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NSPARQL: RDF的一种导航语言

NSPARQL: A Navigational Language for RDF
课程网址: http://videolectures.net/iswc08_perez_nsparql/  
主讲教师: Jorge Pérez
开课单位: 智利天主教大学
开课时间: 2008-11-24
课程语种: 英语
中文简介:
导航特性在很大程度上被认为是图形数据库查询语言的基础。这一事实促使一些作者提出具有导航功能的RDF查询语言。特别是，我们在前一篇文章中已经讨论过嵌套正则表达式适合导航RDF数据，并且我们已经为RDF提出了nSPARQL查询语言，该语言使用嵌套正则表达式作为构建块。在本文中，我们研究了nSPARQL的一些基本性质，涉及到评价的表达性和复杂性。在表达性方面，我们展示了nSPARQL具有足够的表达能力，可以通过直接遍历输入图来回答考虑到RDFS词汇表的语义的查询。我们也证明了 为了得到最后一个结果，嵌套是必要的，我们研究了嵌套正则表达式和SPARQL操作符组合的表达性。关于求值的复杂性，证明了在RDF图G上嵌套正则表达式E的求值可以在O(|G|·|E|)时间内计算。
课程简介: Navigational features have been largely recognized as fundamental for graph database query languages. This fact has motivated several authors to propose RDF query languages with navigational capabilities. In particular, we have argued in a previous paper that nested regular expressions are appropriate to navigate RDF data, and we have proposed the nSPARQL query language for RDF, that uses nested regular expressions as building blocks. In this paper, we study some of the fundamental properties of nSPARQL concerning expressiveness and complexity of evaluation. Regarding expressiveness, we show that nSPARQL is expressive enough to answer queries considering the semantics of the RDFS vocabulary by directly traversing the input graph. We also show that nesting is necessary to obtain this last result, and we study the expressiveness of the combination of nested regular expressions and SPARQL operators. Regarding complexity of evaluation, we prove that the evaluation of a nested regular expression E over an RDF graph G can be computed in time O(|G| · |E|).
关 键 词: 导航语言; NSPARQL; 图形数据; 数据库查询; 导航功能; 嵌套正则表达式; 构建魔块; 遍历输入图形
课程来源: 视频讲座网
最后编审: 2019-05-26：cwx
阅读次数: 80

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