mysql>
mysql> CREATE TABLE myTable
-> (
-> OrderID SMALLINT UNSIGNED NOT NULL PRIMARY KEY,
-> ModelID SMALLINT UNSIGNED NOT NULL
-> );
Query OK, 0 rows affected (0.03 sec)
mysql>
mysql> desc myTable;
+---------+----------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------+----------------------+------+-----+---------+-------+
| OrderID | smallint(5) unsigned | NO | PRI | | |
| ModelID | smallint(5) unsigned | NO | | | |
+---------+----------------------+------+-----+---------+-------+
2 rows in set (0.00 sec)
mysql>
mysql> ALTER TABLE myTable
-> ADD UNIQUE (OrderID, ModelID);
Query OK, 0 rows affected (0.06 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql>
mysql> drop table myTable;
Query OK, 0 rows affected (0.00 sec)
mysql>