Mechanism for View Maintenance Under Schema and Data Concurrent Updates
During maintaining the materialized view in the data warehouse, how to efficiently handle the concurrent updates is an important and intractable problem. The paper discusses typical situations that scheme change mixes with data updates concurrently. And the reasons why concurrent updates result in view maintenance anomy are analyzed. Based on the different situations, the corresponding correct strategy is presented. Furthermore, the paper proposes the temporal methods for detecting concurrent updates and related updates under mixing scheme change and data updates. Lastly, an enhanced commit agent is designed for deal with non-orderly commit problem. Thus, the consistency between data warehouse and data source is guaranteed.