Abstract not found

This paper addresses the question of updating relational databases through XML views. Using query trees to capture the notions of selection, projection, nesting, grouping, and heterogeneous sets found throughout most XML query languages, we show how XML views expressed using query trees can be mapped to a set of corresponding relational views. We then show how updates on the XML view are mapped to updates on the corresponding relational views. Existing work on updating relational views can then be leveraged to determine whether or not the relational views are updatable with respect to the relational updates, and if so, to translate the updates to the underlying relational database.

The Semantic Web is based on XML and RDF as its fundamental standards for exchanging and storing information on the World Wide Web. Event-condition-action (ECA) rules are a natural candidate for supporting reactive functionality on XML or RDF repositories. In this paper we describe a language for ECA rules on XML and a prototype implementation of this language. We also discuss some preliminary ideas regarding a language for ECA rules operating on a graph/triple representation of RDF, and we describe the architecture of a distributed deployment of such RDF ECA rules.

Abstract. In the same way as the “static ” Semantic Web deals with data model and language heterogeneity and semantics that lead to RDF and OWL, there is language heterogeneity and the need for a semantical account concerning Web dynamics. Thus, generic rule markup has to bridge these discrepancies, i.e., allow for composition of component languages, retaining their distinguished semantics and making them accessible e.g. for reasoning about rules. In this paper we analyze the basic concepts for a general language for evolution and reactivity in the Semantic Web. We propose an ontology based on the paradigm of Event-Condition-Action (ECA) rules including an XML markup. In this framework, different languages for events (including languages for composite events), conditions (queries and tests) and actions (including complex actions) can be composed to define highlevel rules for describing behavior in the Semantic Web. 1

to automatically react to occurred events. Aside from proprietary approaches for enriching XML with active behavior, the W3C standardized the Document Object Model (DOM) Event Module for the detection of events in XML documents. When using any of these approaches, however, it is often impossible to decide which event to react upon because not a single event but a combination of multiple events, i.e., a composite event determines a situation to react upon. The paper presents the first approach for detecting composite events in XML documents by addressing the peculiarities of XML events which are caused by their hierarchical order in addition to their temporal order. It also provides for the detection of satisfied multiplicity constraints defined by XML schemas. Thereby the approach enables applications operating on XML documents to react to composite events which have richer semantics.

We propose a peer-based architecture that allows for the integration of distributed data and web services. It relies on a language, Active XML, where (1) documents embed calls to web services that are used to enrich them, and (2) new web services may be defined by XQuery queries on such active documents. Embedding calls to functions or even to web services inside data is not a new idea. Our contribution, however, is turning them into a powerful tool for data and services integration. In particular, the language includes linguistic features to control the timing of service call activations. Various scenarios are captured, such as mediation, data warehousing, and distributed computation. A first prototype is described.

A widely acknowledged obstacle for realizing the vision of the Semantic Web is the inability of many current Semantic Web approaches to cope with data available in such diverging representation formalisms as XML, RDF, or Topic Maps. A common query language is the first step to allow transparent access to data in any of these formats. To further the understanding of the requirements and approaches proposed for query languages in the conventional as well as the Semantic Web, this report surveys a large number of query languages for accessing XML, RDF, or Topic Maps. This is the first systematic survey to consider query languages from all these areas. From the detailed survey of these query languages, a common classification scheme is derived that is useful for understanding and differentiating languages within and among all three areas.

XML is a now a dominant standard for storing and exchanging information. With its increasing use in areas such asdatawarehousing and e-commerce, there is a rapidly growing need for rule-based technology to support reactive functionality on XML repositories. Eventcondition-action (ECA) rules automatically perform actions in response to events and are a natural facility to support such functionality. In this paper, we study ECA rules in the context of XML data. We de ne a simple language for specifying ECA rules on XML repositories. The language is illustrated by means of some examples, and its syntax and semantics are then speci ed more formally. We theninvestigate methods for analysing and optimising these ECA rules, a task which has added complexity in this XML setting compared with conventional active databases.

Abstract. In this paper we define the basic concepts for a general language for evolution and reactivity in the Semantic Web. We do this by exposing an UML model that specifies an ontology for the language. The proposed language is based on Event-Condition-Action rules, where different languages for events (including languages for composite events), for conditions (queries) and actions (including complex actions) may be composed, this way catering for language heterogeneity (besides heterogeneity on the data-model) that we think is essential for dealing with evolution and reactivity in the Semantic Web. 1

Abstract. Reactive rules are used for programming rule-based, reactive systems, which have the ability to detect events and respond to them automatically in a timely manner. Such systems are needed on the Web for bridging the gap between the existing, passive Web, where data sources can only be accessed to obtain information, and the dynamic Web, where data sources are enriched with reactive behavior. This paper presents two possible approaches to programming rule-based, reactive systems. They are based on different kinds of reactive rules, namely Event-Condition-Action rules and production rules. Concrete reactive languages of both kinds are used to exemplify these programming paradigms. Finally the similarities and differences between these two paradigms are studied. 1