In the area of online analytical processing (OLAP), the concept of multidimensional databases is receiving much popularity. Thus, a couple of different multidimensional data models were proposed from the research as well as from the commercial product side, each emphasizing different perspectives. However, very little work has been done investigating guidelines for good schema design within such a multidimensional data model. Based on a logical reconstruction of multidimensional schema design, this paper proposes two multidimensional normal forms. These normal forms define modeling constraints for summary attributes describing the cells within a multidimensional data cube and constraints to model complex dimensional structures appropriately. Multidimensional schemas compliant to these normal forms do not only ensure the validity of analytical computations on the multidimensional database, but also favor an efficient physical database design.

Cooperative problem solving is a joint style of producing and consuming data. Unfortunately, most database mechanisms developed so far; are more appropriate for competitive usage than for a cooperative working style. They mostly adopt an operational point of view which binds data to applications. Data-oriented mechanisms like check-in/out avoid this binding but do not improve synchronization towards concurrent usage of data. Conversations are an application-independent, tight framework for jointly modifying common data. The idea is to create transaction-spanning conversational working stages that organize different contributions instead of serializing accesses. To illustrate the conversation concept, an extended query language with conversational operations is presented.>

In Flexible Manufacturing Systems (FMS) automated production lines are composed of autonomous manufacturing cells connected by tool and part transportation systems. In an ongoing project with a large manufacturer of equipment for numerical and robotic control (NC and RC) it is investigated, how databases can be applied in computer hierarchies for FMSs. To bring databases and FMSs together a conceptual framework is needed at the beginning. In the first part of the paper a FMS is described in some detail. Then an abstraction hierarchy for relevant objects is developed. Finally a conceptual framework for data distribution in a computer hierarchy is specified.

In this paper a method is proposed how to achieve response times of main memory database systems without keeping the whole database in main memory. The method was originally developed for real-time systems in manufacturing automation, but it is applicable in environments where canned transactions interact with databases rather than people performing free transactions. The main idea is to preanalyse canned transactions in order to extract knowledge about their local access behaviour. This knowledge is used by the runtime system of the database when the transaction is started. Concepts for modules doing the preanalysis and the runtime tasks are described in detail. Furthermore a database architecture is developed incorporating these new components.

Designing the conceptual schema of databases is mainly a task of understanding the application world rather than applying a data model to specific situations. In spite of making use of formal terms like functional dependencies, relations etc. experiences in consulting show that a design process should reflect a learning situation and has to start with comprehensible, simplest (i.e. elementary) sentences. A strict constructive approach is outlined guaranteeing that new complex sentences can only be introduced by means of sentences already available to the designer. The structure of the metadatabase is outlined and an implemented design system is described.