What is a Materialized View in Oracle and How is it Different from a Regular View?

A materialized view in Oracle is a database object that contains the results of a query. Unlike a regular view, which simply stores a query and re-executes it each time it is accessed, a materialized view pre-computes and stores the result set. This means that the data in a materialized view is physically stored on disk, similar to a table.

The main difference between a materialized view and a regular view is that a materialized view is a snapshot of the data at the time it was last refreshed, while a regular view always displays the most up-to-date data. Materialized views are often used in data warehousing and reporting scenarios where performance is critical, as they can significantly improve query performance by reducing the need to recompute results repeatedly.

In summary, materialized views provide a way to cache and persist the results of complex or frequently executed queries, whereas regular views are more of a dynamic query definition that always reflects the current state of the underlying data.