You can hide a materialized view's definition from users. When you hide a materialized view, you obfuscate the view definition stored in the database, making the view invisible in the catalog. The view can still be directly referenced, and is still eligible for use during query processing. When a materialized view is hidden, debugging using the debugger will not show the view definition, nor will the definition be available through procedure profiling, and the view can be still unloaded and reloaded into other databases.
Hiding a materialized view is irreversible, and can only be performed using a SQL statement.
Connect to the database as a user with DBA authority, or as owner of the materialized view.
Execute an ALTER MATERIALIZED VIEW statement with the SET HIDDEN clause.
The following statements create a materialized view, EmployeeConfid3, refreshes it, and then obfuscate its view definition.
CREATE MATERIALIZED VIEW EmployeeConfid3 AS SELECT EmployeeID, Employees.DepartmentID, SocialSecurityNumber, Salary, ManagerID, Departments.DepartmentName, Departments.DepartmentHeadID FROM Employees, Departments WHERE Employees.DepartmentID=Departments.DepartmentID; REFRESH MATERIALIZED VIEW EmployeeConfid3; ALTER MATERIALIZED VIEW EmployeeConfid3 SET HIDDEN;
When you are done with this example, you should drop the materialized view you created. Otherwise, you will not be able to make schema changes to its underlying tables Employees and Departments, when trying out other examples. You cannot alter the schema of a table that has enabled, dependent materialized view. See Drop materialized views.
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