ALTER VIEW

Syntax

Purpose

To explicitly recompile a view that is invalid. Explicit recompilation allows you to locate recompilation errors before run time. You may want to recompile a view explicitly after altering one of its base tables to ensure that the alteration does not affect the view or other objects that depend on it.

When you issue an ALTER VIEW statement, Oracle recompiles the view regardless of whether it is valid or invalid. Oracle also invalidates any local objects that depend on the view.

Notes: This statement does not change the definition of an existing view. To redefine a view, you must use CREATE VIEW with OR REPLACE. See "CREATE VIEW". If you alter a view that is referenced by one or more materialized views, those materialized views are invalidated. Invalid materialized views cannot be used by query rewrite and cannot be refreshed. To revalidate an invalid materialized view, see "ALTER MATERIALIZED VIEW / SNAPSHOT". For information on materialized views in general, see Oracle8i Data Warehousing Guide. See Also: Oracle8i Concepts for more about dependencies among schema objects.

Prerequisites

The view must be in your own schema or you must have ALTER ANY TABLE system privilege.

Keywords and Parameters

schema	is the schema containing the view. If you omit schema, Oracle assumes the view is in your own schema.
view	is the name of the view to be recompiled.
COMPILE	causes Oracle to recompile the view. The COMPILE keyword is required.

Example

To recompile the view CUSTOMER_VIEW, issue the following statement:

ALTER VIEW customer_view
    COMPILE; 

If Oracle encounters no compilation errors while recompiling CUSTOMER_VIEW, CUSTOMER_VIEW becomes valid. If recompiling results in compilation errors, Oracle returns an error and CUSTOMER_VIEW remains invalid.

Oracle also invalidates all dependent objects. These objects include any procedures, functions, package bodies, and views that reference CUSTOMER_VIEW. If you subsequently reference one of these objects without first explicitly recompiling it, Oracle recompiles it implicitly at run time.