Efficient evaluation of partial path queries over a XML compact storage structure

XML has become an industry standard for data representation and exchange of voluminous data among heterogeneous sources in a distributed environment. There are many ways to query a XML database. Some of the commonly used query languages are Xpath, Xquery, etc. In order to query a XML database, the users should have a proper knowledge of the XML database structure as well as the syntax of the query language that is used. If the users have only partial knowledge of the XML database and are not aware of query languages, partial path query language which was introduced recently can be used. Partial path queries are a subclass of XPath queries. Three algorithms such as Index Path, Partial MJ and Partial Path Stack were implemented over an index streaming model in order to retrieve all path solutions for the partial path query. The storage space required for the index streaming model is large and also the process of evaluating the partial path query using the existing algorithms is complex. To overcome these problems, the PQUICX (Partial Path Pattern Queries over QUICX) algorithm is proposed in this paper. The proposed algorithm evaluates partial path queries over a compact XML storage structure, QUICX (Query and Update Support for Indexed and Compressed XML). Partial path queries are evaluated using the meta table of the QUICX. The possible path solutions are retrieved by the method of path and relationship (parent/child-ancestor/descendant) checking. Also users can retrieve values for the path solutions from the containers of the QUICX. PQUICX algorithm has proved to be efficient in terms of memory requirements and execution time of the query as well.