62 results about "Xpath expression" patented technology

A method for using pre-computed information stored in auxiliary structures to speed up processing of expensive queries on hierarchical documents such as XML documents being queried using XPath. The invention defines a taxonomy of such structures such as indexes and materialized views for storing pre-computed XPath results (PXRs), determines what portion of the query can be evaluated by the structures, and computes the compensation for the results generated by the structures. The invention detects all structures applicable to the query and rewrites the query to use such structures, speeding up the performance of the queries. The invention identifies the matching structures by detecting containment mappings between XPath expressions in the query and the structure. The invention also includes a new representation for XPath expressions that is rich enough to express all features of XPath.

The invention relates to a system and a method for self-adaptively locating dynamic web page elements. The system comprises an XPath generalizer and an enhanced XPath analyzing engine, wherein the XPath generalizer is used for gradually generalizing a complete XPath expression of the web page elements based on an HTML knowledge database for describing the importance of the degree of association and the attribute of an HTML label; and the enhanced XPath analyzing engine is used for searching the web page elements in an HTML DOM tree of a target web page through the generalized XPath expression. The invention ensures that a needed Web content can be located on the basis of the XPath in spite of the change of various web page contents in a dynamic web page through combining the HTML knowledge database.

A system for visually generating query files comprises a file model construction module for modifying the content of a webpage opened via accessing the network by a user into an XML file object model which complies with XML grammar specification and is a standard W3C file object model; a visual editing module for presenting the webpage as a visual and editable base assembly; an XPath expression generation module for analyzing the base assembly selected by the user on the editable webpage and generating an XPath expression according to the position of the base assembly in the XML file object model; and a query file combination module for combining a query file meeting an Xquery standard according to the position relationship of each generated XPath expression in the XML file object model. The invention also provides a method for visually generating query files. The invention enables the users to visually select the extract content according to requirements, and is able to automatically analyze the selected content to generate the XPath expressions and to combine the XPath expressions into a query file.

An apparatus, system, and method are disclosed for optimization of XPath expressions in a database management system configured to accept XML queries. Operations of the method include receiving an XQuery representation and partitioning XPath expressions within the XQuery representation into a plurality of XPath expression clusters. The XPath expression clusters may comprise one or more XPath expressions and those in each cluster may operate on a common document. Furthermore, the XPath expressions in each cluster are hierarchically related to each other such that branch nodes of the cluster are executable independent of nodes in other XPath expression clusters. The method also defines merging the one or more XPath expressions into one or more expression trees for each XPath expression cluster. The method generates one or more query execution plans from the one or more XPath expression blocks. The method includes, for each query execution plan, splitting each of the XPath expression blocks into one or more ordered fragments. The method determines a cardinality according to database statistics and an execution cost for each XPath expression block within each query execution plan. Finally, the method determines an aggregate cardinality for each query execution plan and an aggregate execution cost for each query execution plan. Therefore, an XQuery may be optimized at both the global XQuery and local XPath expression block level, improving performance and reducing overhead.

A method and system for evaluating a path query are disclosed. The path query corresponds to a query tree including a plurality of query nodes. At least one query node corresponds to at least one predicate and is at a level. The predicate(s) are evaluated for previous query node(s). The method and system include scanning data nodes of a document and determining if the data nodes match the query nodes. The method and system also include placing data related to the data node in match stacks corresponding to matched query nodes. The data for the query node(s) include attribute(s) corresponding to the predicate(s). The method and system further include propagating a matching of the at least one query node backward to a matching of the at least one previous query node.

An XML Extractor that extracts XML data from streamed input based on registered XPaths is provided. XPaths and associated content handlers instances are registered at runtime with the XML Extractor. The XML Extractor receives streaming input that represents XML data at a stream-based parser, and evaluates the received input against the registered XPaths expression. In response to detecting that the received streaming input includes an XPath that matches a registered XPath expression, the XML Extractor generates output to the content handler associated with the matching registered XPath expression.