একাধিক কলামে কম্পোজিট PRIMARY KEY সরাতে ALTER TABLE সাথে DROP PRIMARY KEY ব্যবহার করা হয়।
উদাহরণ
room_allotment টেবিলে id এবং Name কলামে কম্পোজিট PRIMARY KEY:
mysql> DESCRIBE room_allotment; +--------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+-------------+------+-----+---------+-------+ | id | int(11) | NO | PRI | 0 | | | Name | varchar(20) | NO | PRI | | | | RoomNo | int(11) | YES | | NULL | | +--------+-------------+------+-----+---------+-------+
PRIMARY KEY ড্রপ:
mysql> ALTER TABLE room_allotment DROP PRIMARY KEY; Query OK, 0 rows affected (0.19 sec) mysql> DESCRIBE room_allotment; +--------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+-------------+------+-----+---------+-------+ | id | int(11) | NO | | 0 | | | Name | varchar(20) | NO | | | | | RoomNo | int(11) | YES | | NULL | | +--------+-------------+------+-----+---------+-------+
এখন Key কলামে PRI নেই, কম্পোজিট PRIMARY KEY সরিয়ে ফেলা হয়েছে।
