Incremental materialization of object-oriented views

Abstract

We present an approach to handle incremental materialization of object-oriented views. Queries that define views are implemented as methods that are invoked to compute corresponding views. To avoid computation from scratch each time a view is accessed, we introduce some deferred update algorithms that reflect for a view only related modifications introduced into the database while that view was inactive. A view is updated by considering modifications performed within all classes along the inheritance and class-composition subhierarchies rooted at every class used in deriving that view. To each class, we add a modification list to keep one modification tuple per view dependent on that class. Such a tuple acts as a reference point that marks the start of the next update to the corresponding view.

XML materialized views and schema evolution in VIREX

“…In fact, there are many view related studies that investigate different types of database systems, such as relational and object-oriented databases, e.g., [2][3][4]13,19,21,25,27,40]. Some of the material included in this literature review are not directly related to XML views.…”

“…Alhajj et al [2][3][4] focus on different aspects of view maintenance in object-oriented databases. They [4] show the importance of having a view as primary object in the class hierarchy and define mappings between classes and views.…”

“…The work of Alhajj et al [2] focuses on maintaining materialized views in object-oriented databases by a deferred incremental approach. A model is defined for capturing the definition of base classes and views.…”

“…A materialized view is intended to avoid generating the same result from scratch every time it is to be utilized. The need for handling materialized views has received considerable attention from the database community, e.g., [2,[4][5][6]11,26,32,40,43]. However, there are several properties that must be considered in maintaining views.…”

“…Finally, VIREX supports some schema evolution functions that help in view maintenance and materialization. The approach presented in this paper highly benefits from a view maintenance approach developed for object-oriented databases [2]. The main motivation to go this way is the similarity between the XML schema and the object-oriented hierarchy.…”