A Formal Definition of Selection Operations that Extend Xquery with Interactive Query Construction

XQuery is the standard language for querying XML documents using structural and content restrictions. XQuery is being complemented with a Full-Text language to perform operations on text treating it as a sequence of words, units of punctuation, and spaces. Due to the complex nature of XQuery structured queries, an extension to XQuery was informally proposed to allow for the selection of the interesting subset of elements from each intermediate result of a query. Intermediate results are, thus, available during the construction of the query, which helps the user in building a query to retrieve the desired result. In this paper, we formally define selection operations by extending XQuery grammar and defining new functions. These definitions will be used to build a processing system. The system should be incremental such that, after changing a query, only the operations depending on the changes are computed.