Home » Oracle » 1z0-051 » Which two statements are true about constraints?
Which two statements are true about constraints? (Choose two.)
A. The UNIQUE constraint does not permit a null value for the column.
B. A UNIQUE index gets created for columns with PRIMARY KEY and UNIQUE constraints.
C. The PRIMARY KEY and FOREIGN KEY constraints create a UNIQUE index.
D. The NOT NULL constraint ensures that null values are not permitted for the column.
Correct Answer: BD
Explanation/Reference:
Explanation:
B: A unique constraint can contain null values because null values cannot be compared to anything.
D: The NOT NULL constraint ensure that null value are not permitted for the column
Incorrect answer:
Astatement is not true
Cstatement is not true
Refer: Introduction to Oracle9i: SQL, Oracle University Study Guide, 10-9
|
Download Printable PDF. VALID exam to help you PASS.
|
 |
