mysql> select * from books;
+----+--------------------------------------+---------------+-----------+
| id | title                                | author        | available |
+----+--------------------------------------+---------------+-----------+
|  1 | The Hitchhiker's Guide to the Galaxy | Douglas Adams |         1 |
+----+--------------------------------------+---------------+-----------+
1 row in set (0.00 sec)

mysql> START TRANSACTION;
Query OK, 0 rows affected (0.00 sec)

mysql> UPDATE books SET available = 0;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> SELECT available FROM books;
+-----------+
| available |
+-----------+
|         0 |
+-----------+
1 row in set (0.00 sec)

mysql> ROLLBACK;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> SELECT available FROM books;
+-----------+
| available |
+-----------+
|         0 |
+-----------+
1 row in set (0.00 sec)

mysql>