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Materialized views designed to speed up queries by storing data from queries in a pre-joined, pre-summarized format. Unlike traditional view ,which is merely stored in the data dictionary as a select statement that is executed when the view is accessed.
A materialized view stores the physical result of the view in its own segment, separate and distinct from the underlying table on which the view is based. The segment can be stored in its own tablespace and can be indexed and partitioned.
Materialized views are intended primarily for use in data warehouse and decision support system where large volumes of data are accessed and summarized using queries.
It also should be refreshed and can be used for query rewrite but you'd probably need dimensions for that to work, and the parameter QUERY_REWRITE_ENABLED set to true.
The refresh can be fast or complete but not always fast works, that's why FORCE can be used.
So.... short description of MVIEWS is really something like shiny night