Mybatis自增主键返回与非自增主键返回

自增主键返回

<insert id="zizenginsertToStudent" parameterType="com.nsu.mybatis.practice.Student">


  <selectKey keyProperty="sid" order="AFTER" resultType="java.lang.Integer">
  SELECT LAST_INSERT_ID()
  selectKey>
     INSERT INTO student(sname,sex) VALUES(#{sname},#{sex})
 insert>

      String resource = "mybatis-config.xml";
      SqlSession sqlSession = null;

      Student student=new Student();

      InputStream is = Resources.getResourceAsStream(resource);

         SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
          sqlSession = factory.openSession();

      Student student2=new Student();
      student2.setSex("na");
      student2.setSname("yy");

        sqlSession.insert("test.zizenginsertToStudent", student2);

        sqlSession.commit();

        System.out.println(student2.getSid());
        sqlSession.close();

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非自增主键返回

使用mysql的uuid（）函数生成主键，需要修改表中di字段类型为String，长度设置成35位。
执行顺序：

1. 先通过UUID（）查询到主键，将主键输入到sql语句中
2. 执行uuid（）顺序相对于insert语句之前执行