What are materialized views?

Question

Can someone explain to me what views or materialized views are in plain everyday English please? I\'ve been reading about materialized views but I don\'t understand.

Answer 1

Yes. Materialized views are views with a base table underneath them. You define the view and Oracle creates the base table underneath it automatically.

By executing the view and placing the resulting data in the base table you gain performance.

They are useful for a variety of reasons. Some examples of why you would use a materialized view are:

1) A view that is complex may take a long time to execute when referenced

2) A view included in complex SQL may yield poor execution plans leading to performance issues

3) You might need to reference data across a slow DBLINK

A materialized view can be setup to refresh periodically.

You can specify a full or partial refresh.

Please see the Oracle documentation for complete information