MySQL.索引

-- 单字段索引
CREATE INDEX LAST_NAME_INDEX 
    -> ON EMPLOYEE_TBL (LAST_NAME);
Query OK, 0 rows affected (0.06 sec)


-- 唯一索引
CREATE UNIQUE INDEX LAST_NAME_UNIQUE_INDEX
    -> ON EMPLOYEE_TBL (LAST_NAME);
ERROR 1062 (23000): Duplicate entry ‘GLASS‘ for key ‘LAST_NAME_UNIQUE_INDEX‘


-- 组合索引
CREATE INDEX ORDER_INDEX
    -> ON ORDERS_TBL (CUST_ID, PROD_ID);
Query OK, 0 rows affected (0.02 sec)


-- 修改索引
ALTER INDEX INDEX_NAME


-- 删除索引
DROP INDEX LAST_NAME_INDEX
    -> ON EMPLOYEE_TBL;
Query OK, 0 rows affected (0.03 sec)
Records: 0  Duplicates: 0  Warnings: 0

DROP INDEX ORDER_INDEX
    -> ON ORDERS_TBL;
Query OK, 0 rows affected (0.04 sec)
Records: 0  Duplicates: 0  Warnings: 0