Database schemas are often not defined by a single person but by several future users of the database who define their possibly different views on the proposed database schema. These views are collected and integrated during the subsequent design step of view integration. In object-oriented databases, view integration must handle the integration of the structure and the behavior of objects. Whereas integration of object structure has been treated in the realm of semantic data models in the past, integration of object behavior has received little attention so far. Behavior is usually defined at two levels of detail: by activities, which correspond to methods in object-oriented languages, and by object life-cycles, which represent the overall behavior of objects during their life time. This paper presents an approach to integrate object life-cycles in object-oriented database schemas using a notation based on Petri nets. We will introduce different methods of integration depe...

Abstract. Data integration is a significant challenge: relevant data objects are split across multiple information sources, and often owned by different organizations. The sources represent, maintain, and export the information using a variety of formats, interfaces and semantics. This paper addresses the issue of querying distributed data in a large scale context. We present a p2p information mediation framework based on the notion of super-peers, providing a super-peer network. This makes it possible for a super-peer to reach every other peer (data source) in the system, thus realizing the concept of a integrated schema formed from all possible information sources. This is achieved by classifying data sources into domains and creating user profiles for query optimization purposes. 1

Object-oriented database schemas are often defined by several future users of the planned database, where each user defines a schema representing his/her view on the database; the complete database schema is defined by integrating these views in a subsequent step. Behavior of objects is often defined at two levels of detail: at the level of methods and at the level of object life-cycles that represent the overall behavior of objects during their life time. This paper presents an approach to integrate views of object life-cycles to a complete object life-cycle of an object type. We will particularly consider the problem that different users know about parts of the object life-cycle at different levels of detail and often do not consider exactly the same set of entities. 1 1 Introduction Object-oriented database schemas are usually defined in cooperation with potential future users of a database. These users know the entities that should be represented by objects in the data...