XQuery-based query engine system

Abstract

The invention discloses an XQuery-based query engine system comprising a mediator and a wrapper. The mediator comprises a lexical analysis module, a grammar analysis module, a normalization module, aquery decomposition module and a result processing module, wherein the lexical analysis module breaks the XQuery statement into a token carrying an attribute; the grammar analysis module organizes thetoken into an abstract syntax tree based on an XQuery grammar specification; the normalization module arranges the syntax tree to form a well-formed syntax tree; the query decomposition module traverses the syntax tree, generates a subquery with respect to an underlaying data source and transfers corresponding wrappers; and the result processing module receives a query result transmitted by the wrapper and returns the query result to a user in the form of XML. The wrapper comprises a relation-type data source wrapper and an XML data source wrapper, and receives the XQuery subquery which is transmitted from the mediator and converted into query language supported by the data source for underlaying data source query, and the final result is reconstructed into XML format and transmitted to the result processing module. The invention improves the query efficiency, ensures favorable structure of the query clause constructed by normalization of the abstract syntax tree and enhances the readability.

Description

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AI Technical Summary

Benefits of technology

This technology helps analyze large amounts of complex queries more efficiently than previous methods like analyzing SQL commands alone or performing statistical processing on them. It also allows users to easily extract specific types of values that may have similar properties but differed only slightly between two sources without repeating these operations again. Overall this improvement enables faster searching capabilities while maintaining accuracy.

Problems solved by technology

Technological Problem addressed in this patented technical solution describes how current XML search tools are unable to handle both structural complexity and richer types of data without sacrificing efficiency when analyzing them individually.

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