see also

White Papers

some in German
STJA99 The Pitfalls of Business Rules and Meta Systems (1999) 
Wolfgang Keller

Background material for a Tutorial at STJA99

Abstract: As people find out that object-orientation and rapid development alone are often not fast enough in order to adapt software to changing environments and ever changing business processes they turn to meta-systems and try to define business rules in a declarative way. This paper discusses an array of typical design flaws and problems in such systems in order to help you avoid the pitfalls described. Most of the pitfalls described in this paper also contain possible ways to refactor a system once you have identified the problem.

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rd_pin.gif (1016 Byte)and don't miss the Tutorial
vaa.gif (1178 Byte) VAA-Handbuch für die Spezifikation fachlicher Anwendungsbausteine (1996)
Wolfgang Keller

Mit diesem Dokument legt der AK-VAA ein einheitliches Handbuch zur Spezifikationsmethodik für die fachlichen Anwendungsbausteine von VAA vor. Spezifikationen bestehen aus fachlichen Übersichtsteilen und eher formalen Modellen, die mit der sog. Sachbearbeitermethode spezifiziert werden.

 rd_pin.gif (1016 Byte)Download (Zipped Handbuch in WinWord)

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sdmklein.gif (1933 Byte) OOrdnung tut not HORA - ein flexibles Dictionary für den objektorientierten Entwicklungsprozeß (1994)
Gero Scholz, Wolfgang Keller

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 rd_pin.gif (1016 Byte)or see Shore - the actual product by sd&m

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  Fehlerbehandlung in großen C++ Projekten
Wolfgang Keller, Dr. Klaus Wagner: Harrt ewig der Volendung, weil wir besseres haben. Die anderen Dinge sind aber teilweise Copyright belastet.

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rd_pin.gif (1016 Byte)For something in pattern form see also ARCUS Pages on Error Handling.

arcuslogoquer.gif (2954 Byte) Object Identifiers for Relational Legacy Data (1995)
Wolfgang Keller

This paper describes problems that you will be confronted with, when trying to build an Object Oriented Data Access Layer for relational legacy data without any alterations of old tables the relational data reengineering problem. This results in very expensive solutions for OID (Object Identifier) handling. We present our current solution, the solutions we have abandoned in a first discussion and we invite others to join our discussion with the purpose to find an elegant solution for the handling of relational legacy data in OODBMS without breaking ODMG'93 user code patterns.This paper does not discuss the overal architecture of an access layer it only discusses the special problems around object identity.

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rd_pin.gif (1016 Byte)see also a later paper on the same topic by some friends

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arcuslogoquer.gif (2954 Byte) Mapping Associations from OODBs to RDBMs (1995)
Wolfgang Keller

This paper describes problems that you will be confronted with, when trying to build an Object Oriented Data Access Layer for relational legacy data without any alterations of old tables the relational data reengineering problem. Mapping associations is one central topic that has to be handled for such an access layer. We present our current solution, the solutions we have abandoned in our discussion and we invite others to join our discussion with the purpose to find an elegant solution for the handling of relational legacy data in OODBMS without breaking ODMG'93 user code patterns. This paper does not discuss the overal architecture of an access layer it only discusses the special problems around relations.

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rd_pin.gif (1016 Byte)See also the pattern papers on object relational access layers