Abstract: This Object-Oriented programming system migrates persistent objects when their class declarations are modified. The objects and their class descriptions are persistently stored and the persistent versions of an objects' superclass descriptions are compared to later versions of the objects' superclass descriptions. When a persistent version and a later version of the class description for the object differ, the object is migrated from the persistent version to the later version based on the differences between the two superclass descriptions. Finally, the migrated object is persistently stored with changes in its persistent class description.

Abstract: This system involves an object persistence framework for an object-oriented program which provides a persistent class, data storage class and a data cursor class, that permits specialized implementations of object storage and retrieval with heterogeneous permanent storage systems.

Abstract: In response to the users actions relative to graphical representations of a multiple inheritance concept hierarchy to delete, add or modify the relationships between the various concepts, property declaration, property constraints and relationships therebetween, this system first, recognizes and disambiguates possible semantic incoherance introduced by the changes; second, suggests alternative procedures to ameliorate any perceived incoherence; third, interactively allows an agent (user or machine) to select from one of the alternatives; and fourth, performs the sequence of necessary operations to resolve semantic incoherence in the modified hierarchy.