How to solve the problem of inconsistency between Mybatis attribute name and field name

table of Contents

Problem Description

Method one: alias in the SQL statement

Method 2: resultMap

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Problem Description

 

What if the fields in the database and the attributes in the entity class are inconsistent?

 

 

 

Method one: alias in the SQL statement

 

The alias name looks perfect, but if there are many aliased fields, the SQL statement will be very bloated

select id,name,pwd from mybatis.user where id = #{id}

 

 

Method 2: resultMap

 

In the specific Mapper.xml file, add the resultMap tag. This is actually very flexible. For example, I only have pwd! = Password, so there is no need to map other fields.

This approach transfers non-essential operations in SQL to the <resultMap> tag. However, if you check 5 tables across 5 entities, <resultMap> will be very bloated, and the optimization plan will be shared in a blog

<!--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="pwd" property="password"/>
</resultMap>

<select id="getUserById" resultMap="UserMap">
    select * from user where id = #{id}
</select>