Populating and maintaining materialized query tables
After you define a materialized query table, you need to maintain the accuracy of the data in the table.
About this task
This maintenance includes populating the table for the first time and periodically refreshing the data in the table. You need to refresh the data because any changes that are made to the base tables are not automatically reflected in the materialized query table.
The only way to change the data in a system-maintained materialized query table is through the REFRESH TABLE statement. The INSERT, UPDATE, MERGE, TRUNCATE and DELETE statements, and the LOAD utility cannot refer to a system-maintained materialized query table as a target table. Therefore, a system-maintained materialized query table is read-only.
Any view or cursor that is defined on a
system-maintained materialized query table is read-only. However,
for a user-maintained materialized query table, you can alter the
data with the INSERT, UPDATE, and DELETE statements, and the LOAD
utility. 