Materialized View vs View
May I know the difference for these two items?
Data in materialized view can be refresh but so as view when we use select statement. Why not just use view instead of materialized view?
Answer
When you need performance on data that don't need to be up to date to the very second, materialized views are better, but your data will be older than in a standard view.
While creating Materialized view Oracle creates two objects, a table where the results are actually materialized and a materialized view that has all the metadata (the query, the attributes, etc.).
But while creating View Oracle creates only one object, which has all the metadata(the query, the attributes, etc.)