A very small integer.
The signed range is -128 to 127.
The unsigned range is 0 to 255.
mysql>
mysql> CREATE TABLE myTable(
-> ID TINYINT UNSIGNED NOT NULL DEFAULT 1,
-> Name VARCHAR(50) NOT NULL
-> );
Query OK, 0 rows affected (0.03 sec)
mysql>
mysql> INSERT INTO myTable (Name)VALUES ('A');
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> select * from myTable;
+----+------+
| ID | Name |
+----+------+
| 1 | A |
+----+------+
1 row in set (0.00 sec)
mysql>
mysql> drop table myTable;
Query OK, 0 rows affected (0.00 sec)
mysql>