6193947
Schema-driven Customization of Web Services
Publisher Summary This chapter discusses schema-driven customization of Web services. Web services are emerging as a standard mean of publishing and accessing data on the Web, by providing a standard XML-based protocol to invoke remote programs over the Web (simple object access protocol (SOAP)), along with a standard language to describe them (web service description language (WSDL)). XML is becoming the universal format for data exchange between applications. Recently, the use of XML documents, where some of the data is given explicitly, while other parts are defined by programs that generate the relevant data, started gaining popularity. This chapter refers to such documents as intensional documents. Materialization is the process of invoking some of the programs included in an XML document and replacing them by their results. The goal of this demonstration is to advocate for the exchange of such intensional XML documents between applications, and to illustrate the new possibilities and the great flexibility they bring to application design.
39011254
Correspondence and Translation for Heterogeneous Data
We presented a specification of the integration of heterogeneous data based on correspondence rules. We showed how a unique specification can served many purposes (including two-way translation) assuming some reasonable restrictions. We claim that the framework and restrictions are acceptable in practice, and in particular one can show that all the document-OODB correspondences/translations of [2, 3] are covered. We are currently working on further substantiating this by more experimentation.
847694
Reasoning about XML update constraints
We introduce in this paper a class of constraints for describing howan XML document can evolve, namely XML update constraints. For these constraints, we study the implication problem, giving algorithms and complexity results for constraints of varying expressive power. Besides classical constraint implication, we also consider an instance-based approach. More precisely, we study implication with respect to a current tree instance, resulting from a series of unknown updates. The main motivation of our work is reasoning about data integrity under update restrictions in contexts where owners may lose control over their data, such as in publishing or exchange.
5096355
Dynamic XML documents with distribution and replication
The advent of XML as a universal exchange format, and of Web services as a basis for distributed computing, has fostered the apparition of a new class of documents: dynamic XML documents. These are XML documents where some data is given explicitly while other parts are given only intensionally by means of embedded calls to web services that can be called to generate the required information. By the sole presence of Web services, dynamic documents already include inherently some form of distributed computation. A higher level of distribution that also allows (fragments of) dynamic documents to be distributed and/or replicated over several sites is highly desirable in today's Web architecture, and in fact is also relevant for regular (non dynamic) documents.The goal of this paper is to study new issues raised by the distribution and replication of dynamic XML data. Our study has originated in the context of the Active XML system [1, 3, 22] but the results are applicable to many other systems supporting dynamic XML data. Starting from a data model and a query language, we describe a complete framework for distributed and replicated dynamic XML documents. We provide a comprehensive cost model for query evaluation and show how it applies to user queries and service calls. Finally, we describe an algorithm that, for a given peer, chooses data and services that the peer should replicate to improve the efficiency of maintaining and querying its dynamic data.
1444961
Compact Labeling Scheme for Ancestor Queries
We consider the following problem. Given a rooted tree $T$, label the nodes of $T$ in the most compact way such that, given the labels of two nodes $u$ and $v$, one can determine in constant time, by looking only at the labels, whether $u$ is ancestor of $v$. The best known labeling scheme is rather straightforward and uses labels of length at most $2\log_2 n$ bits each, where $n$ is the number of nodes in the tree. Our main result in this paper is a labeling scheme with maximum label length $\log_2 n + \Oh(\sqrt{\log n})$. Our motivation for studying this problem is enhancing the performance of web search engines. In the context of this application each indexed document is a tree, and the labels of all trees are maintained in main memory. Therefore even small improvements in the maximum label length are important.
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.
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.
38767
Inferring structure in semistructured data
When dealing with semistructured data such as that available on the Web, it becomes important to infer the inherent structure, both for the user (e.g., to facilitate querying) and for the system (e.g., to optimize access). In this paper, we consider the problem of identifying some underlying structure in large collections of semistructured data. Since we expect the data to be fairly irregular, this structure consists of an approximate classification of objects into a hierarchical collection of types. We propose a notion of a type hierarchy for such data, and outline a method for deriving the type hierarchy, and rules for assigning types to data elements.
140229514
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 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. The research presented here was motivated by the Xyleme project at INRIA, whose objective it to develop a data warehouse for Web XML documents.
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).
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.