The role of polymorphic reuse mechanisms in schema evolution in an object-oriented database

Abstract

A seamless approach to the incremental design and reuse of object-oriented methods and query specifications is presented. We argue for avoiding or minimizing the effort required for manually reprogramming methods and queries due to schema modifications, and demonstrate how the role of polymorphic reuse mechanisms is exploited for enhancing the adaptiveness of database programs against schema evolution in an object-oriented database. The salient features of our approach are the use of propagation patterns and a mechanism for propagation pattern refinement. Propagation patterns are employed as an interesting specification formalism for modeling operational requirements. They encourage the reuse of operational specifications against the structural modification of an object-oriented schema. Propagation pattern refinement is suited for the specification of reusable operational modules. It promotes the reusability of propagation patterns toward the operational requirement changes. This approach has a formal basis and emphasizes structural derivation of specifications. The main innovations are in raising the level of abstraction for behavioral schema design, and for making possible the derivation of operational semantics from structural specifications. As a result, both the modularity and reusability of object-oriented schemas are increased.

A Survey of Managing the Evolution of Data Warehouses

“…They can be categorized as sup-porting schema and data evolution as well as supporting versioning. In the first category, e.g., (Ferrandina et al, 1995;Liu et al, 1997;Tresh, 1991), a database evolution is implemented by schema updates and transformations of objects according to the definition of a new schema. In versioning approaches a database manages and stores: (1) multiple versions of objects, e.g., (Abdessalem & Jomier, 1997;Agrawal et al, 1991;Cellary & Jomier, 1990;Sciore, 1994), (2) multiple versions of data structures (classes or schemas), e.g., (Abiteboul & Santos, 1995;Grandi, 2004;Liu et al, 2005), and (3) versions of both classes and objects, e.g., (Andonoff et al, 1995;Bellosta, Wrembel, & Jomier, 1995;Cellary, Jomier, & Koszlajda, 1991;Matos Galante et al, 2005;Peters & Özsu, 1997).…”