You need to modify the STUDENTS table to add a primary key on the STUDENT_ID column. The
table is currently empty.
Which statement accomplishes this task?
A.
ALTER TABLE students ADD PRIMARY KEY student_id;
B.
ALTER TABLE students ADD CONSTRAINT PRIMARY KEY (student_id);
C.
ALTER TABLE students ADD CONSTRAINT stud_id_pk PRIMARY KEY student_id;
D.
ALTER TABLE students ADD CONSTRAINT stud_id_pk PRIMARY KEY (student_id);
E.
ALTER TABLE students MODIFY CONSTRAINT stud_id_pk PRIMARY KEY (student_id);
Explanation:
ALTER TABLE table_name
ADD [CONSTRAINT constraint] type (coloumn);
Incorrect answer:
Awrong syntax
Bwrong syntax
Cwrong syntax
Eno such MODIFY keyword
Refer: Introduction to Oracle9i: SQL, Oracle University Study Guide, 10-17