what is materilaized views?

>what is materialized views?
is a kind of view, but storing the results like a table. based on the refresh parameters, the data can be updated automatically behind, either fully or with transactional update.

>how its helps in database performance?
materialized views can reduce I/O on the queries (check out query rewrite), doing pre-aggregation.

>why we refresh it?
because the underlying data changes, and unlike a traditional view, the underlying data is not queried, but the stored data.

but view can also store the result like a table if we update any table if we have created a views on it then the changes will reflect in the view.
please explain the below statement in more details

materialized views can reduce I/O on the queries (check out query rewrite), doing pre-aggregation.

could you please explain me the basic difference between views and materialized view.

thanks ..
could you please tell me the difference between view and materialized view.

thanks for your help.

I think one more difference is that we can refresh materialized view and we cant normal view.

one more we can create view only for a particular session.

thanks a lot...