主要是解决实体类中属性名和数据库中数据表的字段名不同问题,解决办法有2种:
1.查询数据时用别名,
- <select >
- select user_id id, user_name name from orders where user_id=#{id}
- </select>
<select >
select user_id id, user_name name from orders where user_id=#{id}
</select>
2.或者使用resultMap
- <select >
- select * from user_differ where user_id=#{id}
- </select>
-
- <resultMap >
- <id column="user_id" property="id"/>
- <result column="user_name" property="name"/>
- </resultMap>
- </mapper>
<select >
select * from user_differ where user_id=#{id}
</select>
<resultMap >
<id column="user_id" property="id"/>
<result column="user_name" property="name"/>
</resultMap>
</mapper>
Tip:这两种方法只能使用其中一种否则会报错