Main Differences between Views and Materialized Views in Oracle

 A view and a materialized view are quite different, although they behave the same to the end-user, in the sence that they look like a table.  The main differences between a view and a materialized view include:

View:  Unike a materialized view, a view is always constructed at runtime, and the tables and joined and aggregations made every time the view is invoked.  A view is also useful for hiding "senisitive" data columns.

Materialized View:  Unlike a view, a materialized view has a concrete existance, in the sence that the tables are pre-joined and aggreations made and the results of the query are stored on disk.  Materialized views also differ from views because they are "redundant", being copied from the base tables. and hence, they need a refresh mechanism.