Engineering the object-relation database model in O-Raid

Abstract

Raid is a distributed database system based on the relational model. O-Raid is an extension of the Raid system and will support complex data objects. The design of O-Raid is evolutionary and retains all features of relational data base systems and those of a general purpose object-oriented programming language. O-Raid has several novel properties. Objects, classes, and inheritance are supported together with a predicate-based relational query language. O-Raid objects are compatible with C++ objects and may be read and manipulated by a C++ program without any “impedance mismatch”. Relations and columns within relations may themselves be treated as objects with associated variables and methods. Relations may contain heterogeneous objects, that is, objects of more than one class in a certain column, which can individually evolve by being reclassified. Special facilities are provided to reduce the data search in a relation containing complex objects. The implementation of O-Raid extends the implementation of an existing distributed relational system called Raid.