Materialized Query Tables
A materialized query table (MQT) is a table that is defined based on the result of a query of one or more base tables. Prior to v8.1, MQTs required an aggregation operator in their defining SQL and, thus, were called Automatic Summary Tables. The next section describes how MQTs can provide effective performance improvements in a database.
Avoiding Repetitious Calculations
Materialized query tables can help to avoid having to repeat calculations, such as SUMs, for a number of queries that reference the same base table. For a CUSTOMER_ORDER table that stores customer orders for a number of years, the table will grow very large. If the applications run multiple queries on orders for only the year 2002, and only three columns ...
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