Une approche matérialisée basée sur les vues pour l'intégration de documents XML. (A view-based approach to the integration of structured and semi-structured data)

Semi-structured data play an increasing role in the development of the Web through the useof XML. However, the management of semi-structured data poses speci c problems because semi-structured data, contrary to classical databases, do not rely on a prede ned schema. The schemaof a document is contained in the document itself and similar documents may be represented bydi erent schemas. Consequently, the techniques and algorithms used for querying or integratingthis data are more complex than those used for structured data.The objective of our work is the integration of XML data by using the principles of Osiris,a prototype of KB-DBMS, in which views are a central concept. In this system, a family ofobjects is de ned by a hierarchy of views, where a view is de ned by its parent views and itsown attributes and constraints. Osiris belongs to the family of Description Logics ; the minimalview of a family of objects is assimilated to a primitive concept and its other views to de nedconcepts. An object of a family satis es some of its views. For each family of objects, Osirisbuilds a n-dimensional classi cation space by analysing the constraints de ned in all of its views.This space is used for object classi cation and indexation.In this thesis we study the contribution of the main features of Osiris classi cation, index-ation and semantic query optimization to the integration of XML documents. For this purposewe produce a target schema (an abstract XML schema), which represents an Osiris schema ;every document satisfying a source schema (concrete XML schema) is rewritten in terms of thetarget schema before undergoing the extraction of the values of its entities. The objects corre-sponding to these entities are then classi ed and indexed. The Osiris mechanism for semanticquery optimization can then be used to extract the objects of interest of a query.We have realized a prototype, named OSIX (Osiris-based System for the Integration of XMLdocuments) and we have applied it to the integration and interrogation of XML documentssimulating the data of a hospital.