1 环境
(1) 数据库
CREATE TABLE `t_student` (
`n_id` int(11) NOT NULL AUTO_INCREMENT,
`c_name` varchar(255) DEFAULT NULL,
`c_age` int(12) DEFAULT NULL,
PRIMARY KEY (`n_id`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
CREATE TABLE `t_teacher` (
`n_id` int(11) NOT NULL AU