Towards effective support of engineering information systems

Existing interfaces to nowadays database systems show to be increasingly unsuitable for the evolving wide spectrum of engineering applications (e.g. CAD/CAM, geographic information management, knowledge-based systems for planning and design, etc.). This is further intensified due to the workstation-oriented processing scheme prevailing in the engineering area. Starting with an architectural approach tailored to this distributed processing concept, we propose the PRIMA-NDBS and its most important interfaces, i.e. the data model and the application/user interface offering effective support of engineering information systems

Object orientation within the PRIMA-NDBS

In the following we wish to highlight the design and implementation concepts of a non-standard database system (NDBS) called PRIMA and its provision for object orientation

DB-Schnittstellen für arbeitsplatzorientierte Ingenieuranwendungen

Die Schnittstellen gegenwärtig verfügbarer Datenbanksysteme erweisen sich als ungeeignet für den Bereich der lngenieuranwendungen. Dies gilt im besonderen, da bei Ingenieuranwendungen eine deutliche Arbeitsplatzorientierung vorherrscht und sie damit häufig auf einer speziellen Mehrrechnerarchitektur aufbauen. Ausgehend von einem Schichtenmodell für sog. Non-Standard-Datenbanksysteme (NDBS) schlagen wir daher eine spezielle Systemarchitektur mit einer entsprechend ausgelegten Datenmodell- und Anwendungsmodellschnittstelle für arbeitsplatzorientierte Ingenieuranwendungen vor

Use of inherent parallelism in database operations

Non-standard applications of database systems (e.g. CAD) are characterized by complex objects and powerful user operations. Units of work decomposed from a single user operation are said to allow for inherent semantic parallelism when they do not conflict with each other at the level of decomposition. Hence, they can be scheduled concurrently. In order to support this processing scheme it is necessary to organize parallel execution by adequate control units. Therefore, client-server processes and nested transactions are applied to hierarchically structure the DBS-operations. On the other hand, the DBS-code itself has to be mapped onto a multiprocessor system to take advantage of multiple processing units

KUNICAD : ein datenbankgestütztes geometrisches Modellierungssystem für Werkstücke

Es wird ein datenbankgestütztes, volumenorientiertes Modellierungssystem für Werkstücke beschrieben, das als Kernalgorithmus für die geometrische Modellierung ein volumenorientiertes Verfahren einsetzt. Zur Unterstützung der graphischen Repräsentation der Werkstücke werden intern zusätzlich Strukturen nach dem Begrenzungsflächenmodell gehalten, die automatisch aus den CSG-Strukturen abgeleitet und nachgeführt werden. Das KUNICAD-System wird durch seine Gesamtarchitektur, seine Benutzerschnittstelle und sein zugrundeliegendes Anwendermodell skizziert. Die Modellierungskomponente wird durch ihre wesentlichsten Aufgaben - die Darstellung der Objekte und ihre Handhabung - beschrieben. Eine objektunterstützende Datenbankschnittstelle wurde nach dem Zusatzebenen-Architekturkonzept auf der Basis eines CODASYL-Datenbanksystems (UDS) entwickelt. Das implementierte System gestattet das Studium von praxistauglichen CAD-Schnittstellen und erlaubt eine detaillierte Analyse des durch die Datenbankverwaltung bedingten Mehraufwands bei CAD-Operationen.A volume-oriented modeling system for solids using a database system for all data management functions is described in detail. It relies on a volumeoriented algorithm for geometric modeling. To support the graphic representation of solids, their boundary representation, automatically derived from CSG structures and maintained, is provided internalty. The KUNICAD system is sketched by its overall architecture, its user interface and the related application model. The modeling component is described by its essential tasks - the representation of objects and their manipulation. Database management functions are enhanced by the development of an object-supporting interface whereby a CODASYL database system (UDS) is extended by an additional layer. The implemented system permits the study of practical CAD interfaces and allows for a detailed analysis of the overhead produced by the database management for CAD operations

Processing and transaction concepts for cooperation of engineering workstations and a database server

A DBMS kernel architecture is proposed for improved DB support of engineering applications running on a cluster of workstations. Using such an approach, part of the DBMS code - an application-specific layer - is allocated close to the corresponding application on a workstation while the kernel code is executed on a central server. Emperical performance results from DB-based engineering applications are reported to justify the chosen DBMS architecture. The paper focuses on design issues of the application layer including server coupling, processing model and application interface. Moreover, a transaction model for long-term database work in a coupled workstation-server environment is investigated in detail

Coupling engineering workstations to a database server

A DBMS kernel architecture is proposed for improved DB support of engineering applications running on a cluster 01 workstations. Using such an approach, part of the DBMS code - an application-specific layer - is allocated close to the corresponding application on a workstation while the kernel code is executed on a central server. Empirical performance results from DB-based engineering applications are reported to justify the chosen DBMS architecture. The paper focuses on design issues of the application layer including server coupling, processing model and application interface. Moreover, a transaction model for long-term database work in a coupled workstation-server environment is investigated in detail