Extending the relational algebra to capture complex objects

An important direction in database research for non-standard applications (e.g. engineering or design applications) deals with adequate support for complex objects. Without doubt, the provision of network structures and shared subobjects as well as support for dynamic object definition and appropriate manipulation facilities is urgently needed for natural and accurate modeling as well as for efficient processing of the applications' objects. These concepts are the major concern of the molecule-atom data model (MAD model) and its molecule algebra which is introduced in this paper. They make the model stand out compared to the relational model and even to models limited to hierarchical and statically defined complex objects. By means of the molecule algebra a precise and complete specification of one conceivable kind of complex object processing and its inherent semantics is provided. Furthermore, this algebra is used as a sound basis to express the semantics of the high level query language MOL (molecule query language) that is able to deal with complex objects in a descriptive manner

PRIMA : a DBMS prototype supporting engineering applications

The design of the Molecule-Atom Data model, aimed at the effective support of engineering applications, is justified and described with its essential properties and features. MAD offers direct and symmetric management of network structures and recursiveness, dynamic object definition and object handling allowing for both vertical and horizontal access. Its prototype implementation PRIMA is discussed using a multi-level model for the DBMS architecture. Our DBMS kernel provides a variety of access path structures, tuning mechanisms, and performance enhancements transparent at the data model interface. PRIMA is assumed to be used in different run-time environments including workstation coupling and multi-processor systems. In particular, it serves as a research vehicle to investigate the exploitation of "semantic parallelism" in single user operations

Towards a unified view of design data and knowledge representation

Adequate information modeling in non-standard application areas (e.g. engineering applications such as CAD/CAM, VLSI design or knowledgebased applications) requires the abstraction concepts of classification, aggregation, generalization, and association. The Molecule-Atom Data model (MAD) designed for the effective support of such an information model is justified and described with its essential properties and features. MAD offers dynamic object definition and object handling, based on direct and symmetric management of network structures and recursiveness. These generic mechanisms can be used to map the above mentioned abstraction concepts in a straight-forward manner. Thus, the mapping of a wide variety of semantic and object-oriented modeling constructs, including complex objects with shared subobjects, becomes feasible. All these concepts are illustrated by means of some vivid examples taken from the areas of CAD/CAM and knowledge-based applications

Integrated persistent object manager (IPOM) : a model to support persistence and data sharing in object-oriented database systems

Computer Scienc