When to use materialized view in Oracle DBMS?

Materialized View is used for replicate of data in the table

when we have a large number of record in our query. query reterive record after long time then we need to create materialized veiw to ger data speedly.

in data where house we create materialized view to get automatacelly data from client side

No need to use materialized views unless you are using Oracle version less than 12c, now you have the RESULT_CACHE hint which allows you to cache the result of queries, functions, views and tables. Cautious when using this feature as a tradeoff between memory usage and  hard disk usage  have to be  weighed, ideally it should be used if the underlying table(s) of a query don't change frequently.

When we need to pull huge data at the certain period

You can use materialized views to achieve one or more of the following goals:

• Ease Network Loads
• Create a Mass Deployment Environment
• Enable Data Subsetting
• Enable Disconnected Computing

materialised views are used when standard views (used to retrieve data from various tables without joins /foreign key relations) are not suggested or feasible to use.

unlike standard view we can periodically run these views as they are disk based views, but standard views generate data every time they are queried. this will result in better performance in terms of time every time we query the view.