Recent work on XPath evaluation has produced efficient relational index structures for maintaining and querying XML through a DBMS. Built on top of an relational encoding, named the XPath Accelerator, this thesis takes a closer look at its utilization within the scope of query processing. Basic XPath operations, such as axis steps and simple node tests, remain in the focus of the study. Appropr...

Scala combines the functional and object-oriented paradigms and is good at supporting embedded domain-specific languages. Scala presents therefore an opportunity for designing a new kind of query-language that belongs to the family of XPath-like query-languages, for querying semistructured data that is stored within internal memory. In the terminology of XPath, a relation between the nodes of a...

Linguistic research and language technology development employ large repositories of ordered trees. XML, a standard ordered tree model, and XPath, its associated language, are natural choices for linguistic data storage and queries. However, several important expressive features required for linguistic queries are missing in XPath. In this paper, we motivate and illustrate these features with a...

Generally, most Web applications use relational databases to store and retrieve information. But, the growing acceptance of XML technologies for documents it is logical that security should be integrated with XML solutions. In a web application, an improper user inputs is a main cause for a wide variety of attacks. XML Path or XPath language is used for querying information from the nodes of an...

Applications of description logics (DLs) such as OWL 2 and ontology-based data access (OBDA) require understanding of how to pose database queries over DL knowledge bases. While there have been many studies regarding traditional relational query formalisms such as conjunctive queries and their extensions, little attention has been paid to graph database queries, despite the fact that graph data...

This paper is about the W3C standard node-addressing language for XML documents, called XPath. XPath is still under development. Version 2.0 appeared in 2001 while the theoretical foundations of Version 1.0 (dating from 1998) are still being widely studied. The paper aims at bringing XPath to a “stable fixed point” in its development: a version which is expressively complete, still manageable c...

XML’s rapid adoption as the data representation standard in web based systems is increasing the interest in applying XML query languages (as XPath) to access XML repositories. This technology entails new challenges related to testing, mainly derived from the hierarchical data representation in XML documents and the expressiveness of the query language. In this paper, we present a technique for ...

We study the satisfiability problem for XPath over XML documents of bounded depth. We define two parameters, called match width and braid width, that assign a number to any class of documents. We show that for all k, satisfiability for XPath restricted to bounded depth documents with match width at most k is decidable; and that XPath is undecidable on any class of documents with unbounded braid...

Transaction time is the time of database transactions that create, modify, or destroy facts. It is used to record when facts exist in a database. Accounting for transaction time is essential to supporting audit queries that delve into past database states and differential queries that pinpoint differences between two states. In a web context, transaction time is a problematic concept because th...