72 CHAPTER 5 Selecting Materialized Views
ing these large tables can consume significant resources. We will focus on the queries
that occur frequently, and also heavily consume disk input/output (I/O). If we have the
result of such a query, then why not save the result to disk, and just read the answer the
next time the query is posed? Materialized views are precalculated results stored on disk.
Quick query response is the goal.
There are two ways that materialized views can be accessed. The first is the brute
force method where the SQL is written to explictly access the view. This method limits
the choices for the query optimizer in selecting other potentially superior query execu-
tion plans perhaps using some of the base tables on which the materialized ...