Study And Implementation Of View Incremental Computation Method In Information System

The incremental maintenance method is usually used to resolve the materialized view maintenance problem. So, view incremental computation is the key link of materialized view maintenance and many other relevant problems in materialized view.In the paper, the method of view incremental computation is mainly studied and implemented in the information integrated environment, so that the view increment will be computed correctly and efficiently. The contribution of the paper is about two aspects:I In the process of view increment computation, the time of base table is different and unattached, so the result of view increment computation will be incorrect. In order to solve the problem, new view computation method is proposed. This method used the base table and incremental table which saved in the database to compensate the discrepancy evocable by the time of view increment computation and the update time of base table. So that correct increment query result is guaranteed.II This paper uses the primary key and referential integrity constraints between base tables to simplify the view computation expression, so that time to access base table is reduced and the time of view increment computation is cut down too. The main idea of the method is:when the primary key and referential integrity constraints is exist in the base table, some increment tupelos which is not relevant to the result can be omission, as a result the amount of increment tupelos is reduced.