In this paper we extend the XPath data model and query language to include valid time. XPath is a language for specifying locations within an XML document. We extend XPath’s data model by adding to each node a list of disjoint intervals or instants that represents the valid time. The valid time for a node is constrained to be a subset of the valid time for a node’s parent. We extend the XPath q...

The problem of XPath query satisfiability under DTDs (Document Type Definitions) is to decide, given an XPath query p and a DTD D, whether or not there is some document valid with respect to D on which p returns a nonempty result. Recent studies in the literature have shown the problem to be NP-hard or worse for most fragments of XPath. However, in this paper we show that the satisfiability pro...

This paper presents the METAXPath data model and query language. METAXPath extends XPath with support for XML metadata. XPath is a specification language for locations in an XML document. It serves as the basis for XML query languages like XSLT and the XML Query Algebra. The METAXPath data model is a nested XPath tree. Each level of metadata induces a new level of nesting. The data model separa...

The widespreading of XML as a content-description language on the Web requires advanced processing and management techniques for huge XML databases. XPath is a standard language for extracting the specified elements from XML documents, and its efficient support is one of the key issues in the current XML database technology. In this paper, we propose an XPath query transformation method for the...

XPath is a very natural and powerful way to specify locations in XML documents. This paper examines possible generalizations of XPath to allow both locations and paths through generalized labeled directed graphs to be specified. The need for such a path language is driven by work in querying Linguistic Annotations which are in general more complex in structure than XML documents. The result of ...

This work describes a method for processing XPath on a relational back-end that significantly limits the number of SQL joins required, takes advantage of the strengths of modern SQL query processors, exploits XML schema information and has low implementation complexity. The method is based on the splitting of XPath expressions into Primary Path Fragments (PPFs) and their subsequent combination ...

In this paper we consider a powerful mechanism, called Regular XPath, for expressing queries and constraints over XML data, including DTDs and existential path constraints and their negation. Regular XPath extends XPath with binary relations over XML nodes specified by means two-way regular path queries. Our first contribution deals with checking satisfiability of Regular XPath constraints. Whi...

XPath was introduced as the standard language for addressing parts of XML documents, and has been widely adopted by practioners and theoreticaly studied. We aim at building a logical framework for formal study and analysis of XPath and have to face the combinatorial complexity of formal proofs caused by XPath expressive power. We chose the Coq proof assistant and its powerful inductive construc...

XPath is a simple language for navigating an XML-tree and returning a set of answer nodes. The focus in this paper is on the complexity of the containment problem for various fragments of XPath. We restrict attention to the most common XPath expressions which navigate along the child and/or descendant axis. In addition to basic expressions using only node tests and simple predicates, we also co...