EmbeddedId那一节 想插入记录 但是总是执行删除操作

Hibernate: insert into imooc_db.t_students (address, phone, postCode, birthday, gender, major, sname, id, sid) values (?, ?, ?, ?, ?, ?, ?, ?, ?)

    drop table if exists imooc_db.t_students

    create table imooc_db.t_students (
        id varchar(255) not null,
        sid varchar(255) not null,
        address varchar(255),
        phone varchar(255),
        postCode varchar(255),
        birthday datetime,
        gender varchar(255),
        major varchar(255),
        sname varchar(255),
        primary key (id, sid)
    )