5. Result- Solve the problem of inconsistency between attribute names and field names
1. Problem
database fields
Create a new project and test the inconsistency of the entity class fields before copying
There was a problem with the test
Solution:
alias
<select id="getUserById" parameterType="int" resultType="com.jiang.pojo.User">
select id,name,pwd as password from mybatis.user where id= #{id}
</select>2、resultMap
result set mapping
id name pwd
id name password<!--结果集映射-->
<resultMap id="UserMap" type="User">
<!--column数据库中的字段，property实体类中的属性-->
<result column="id" property="id"></result>
<result column="name" property="name"></result>
<result column="pwd" property="password"></result>
</resultMap>
<select id="getUserList" resultMap="UserMap">
select * from USER
</select>
The resultMap element is the most important and powerful element in MyBatis.
The design idea of ResultMap is to achieve zero configuration for simple statements, and for more complex statements, only need to describe the relationship between statements.
The great thing about ResultMaps - you don't have to explicitly configure them at all.
If only the world had always been this simple.
https://www.bilibili.com/video/BV1NE411Q7Nx?p=11&spm_id_from=pageDriver