Integrity maintenance in a heterogeneous engineering database environment

摘要

Integrity maintenance is essential in integrated engineering information systems because the behaviour of the whole system becomes unpredictable unless the integrity of the shared data is properly maintained. However, validation of integrity is often very expensive because it requires lots of cross references of entity instances of the same type or different types, which should be retrieved from database systems in a shared database environment. One of the goals of this work is to minimize the number of database accesses in validating a set of integrity constraints. A heterogeneous database environment is built using EXPRESS as a global schema language. EXPRESS is an international standard information modelling language which was developed for STEP (STandard for the Exchange of Product data). Based on a set of database interface functions, evaluation sequences are determined by analysing the data dependencies among database accesses required for integrity validation.