10. You issue the following command: INSERT INTO homework10 (col1, col2, col3) VALUES (‘A’, NULL, ‘C’). The command will fail if which of the following statements is true? a. Col1 has a PRIMARY KEY co…
10. You issue the following command: INSERT INTO homework10 (col1, col2, col3) VALUES
(‘A’, NULL, ‘C’). The command will fail if which of the following statements is true?
a. Col1 has a PRIMARY KEY constraint enabled.
b. Col2 has a UNIQUE constraint enabled.
c. Col3 is defined as a DATE column.
d. None of the above would cause the command to fail.
11. Which of the following releases a lock currently held by a user on the HOMEWORK10 table?
a. A COMMIT command is issued.
b. A DDL command is issued to end a transaction.
c. The user exits the system.
d. A ROLLBACK command is issued.
e. all of the above
f. none of the above
12. Assume you have added eight new orders to the ORDERS table. Which of the following
is true?
a. Other users can view the new orders as soon as you execute the INSERT INTO
command.
b. Other users can view the new orders as soon as you issue a ROLLBACK command.
c. Other users can view the new orders as soon as you exit the system or execute a
COMMIT command.
d. Other users can view the new orders only if they place an exclusive lock on the table.
13. Which of the following commands removes all orders placed before April 1, 2009?
a. DELETE FROM orders WHERE orderdate < '01-APR-09';
b. DROP FROM orders WHERE orderdate < '01-APR-09';
c. REMOVE FROM orders WHERE orderdate < '01-APR-09';
d. DELETE FROM orders WHERE orderdate > ’01-APR-09′;
14. How many rows can be added to a table by executing the INSERT INTO … VALUES
command?
a. 1
b. 2
c. 3
d. unlimited
OR