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Use two columns as the combined primary key

mysql> mysql> CREATE TABLE myTable     -> (     ->    OrderID     SMALLINT UNSIGNED NOT NULL,     ->    ModelID     SMALLINT UNSIGNED NOT NULL,     ->    Description VARCHAR(40),     ->    PRIMARY KEY (OrderID, ModelID)     -> ); 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   | PRI |         |       | | Description | varchar(40)          | YES  |     | NULL    |       | +-------------+----------------------+------+-----+---------+-------+ 3 rows in set (0.02 sec) mysql> mysql> drop table myTable; Query OK, 0 rows affected (0.00 sec) mysql>