Data Integration Using Self-Maintainable Views

In this chapter we define the concept of self-maintainable views — these are views that can be maintained using only the contents of the view and the database modifications, but without accessing any of the underlying databases. We derive tight conditions under which a view is self-maintainable, and we give algorithms to self-maintain several types of select-project-join views upon insertions, deletions and updates. Self-maintainability is a desirable property for efficiently maintaining large views in applications where fast response and high availability are important. One example of such an environment is Data warehousing wherein views are used for integrating data from multiple databases.