MySQL.索引
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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