MyBatis-Oracle生成主键，嵌套对象中的List增加

<insert id="insert">
<selectKey order="BEFORE" keyProperty="id" resultType="int">
SELECT SEQ_ROLE_PERMISSION.NEXTVAL FROM dual
</selectKey>
INSERT INTO t_role(id,name) VALUES(#{id},#{name})
</insert>

<insert id="insertClazzStudent">
    insert into t_clazz_student(id,clazz,student)
    select SEQ_CLAZZ_STUDENT.NEXTVAL id,A.*
    from(
    <foreach collection="studentList" item="student" separator="union all" >
        select
        #{id} class,
        #{student.id} student
        from dual
    </foreach>
    )A
</insert>