A Pattern-Based Temporal XML Query Language

The need to store large amount of temporal data in XML documents makes temporal XML document query an interesting and practical challenge. Researchers have proposed various temporal XML query languages with specific data models, however, these languages just extend XPath or XQuery with simple temporal operations, thus lacking both declarativeness and consistency in terms of usability and reasonability. In this paper we introduce TempXTQ, a pattern-based temporal XML query language, with a Set-based Temporal XML (STX) data model which uses hierarchically-grouped data sets to uniformly represent both temporal information and common XML data. TempXTQ deploys various patterns equipped with certain pattern restructuring mechanism to present requests on extracting and constructing temporal XML data. These patterns are hierarchically composed with certain operators like logic connectives, which enables TempXTQ to specify temporal queries consistently with the STX model and declaratively present various kinds of data manipulation requests. We further demonstrate that TempXTQ can present complicated temporal XML queries clearly and efficiently.