What are the restrictions in updatable materialized view?

An updatable materialized view based on a master table or master materialized view that has defined column default values does not automatically use the master’s default values. A DELETE CASCADE constraint used with an updatable materialized view must be deferrable.

How do I grant a materialized view privilege?

The privileges required to create a materialized view should be granted directly rather than through a role. To create a materialized view in your own schema: You must have been granted the CREATE MATERIALIZED VIEW system privilege and either the CREATE TABLE or CREATE ANY TABLE system privilege.

What are the restrictions for fast refresh materialized views with subqueries?

General Restrictions on Fast Refresh The materialized view must not contain references to non-repeating expressions like SYSDATE and ROWNUM. The materialized view must not contain references to RAW or LONG RAW data types. It cannot contain a SELECT list subquery.

What does a fast refresh means in materialized view?

Fast refresh for a materialized view containing joins and aggregates is possible after any type of DML to the base tables (direct load or conventional INSERT , UPDATE , or DELETE ). It can be defined to be refreshed ON COMMIT or ON DEMAND .

Which of the following conditions must exist for a materialized view to be used in a query rewrite?

A materialized view must be enabled for query rewrite. The rewrite integrity level should allow the use of the materialized view. For example, if a materialized view is not fresh and query rewrite integrity is set to ENFORCED , then the materialized view is not used.

What is fast complete force refresh in materialized view?

“Complete Refresh” means you truncate entire materialized view and insert new data. “Fast Refresh” means you update (or insert/delete) only the rows which have been changed on master tables.

How long did Oracle materialized view refresh run?

The “Complete” refresh (7.75 mins) is more faster than the “Fast” refresh (48.9 mins), The parameter “atomic_refresh=FALSE” works only with “complete” refresh, so “truncate” is only possible with “complete“.

Which of the following conditions must exist for a materialized view to be used in a query rewrite Mcq?

What is enable query rewrite in Oracle materialized view?

This feature, called query rewrite, enables the optimizer to use a materialized view in place of the table queried by the materialized view, even if the materialized view is not named in the query. For example, if you have a large SALES table, you may create a materialized view that sums the SALES data by region.

What is enable fast refresh materialized view in Oracle?

For fast refresh to be possible, the SELECT list must contain all of the GROUP BY columns (if present), and there must be a COUNT(*) and a COUNT(column) on any aggregated columns. Also, materialized view logs must be present on all tables referenced in the query that defines the materialized view.

What causes a materialized view to become invalid?

When an MV is created, the materialized view depends on the master tables referenced in its definition. Any DML operation, such as an INSERT, or DELETE, UPDATE, or DDL operation on any dependency in the materialized view will cause it to become invalid.