The COCOON model was intended to extend the concepts of relational database management systems (DBMSs) beyond nested relational to object-oriented ones. Key characteristics of COCOON and its database language COOL are: generic, set-oriented query and update operators similar to relational algebra and SQL updates, respectively; object-preserving semantics of query operators, which allows for the definition of updatable views; update operations that keep model-inherent integrity constraints consistent; a separation of the two aspects of programming language "classes": type vs. collection; predicative description of collections, similar to "defined concepts" in KL-One-like knowledge representation languages; automatic classification of objects and views (positioning in the class hierarchy). This report gives a comprehensive introduction to the COCOON model and its language COOL as well as a formal definition. Our formalization uses denotational semantics, a popular technique in programming...

. In this paper, we address the problem of supporting more flexibility on the schema of object-oriented databases. We describe a general framework based on an object-oriented data model, where three levels of objects are distinguished: data objects, schema objects, and metaschema objects. We discuss the prerequisites for applying the query and update operations of an object algebra uniformly on all three levels. As a sample application of the framework, we focus on database evolution, that is, realizing incremental changes to the database schema and their propagation to data instances. We show, how each schema update of a given taxonomy is realized by direct updating of schema objects, and how this approach can be used to build a complete tool for database evolution. 1 Introduction There is an increasing need for database evolution facilities, offering more flexibility on the logical structure of object-oriented databases (OODBs). On the one hand, schema evolution is the basic prereq...

. This paper describes the database algebra QAL which serves as the logical algebra in the query execution system of the Distributed Object Kernel #25#. QAL is based on the concepts of the early functional query languages. It provides a simple functional semantics of the language and the means to express complex queries in a step-by-step manner. The operations of QAL are designed to allow simple and e#cient manipulation of objects having rich classi#cation structure, complex hierarchical or network structure. The expressivepower of QAL is presented through a case-study consisting of a comprehensive set of examples of queries which manipulate complex objects. 1 Introduction Database management systems are employed for storing data in many novel computer applications ranging from computer aided design, process control and computer integrated manufacturing to software engineering, multimedia and Internet applications. Novel demands for the representation and manipulation of th...

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. The data management in the various components of CIM systems is still realized by individual databases where communication between the components is established via interfaces such as STEP. More efficiency, however, is achieved by an integrated approach which is based on an objectoriented database system. This would allow an integrated data management that avoids data redundancy and inconsistencies, and supports all kind of complex structured data. In this talk the requirements for an integrated and distributed data management are discussed. 1 Introduction The situation in companies, especially in those with computer aided manufacturing (CIM), becomes more and more difficult with respect to data management. The difficulty increases with the amount of the data arizing there and with their diversity. These problems are mainly a consequence of incompatible data management systems used in different divisions of the company. Obviously, this incompatibility complicates communication betw...