I. Schmitt and G. Saake. Schema Integration and View Generation by Resolving Intensional and Extensional Overlappings. In K. Yetongnon and S. Hariri, editors, Proc. of the 9th ISCA Int. Conf. on Parallel and Distributed Computing Systems (PDCS'96), Dijon, France, September  Home/Search   Document Not in Database   Summary   Related Articles   Check

....schema integration, although this is a possibility frequently used. We call this the bottom up strategy. Another approach is the top down strategy: The bottom up approach builds federations starting from the information resources towards the global schema, using a database integration method ([17], 16] 10] The structure of the federated schema depends directly on the integrated export schemas and the integration method used. The top down approach builds federations starting from a global schema determined by the information needs of the global information system. This involves a ....

I. Schmitt, G. Saake, Schema integration and view generation by resolving intensional and extensional overlappings, in: K. Yetongnon, S. Hariri (eds.), Proc. 9th ICSA Int. Conf. on Parallel and Distributed Computing Systems (PCDS'96), pp. 751-758, Sep. 1996.

....database is not new. YLCB96] for example, uses this technique to generate a class hierarchy depending on an intensional analysis. In contrast to our approach, however, YLCB96] does not consider extensional relationships and is therefore not useful for schema integration. In [SS96a, SS96b, SC97, SS98] we described how to decompose class extensions for schema integration. This decomposition enables us to use mechanisms of formal concept analysis for schema integration. Our improved algorithm was firstly published in [SS98] Query languages supporting the integration of ....

I. Schmitt and G. Saake. Schema Integration and View Generation by Resolving Intensional and Extensional Overlappings. In K. Yetongnon and S. Hariri, editors, Proc. of the 9th ISCA Int. Conf. on Parallel and Distributed Computing Systems (PDCS'96), Dijon, France, September

....semantical overlappings by introducing generalized classes (upward inheritance) e.g. RPRG94, GCS95] That is, the original inheritance hierarchies are subhierarchies of the resulting merged hierarchy. Henceforth, the resulting hierarchy can become unnecessarily complex. We demonstrated that in [SS96b] Most of the proposed schema integration techniques including view integration techniques (e.g. MNE88, NEL86, SP94] are based on a data model similar to the ER model extended by subtype relationships. They take over the inheritance hierarchies from the local to the integrated schema level and ....

....They take over the inheritance hierarchies from the local to the integrated schema level and adapt them to each other by adding new sub 2 or superclasses or deleting existing classes. In contrast to these approaches, we decompose overlapping class extensions into base extensions (cf. SS96b, SS96a] and use algorithms known from the theory of concept lattices [Wil92] The new aspect proposed in this work is that we combine this theory with schema integration and extensional decompositions. We mean here with the extension of a class a set of possible objects. Such extensions are ....

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I. Schmitt and G. Saake. Schema Integration and View Generation by Resolving Intensional and Extensional Overlappings. In K. Yetongnon and S. Hariri, editors, Proc. of the 9th ISCA Int. Conf. on Parallel and Distributed Computing Systems (PDCS'96), Dijon, France, pages 751--758, September 1996.

....1 Introduction Schema integration [1] is one of the central issues in logically integrating database systems [6] Schema integration aims at deriving an integrated schema which is a virtual view on all database classes to be integrated. Traditionally, all existing schema integration methods, e.g. [4, 7, 3, 2, 5], assume that the database designer as integrator is an expert of the application domain who has complete knowledge about the semantics of the schemata to be integrated. Thus, the database designer should be able to exactly define the extensional relationship between two classes of different ....

I. Schmitt, G. Saake. Schema Integration and View Generation by Resolving Intensional and Extensional Overlappings. In [8], pp. 751--758.

.... is a This work was partly supported by the German Federal State Sachsen Anhalt under grant number FKZ 1987A 0025 ( Federating heterogeneous data base systems and local data management components for global integrity maintenance ) subset of another one (cf. e.g. SPD92] As showed in [SS96a, SS96b] pairwise comparison of class extensions is not always sufficient because not all pieces of information necessary for an adequate integration can be found in that way. Instead, all class extension must be considered at the same time. The result of such an analysis can be presented in a graphical ....

I. Schmitt and G. Saake. Schema Integration and View Generation by Resolving Intensional and Extensional Overlappings. In K. Yetongnon and S. Hariri, editors, Proc. of the 9th ISCA Int. Conf. on Parallel and Distributed Computing Systems (PDCS'96), Dijon, France, pages 751--758, September 1996.

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