A. NOT NULL
B. PRIMARY KEY
C. FOREIGN KEY
D. CHECK
E. UNIQUE

A. ALTER VIEW emp_dept_vu (ADD manager_id NUMBER);
B. MODIFY VIEW emp_dept_vu (ADD manager_id NUMBER);
C. ALTER VIEW emp_dept_vu AS   SELECT employee_id, employee_name,   department_name, manager_id   FROM employee e, departments d   WHERE e.department_id = d.department_id;
D. MODIFY VIEW emp_dept_vu AS   SELECT employee_id, employee_name,   department_name, manager_id   FROM employees e, departments d   WHERE e.department_id = d.department_id;
E. CREATE OR REPLACE VIEW emp_dept_vu AS   SELECT employee_id, employee_name,   department_name, manager_id   FROM employees e, departments d   WHERE e.department_id = d.department_id;
F. You must remove the existing view first, and then run the CREATE VIEW command   with a new column list to modify a view.