn/xml/s-xmlsec/index.shtml.
[41] XACL FAQ http//www.trl.ibm.com/projects/xml/xacl/xacl-faq.html.
[42] A Brief Introduction to XACML, http://www.oasis-open.org/committees/download.php/2713/Brief Introduction to XACML.html.
[43] 王咏刚，数据压缩技术概论, http://www.contextfree.net/wangyg/index.html.
[44] 王咏刚，数据压缩教程，
http://www.contextfree.net/wangyg/tech/benben/default.htm.
[45] Dan Wahlin,高效交换XML 文档，http://www.fawcette.com/china/XmlFile.aspx?ID=278.
[46] 郝斌，基于角色管理的系统访问控制，http://www-900.ibm.com/developerWorks/cn/security/syscontrol/index.shtml.
[47] David Mertz, XML 问题 #13 XML 和压缩—探索文档的平均信息量，IBM developerWorks,http://www-9OO.ibm.com/developerWorks/cn/xml/x-matters/part13/index.shtml#ggv iewer-offsite-nav-13383528.
[48] David Mertz, XML 问题 #19 XML 和压缩的进一步探讨—块级别压缩和资源负载, IBMdeveloperWorks, http://www-900.ibm.com/developerWorks/cn/xml/x-matters/part19/index.shtm1#ggv iewer-offsite-nav-13383528.
[49] Xalan C++1.7, http://xml.apache.org/xalan-c/.
[50] Xalan-dev mailing list archives, http://marc.theaimsgroup.com/?l=xalan-dev.
[51] apache DOM Programming Guide, http://xml.apache.org/xerces-c/program-dom.html.
[52] Xerces C++2.5.0, http://xml.apache.org/xerces-c/index.html.
[53] XMark-An XML Benchmark Project, http://monetdb.cwi.nl/xml/.
[54] Using Expat,http://www.xml.com/pub/a/1999/09/expat/index.html?page=2.
[55] XCeed, http://www.xceedsoft.com/products/Stream/.
[56] XMill,http://www.research.att.com/sw/tools/xmill/#ggviewer-offsite-nav-13383528.
[57] XGrind,http://sourceforge.net/projects/xgrind/#ggviewer-offsite-nav-13383528.
[58] Millau,http://www9.org/w9cdrom/154.154.htm1#ggviewer-offsite-nav-13383528.
[59] XCDE,http://roquefort.di.unipi.it/-ferrax/xcde/xcdelib.html.
[60] zlib,http://www.gzip.org/zlib/zlib docs.html.
[2] XPath1.0, http://www.w3.org/TR/xpath.
[3] DOM, http://www.w3.org/DOM/DOMTR.
[4] SAX, http://www.saxproject.org/.
[6] XSLT1.0, http://www.w3.org/FR/xslt.
[7] OASIS XACML标准， http://www.oasis-open.org/committees/download.php/2406/oasis-xacml-1.0.pdf .
[8] WBXML, http://www.w3.org/1999/06/NOTE-wbxml-19990624/# Toc443384894.
[9] Mark Birbeck等, XML 高级编程，机械工业出版社。
[10] Don Box, Aaron Skonnard, John Lam, XML本质论，中国电力出版社。
[11] Elliotte Rusy Harold, W.Scott Means, 技术手册，中国电力出版社。
[12] John Robert Gardner, Zarella L.Rendon, XPath和XSLT—XML转换指南，机械工业出版社。
[13] Blake Dournaee,XML安全基础，清华大学出版社。
[14] Steve Muench,构建Oracle XML应用程序，中国电力出版社。
[15] Robert. C. Martin, 敏捷软件开发，中国电力出版社。
[16] Brian W. Cernghan, Rob Pike程序设计实践，机械工业出版社。
[17] 严蔚敏，吴伟民，数据结构(第二版)，清华大学出版社。
[18] 贺琛，陈肇雄，黄河燕，在嵌入式Internet系统中压缩XML文档的LZWX算法，计算机工程，2003年7月。
[19] 刘立军，基于XML数据交换的若干问题研究，中科院计算技术研究所，硕士论文，2001年6月。
[20] 何云升，基于XML的网络数据交换研究与实现，西安电子科技大学，硕士论文，2002年1月。
[21] 赵遐，基于XML的访问控制系统研究与实现，北京航空航天大学，硕士论文，2002年2月。
[22] Dan Suciu, XMill: an Efficient Compressor for XML Data, Proceedings of the 2000 ACM SIGMOD international conference on Management of data, ACM press, 2000.
[23] Sushil Jajodia, Michiharu Kudo, V.S. Subrahmanian, Provisional Authorization, IBM东京基础研究所, http://www.trl.ibm.com/projects/xrnl/xacl[wspec2k-kudo.pdf.
[24] Elisa Bertino, Elena Ferrari, Secure and Selective Dissemination of XML Document, ACM Transactions on Information and System Security, Vol. 5, No. 3, August 2002.
[25] Ernesto Damiani, Sabrina De Capitani di Vimercati, Stefano Paraboschi, Pierangela Samarati, Controlling Access to XML Document, IEEE INTERNET COMPUTING,
11～12, 2001.
[26] Fabio Simeoni, David Lievens, Richard Connor, Paolo Manghi, Language Bindings to XML, IEEE INTERNET COMPUTING, 1-2, 2003.
[27] Hon Chung MAK, Edmund, Shermann S.M. Chan, Qing Li, XML vs. Object Oriented XML: Motivations, Applications and Performance, Proceedings of the First International Symposium on Cyber Worlds(CW'02), 2002.
[28] E. Damiani, S. De Capitani di Vimercati, S. Paraboschi, P. Samarati, A Fine-Grained Access Control System for XML Documents, ACM Transactions on Information and System Security, Vol. 5, No. 2, 2002.5.
[29] YanIei Diao, Peter M. Fischer, Michael J. Franklin, Raymond To, YFilter: Efficient and Scalable Filtering of XML Documents, Proceedings of 18th International Conference on Data Engineering 2002, 2002.2.
[30] Hao He, Raymond K. Wong, A Role-Based Access Control Model For XML Repositories, First International Conference on Web Information Systems Engineering (WISE'00)-Volume 1, 2000.6.
[31] Emmanuel Pietriga, Jean-Yves Vion-Dury, Vincent Quint, VXT: A Visual Approach to XML Transformations, Proceedings of the 2001 ACM Symposium on Document engineering, 2001.
[32] Pankaj M. Tolani, Jayant R. Haritsa, XGRIND: A Query-friendly XML Compressor, 8th Int'l Conference on Data Engineering, 2002.
[33] Mark Nelson, LZW Data Compression, Dr. Dobbs' Journal, 1989.10.
[34] Weimin Li, XCOMP: AN XML COMPRESSION TOOL, Waterloo 大学硕士论文，2003。
[35] Marc Girardot, Neel Sundaresan, Millau: an encoding format for efficient representation and exchange of XML over the Web.
[36] Dare Obasanjo, 在使用XPath 查询XML文档时应了解和避免的事情，MSDN,http://www.microsoft.com/china/msdn/library/dnexxml/xm106172002.asp.
[37] W3C, What is XSL?, http://www.w3.org/Style/XSL/WhatIsXSL.html.
[38] Jane Fung,解码XML和DTD, IBM develperWorks,http://www-900.ibm.com/developerWorks/cn/xml/x-dtdint/index.shtml#ggviewer-of fsite-nav-13383528.
[39] David Mertz, XML问题#7W3C XML Schema 与文档类型定义(DTD)比较, IBM developerWorks, http://www-900.ibm.com/developerWorks/cn/xml/xml-matters/x-matters7.shtml.
[40] Murdoch Mactaggart,启用XML安全性—XML加密和XML签名简介，IBM developerWorks. http://www-900.ibm.com/developerWorks/cn/xml/s-xmlsec/index.shtml.
[41] XACL FAQ http//www.trl.ibm.com/projects/xml/xacl/xacl-faq.html.
[42] A Brief Introduction to XACML, http://www.oasis-open.org/committees/download.php/2713/Brief Introduction to XACML.html.
[43] 王咏刚，数据压缩技术概论, http://www.contextfree.net/wangyg/index.html.
[44] 王咏刚，数据压缩教程，
http://www.contextfree.net/wangyg/tech/benben/default.htm.
[45] Dan Wahlin,高效交换XML 文档，http://www.fawcette.com/china/XmlFile.aspx?ID=278.
[46] 郝斌，基于角色管理的系统访问控制，http://www-900.ibm.com/developerWorks/cn/security/syscontrol/index.shtml.
[47] David Mertz, XML 问题 #13 XML 和压缩—探索文档的平均信息量，IBM developerWorks,http://www-9OO.ibm.com/developerWorks/cn/xml/x-matters/part13/index.shtml#ggv iewer-offsite-nav-13383528.
[48] David Mertz, XML 问题 #19 XML 和压缩的进一步探讨—块级别压缩和资源负载, IBMdeveloperWorks, http://www-900.ibm.com/developerWorks/cn/xml/x-matters/part19/index.shtm1#ggv iewer-offsite-nav-13383528.
[49] Xalan C++1.7, http://xml.apache.org/xalan-c/.
[50] Xalan-dev mailing list archives, http://marc.theaimsgroup.com/?l=xalan-dev.
[51] apache DOM Programming Guide, http://xml.apache.org/xerces-c/program-dom.html.
[52] Xerces C++2.5.0, http://xml.apache.org/xerces-c/index.html.
[53] XMark-An XML Benchmark Project, http://monetdb.cwi.nl/xml/.
[54] Using Expat,http://www.xml.com/pub/a/1999/09/expat/index.html?page=2.
[55] XCeed, http://www.xceedsoft.com/products/Stream/.
[56] XMill,http://www.research.att.com/sw/tools/xmill/#ggviewer-offsite-nav-13383528.
[57] XGrind,http://sourceforge.net/projects/xgrind/#ggviewer-offsite-nav-13383528.
[58] Millau,http://www9.org/w9cdrom/154.154.htm1#ggviewer-offsite-nav-13383528.
[59] XCDE,http://roquefort.di.unipi.it/-ferrax/xcde/xcdelib.html.
[60] zlib,http://www.gzip.org/zlib/zlib docs.html.
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