软件学报
軟件學報
연건학보
JOURNAL OF SOFTWARE
2009年
11期
2977-2987
,共11页
路径表达式%XML结构完整性约束%路径蕴涵闭包%子路径%最小化
路徑錶達式%XML結構完整性約束%路徑蘊涵閉包%子路徑%最小化
로경표체식%XML결구완정성약속%로경온함폐포%자로경%최소화
path expression%structural integrity constraint for XML%path implication closure%sub-path%minimization
引入了一个XML结构完整性约束体系.这个体系描述了XML文档中节点或路径之间的5种结构关系,包括路径蕴涵、路径同现、路径互斥、必需性包含和排他性包含.给出了这些结构完整性约束的语法和语义定义,并研究了它们在XML查询优化中的作用.基于子路径的概念,提出了有结构完整性约束的路径表达式的最小化算法.该算法以路径蕴涵闭包为工具,不仅可以删除路径表达式的冗余,还可以识别无效路径表达式.实验结果表明了该算法的正确性和有效性.
引入瞭一箇XML結構完整性約束體繫.這箇體繫描述瞭XML文檔中節點或路徑之間的5種結構關繫,包括路徑蘊涵、路徑同現、路徑互斥、必需性包含和排他性包含.給齣瞭這些結構完整性約束的語法和語義定義,併研究瞭它們在XML查詢優化中的作用.基于子路徑的概唸,提齣瞭有結構完整性約束的路徑錶達式的最小化算法.該算法以路徑蘊涵閉包為工具,不僅可以刪除路徑錶達式的冗餘,還可以識彆無效路徑錶達式.實驗結果錶明瞭該算法的正確性和有效性.
인입료일개XML결구완정성약속체계.저개체계묘술료XML문당중절점혹로경지간적5충결구관계,포괄로경온함、로경동현、로경호척、필수성포함화배타성포함.급출료저사결구완정성약속적어법화어의정의,병연구료타문재XML사순우화중적작용.기우자로경적개념,제출료유결구완정성약속적로경표체식적최소화산법.해산법이로경온함폐포위공구,불부가이산제로경표체식적용여,환가이식별무효로경표체식.실험결과표명료해산법적정학성화유효성.
A system of structural integrity constraints for XML (XSICs) is introduced, which specifies five structural relationships between different paths or nodes in XML documents, including path implication, path cooccurrence, path mutual-exclusion, obligatory inclusion and exclusive inclusion. This paper defines the syntax and semantics of these XSICs, and studies their core role in XML query optimization. Based on the concept of sub-path, this paper proposes an algorithm for minimizing path expression in the presence of XSICs. By using the path implication closure as a tool, the algorithm cannot only effectively eliminate redundant nodes or predicates, but also identify invalid path expressions. Experimental results show the effectiveness and efficiency of the proposed minimization algorithm.