PRACTIC - A CONCURRENT OBJECT DATA MODEL FOR A PARALLEL OBJECT-ORIENTED DATABASE SYSTEM

A concurrent object data model for a parallel object-oriented database system, named PRACTIC, and its abstract machine are presented. PRACTI C means PaRallel ACTIve Classes and is based on the vertical partition ing arid concurrent management of the database schema classes and meta classes, which are collectively called active objects. Active objects are permanent processes in memory that encapsulate their definitions, methods, and management procedures. Semiactive and passive objects exi st to realize abstract classes and instances (the actual data), respec tively. The? object model gives rise to a query/method execution model that provides parallelism on all levels of the instantiation hierarch y. The abstract PRACTIC machine directly maps the model to a MIMD mach ine. The performance of one Of the proposed parallel query/method exec ution schemes is measured by simulation on the abstract machine.