Enriched relationship processing in object-relational database management systems

The authors bring together two important topics of current database research: enhancing the data model by refined relationship semantics and exploiting ORDBMS extensibility to equip the system with new functionality. Regarding the first topic, we introduce a framework to capture diverse semantic characteristics of application-specific relationships. Then, in order to integrate the conceptual extensions with the data model provided by SQL: 1999, the second topic comes into play. Our efforts to realize semantically rich relationships by employing current ORDB technology clearly point out the benefits as well as the shortcomings of its extensibility facilities. Unfortunately, deficiencies still prevail in the OR-infrastructure, since the features specific to the extensions cannot sufficiently be taken into account by DBMS-internal processing such as query optimization, and there are very limited mechanisms for adequately supporting the required properties, e.g., by adjusted index and storage structures as well as suitable operational units of processing.