View Constraints

Declarative primary key, unique key and foreign key constraints can now be defined against views. The NOT NULL constraint is inherited from the base table so it cannot be declared explicitly. The constraints are not validated so they must be defined with the DISABLE NOVALIDATE clause:

CREATE VIEW Emp_view

 (Id PRIMARY KEY DISABLE NOVALIDATE, firstname)

AS SELECT employee_id, first_name

FROM employees

WHERE department_id = 10;

ALTER VIEW Emp_view

ADD CONSTRAINT emp_view_unq

UNIQUE (first_name) DISABLE NOVALIDATE;