diff --git a/2207/MySQL数据库操作综合练习题答案.md b/2207/MySQL数据库操作综合练习题答案.md index 1ef4220..a531ae4 100644 --- a/2207/MySQL数据库操作综合练习题答案.md +++ b/2207/MySQL数据库操作综合练习题答案.md @@ -33,5 +33,17 @@ ALTER TABLE customers_info DROP c_city; **2** ```sql +#(1)创建表时 添加外键约束并指定外键约束名称 +CREATE TABLE orders( + o_num INT(11) PRIMARY KEY AUTO_INCREMENT, + o_date DATE, + c_id INT(11), + CONSTRAINT fk_cid FOREIGN KEY(c_id) REFERENCES customers_info(c_num) +); +#(2) +#删除指定外键 +ALTER TABLE orders DROP FOREIGN KEY orders_ibfk_1; +#删除指定表 +DROP TABLE orders; ```