EFFICIENT VIEW MAINTENANCE IN MULTIDATABASE

Outjoin is one of the most frequently used operations for creating global view in multidatabase, but it makes multidatabase’view maintenance more difficult. Most of the existing view maintenance algorithms only consider the views defined by select project join （SPJ） queries. Once the view is created by outjoin, those existing algorithms may fail in view maintenance. In this paper a new view maintenance algorithm is introduced, which can handle view involving outjoin, regular join, and data inconsistency. Moreover, the maintenance mechanism minimizes the number of the queries that need to be sent to the local database systems for view maintenance, which is an efficient way to make the multidatabase system more efficient.