53236199
Exchanging Intensional XML Data
XML is becoming the universal format for data exchange between applications. Recently, the emergence of Web services as standard means of publishing and accessing data on the Web introduced a new class of XML documents, which we call intensional documents. These are XML documents where some of the data is given explicitly while other parts are defined only intensionally by means of embedded calls to Web services.When such documents are exchanged between applications, one has the choice to materialize the intensional data (i.e. to invoke the embedded calls) or not, before the document is sent. This choice may be influenced by various parameters, such as performance and security considerations. This paper addresses the problem of guiding this materialization process.We argue that, just like for regular XML data, schemas (ala DTD and XML Schema) may be used to control the exchange of intensional data and, in particular, to determine which data should be materialized before sending a document, and which should not. We formalize the problem and provide algorithms to solve it. We also present an implementation that complies with real life standards for XML data, schemas, and Web services, and is used in the Active XML system [3, 1].
1932947
Representing and querying XML with incomplete information
We study the representation and querying of XML with incomplete information. We consider a simple model for XML data and their DTDs, a very simple query language, and a representation system for incomplete information in the spirit of the representations systems developed by Imielinski and Lipski [1984] for relational databases. In the scenario we consider, the incomplete information about an XML document is continuously enriched by successive queries to the document. We show that our representation system can represent partial information about the source document acquired by successive queries, and that it can be used to intelligently answer new queries. We also consider the impact on complexity of enriching our representation system or query language with additional features. The results suggest that our approach achieves a practically appealing balance between expressiveness and tractability.
1109183
XML Data Integration with Identification
Data integration is the problem of combining data residing at different sources, and providing the user with a virtual view, called global schema, which is independent from the model and the physical origin of the sources. Whereas many data integration systems and theoretical works have been proposed for relational data, not much investigation has been focused yet on XML data integration. Our goal is therefore to address some of its related issues. In particular, we highlight two major issues that emerge in the XML context: (i) the global schema may be characterized by a set of constraints, expressed by means of a DTD and XML integrity constraints, (ii) the concept of node identity requires to introduce semantic criteria to identify nodes coming from different sources. We propose a formal framework for XML data integration systems based on an expressive XML global schema, a set of XML data sources and a set of mappings specified by means of a simple tree language. Then, we define an identification function that aims at globally identifying nodes coming from different sources. Finally, we propose algorithms to answer queries under different assumptions for the mappings.
1233326
Turning the Network into a Database with Active XML
Because of information ubiquity, one observes an important trend towards transferring information management tasks from database systems to networks. We introduce the notion of data ring that can be seen as a network version of a database or a content warehouse. A main goal is to achieve better performance for content management without requiring the acquisition of explicit control over information resources. In this paper, we discuss the main traits of data rings and argue that Active XML provides an appropriate basis for such systems.
52829094
Distributed Information Management with XML and Web Services
XML and Web services are revolutioning the automatic management of distributed information, somewhat in the same way HTML, Web browser and search engines modified human access to world wide information. To illustrate, we present Active XML that is based on embedding Web service calls inside XML documents. We mention two particular applications that take advantage of this new technology and novel research issues in this setting. This paper is based primarily on research at INRIA-Futurs in the Gemo Group, around XML and Web services (in particular, the Xyleme, Active XML and Spin projects).
2598023
Constructing and querying peer-to-peer warehouses of XML resources
We present KADOP, a distributed infrastructure for warehousing XML resources in a peer-to-peer framework. KADOP allows users to build a shared, distributed repository of resources such as XML documents, semantic information about such documents, Web services, and collections of such items. KADOP leverages several existing technologies and models: it uses distributed hash tables as a peer communication layer, and ActiveXML as a model for constructing and querying the resources in the peer network.
9888780
DBGlobe: a service-oriented P2P system for global computing
The challenge of peer-to-peer computing goes beyond simple file sharing. In the DBGlobe project, we view the multitude of peers carrying data and services as a superdatabase. Our goal is to develop a data management system for modeling, indexing and querying data hosted by such massively distributed, autonomous and possibly mobile peers. We employ a service-oriented approach, in that data are encapsulated in services. Direct querying of data is also supported by an XML-based query language. In this paper, we present our research results along the following topics: (a) infrastructure support, including mobile peers and the creation of context-dependent communities, (b) metadata management for services and peers, including location-dependent data, (c) filters for efficiently routing path queries on hierarchical data, and (d) querying using the AXML language that incorporates service calls inside XML documents.
40120481
Peer-to-peer warehousing of XML resources*