Updating views in oracle

A View can also be used to improve security by restricting access to a predetermined set of rows or columns.

In addition to operating on base tables, one View can be based on another, a view can also JOIN a view with a table (GROUP BY or UNION).

In order to be updatable, a view cannot contain any of the following constructs: SET or DISTINCT operators, an aggregate or analytic function, a GROUP BY, ORDER BY, CONNECT BY, or START WITH clause, a subquery (or collection expression) in a SELECT list or finally (with some exceptions) a JOIN .

Using views encourages the use of Shared SQL with the benefit of reduced memory usage.

The data dictionary views ALL_UPDATABLE_COLUMNS, DBA_UPDATABLE_COLUMNS, and USER_UPDATABLE_COLUMNS indicate which view columns are updatable.

An updatable materialized view lets you insert, update, and delete.

You can define a materialized view on a base table, partitioned table or view and you can define indexes on a materialized view.