Oracle 11G SQL 2nd Edition By Joan Casteel – Test bank

Chapter 4: Constraints

TRUE/FALSE

1. Constraints are rules used to enforce business rules, practices, and policies. ANS: T PTS: 1 REF: 100
2. Constraints are used to ensure the accuracy and integrity of the data contained in the database. ANS: T PTS: 1 REF: 100
3. A constraint can only be created as part of the CREATE TABLE command. ANS: F PTS: 1 REF: 102
4. A constraint name can consist of up to 10 characters. ANS: F PTS: 1 REF: 101
5. A primary key is usually given the abbreviation _pk in the constraint name if the name is assigned by the user.

   ANS: T PTS: 1 REF: 101

6. Any constraint can be created at the table or the column level.

   ANS: F PTS: 1 REF: 102

7. A foreign key constraint can only be created at the column level.

   ANS: F PTS: 1 REF: 102

8. A NOT NULL constraint can only be created at the column level.

   ANS: T PTS: 1 REF: 102

9. A constraint for a composite primary key must be created at the table level.

   ANS: T PTS: 1 REF: 103

10. The CONSTRAINT keyword is required if the user is going to assign a name to a constraint.

ANS: T PTS: 1 REF: 102 11. A constraint is always enforced at the table level.

ANS: T PTS: 1 REF: 102
12. The table level approach can be used to create any constraint, except a CHECK constraint.

ANS: F PTS: 1 REF: 102

1

13. A PRIMARY KEY constraint will make certain the column designated as the primary key does not contain a NULL value.

    ANS: T PTS: 1 REF: 103

14. The MODIFY clause is used with the ALTER TABLE command to add a PRIMARY KEY constraint to an existing table.

    ANS: F PTS: 1 REF: 103

15. Only one PRIMARY KEY constraint can exist for each table.

    ANS: T PTS: 1 REF: 103

16. A FOREIGN KEY constraint can be added to the column of a table to ensure that the referenced data value actually exists in the other table.

    ANS: T PTS: 1 REF: 106

17. If a FOREIGN KEY constraint exists, then a record cannot be deleted from the parent table if that row is referenced by an entry in the child table.

    ANS: T PTS: 1 REF: 108

18. A FOREIGN KEY constraint will not allow a row containing a NULL value in the foreign key column to be added to the table.

    ANS: F PTS: 1 REF: 106

19. A UNIQUE constraint is the same as a PRIMARY KEY constraint, except that it will accept NULL values.

    ANS: T PTS: 1 REF: 111

20. A CHECK constraint requires that a data value meet a certain condition before the record is added to the database table.

    ANS: T PTS: 1 REF: 112