What is the use of a materialized view?

I created a materialized view as follows

Create materialized view xxx
tablespace sagar_test
refresh complete
start with sysdate
next sysdate+1
enable query rewrite
as
select *
from ab


Then I inserted two records in the table ab. But these two records are not updated in view xxx. How to update these two records ?

A materialized view is a database object that contains the results of a query. They are local copies of data located remotely, or are used to create summary tables based on aggregations of a table's data. Materialized views, which store data based on remote tables are also, know as snapshots.

A materialized view can query tables, views, and other materialized views. Collectively these are called master tables (a replication term) or detail tables (a data warehouse term).

For replication purposes, materialized views allow you to maintain copies of remote data on your local node. These copies are read-only. If you want to update the local copies, you have to use the Advanced Replication feature. You can select data from a materialized view as you would from a table or view.

For fast refresh use

create materialized view log on emp

Create materialized view empmview
tablespace tspa
parallel
build immediate
refresh fast on commit
as
select *
from emp
note :for fast refresh option Materialized view log is created on base table

A materialized view is mainly used for replication purpose.