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Due to the development of the World Wide Web, the integration of heterogeneous data sources has become a major concern of the database community. Appropriate architectures and query languages have been proposed. Yet, the problem of data conversion which is essential for the development of mediators/wrappers architectures has remained largely unexplored. In(More)
Structured documents (e.g., SGML) can benefit a lot from database support and more specifically from object-oriented database (OODB) management systems. This paper describes a natural mapping from SGML documents into OODB's and a formal extension of two OODB query languages (one SQL-like and the other calculus) in order to deal with SGML document retrieval.(More)
Modern applications (Web portals, digital libraries, etc.) require integrated access to various information sources (from traditional DBMS to semistructured Web repositories), fast deployment and low maintenance cost in a rapidly evolving environment. Because of its flexibility, there is an increasing interest in using XML as a middleware model for such(More)
Many declarative query languages for object oriented oo databases allow nested subqueries This paper contains the rst algebra which is capable of handling arbitrary nested queries and the rst complete classi cation of oo nested queries and the according unnesting strategies For unnesting a two phase approach is used The rst phase called dependency based(More)
that consist in grammars annotated with database programs. To query documents, we introduce an extension of OQL, the ODMG standard query language for object databases. Our extension (named OQL-doc) allows us to query documents without a precise knowledge of their structure using in particular generalized path expressions and pattern matching. This allows us(More)
We show how structured data stored in files can benefit from standard database technology and in particular be queried and updated using database languages. We introduce the notion of structuring schema which consists of a grammar annotated with database programs and of a database schema. We study the translation from structured strings to databases, and(More)
We are interested in defining and querying views in a huge and highly heterogeneous XML repository (Web scale). In this context, view definitions are very large, involving lots of sources, and there is no apparent limitation to their size. This raises interesting problems that we address in the paper: (i) how to distribute views over several machines(More)
The goal of this work is to integrate in a general framework the different query optimization techniques that have been proposed in the object-oriented context. As a first step, we focus essentially on the logical aspect of query optimization. In this paper, we propose a formalism (i) that unifies different rewriting formalisms, (ii) that allows easy and(More)
Electronic commerce is emerging as a major Web-supported application. In this paper we argue that database technology can, and should, provide the backbone for a wide range of such applications. More precisely, we present here the ActiveViews system, which, relaying on an extensive use of database features including views, active rules (triggers), and(More)