XML查询处理技术简介周军锋
XML查询处理技术简介 周军锋
数据组织XML: eXtensible Markup Language作用:用于网络数据的表述和交换无结构数据XML文档结构化数据
数据组织 XML:eXtensible Markup Language 作用:用于网络数据的表述和交换 无结构数据 结构化数据 XML文档
数据组织<Root>BOOK<BOOK>NameYearPriceAuthor<Name>XML</Name>XML1999JoeDB2000Mike<Year>1999</Year><Price>20</Price><Author>Joe <Author></BOOK><BOOK><Name>DB</Name><Year>2000</Year><Price>32</Price>Root<Author>Mike<Author>BOOKBOOK</BOOK></Root>NameYearPriceAuthor NameYearPriceAuthorJoeDBXML19992000Mike
数据组织 <Root> <BOOK> <Name> XML </Name> <Year> 1999 </Year> <Price> 20 </Price> <Author> Joe <Author> </BOOK> <BOOK> <Name> DB </Name> <Year> 2000 </Year> <Price> 32 </Price> <Author> Mike <Author> </BOOK> </Root> BOOK DB XML 2000 1999 Mike Joe Name Year Price Author BOOK NameYear Price Author XML 1999 Joe Root BOOK Name Year Price Author DB 2000 Mike
结构化查询RootBOOKBOOKNameYearPriceAuthorNameYearPriceAuthorXML1999DB2000JoeMikeBOOK//XPath: //BOOK[/Name="XML"]Name/XML问题:已知文档结构掌握相关的查询语言大量高效算法
结构化查询 BOOK Name Year Price Author XML 1999 Joe Root BOOK Name Year Price Author DB 2000 Mike . XPath: //BOOK[/Name=“XML”] 问题: 已知文档结构 掌握相关的查询语言 大量高效算法 BOOK Name XML // /
Partial 查询Motivation- schema or structure knowledge is not fullyavailable-Heterogeneous data-Schema evolution
Partial 查询 • Motivation − schema or structure knowledge is not fully available − Heterogeneous data − Schema evolution