mybatis中使用resultMap时需注意

如果是实体中是直接引用别的对象的具体参数字段，直接用原始方式就行

    <resultMap id="baseMap" type="com.ei.medical.modules.model.EduEducationKnowledge">
        <result column="visitNumber" property="visitNumber"/>
        <result column="patientName" property="patientName"/>
        <result column="sendTime" property="sendTime"/>
        <result column="wardCode" property="wardCode"/>
        <result column="wardName" property="wardName"/>
        <result column="categoryCode" property="categoryCode"/>
        <result column="title" property="title"/>
        <result column="content" property="content"/>
        <result column="cover" property="cover"/>
    </resultMap>
    
    <select id="getAllBy" resultMap="baseMap">
        SELECT
            eer.visit_number as visitNumber,
            eer.patient_name as patientName,
            eer.send_time as sendTime,
            eek.id as id,
            eek.ward_code as wardCode,
            eek.ward_name as wardName,
            eek.category_code as categoryCode,
            eek.title as title,
            eek.content as content,
            eek.cover as cover
        FROM
            edu_education_record AS eer,
            edu_education_knowledge AS eek
        WHERE
            eer.education_knowledge_id=eek.id
    </select>

如果实体中是引用的别的实体对象，应该使用collection 标签

<resultMap id="baseMap" type="com.ei.medical.modules.model.EduEducationKnowledge">
        <result column="wardCode" property="wardCode"/>
        <result column="wardName" property="wardName"/>
        <result column="categoryCode" property="categoryCode"/>
        <result column="title" property="title"/>
        <result column="content" property="content"/>
        <result column="cover" property="cover"/>
        <collection property="eduEducationRecord" ofType="com.ei.medical.modules.model.EduEducationRecord">
            <result column="visitNumber" property="visitNumber"/>
            <result column="patientName" property="patientName"/>
            <result column="sendTime" property="sendTime"/>
        </collection>
    </resultMap>

    <select id="getAllBy" resultMap="baseMap">
        SELECT
            eer.visit_number as visitNumber,
            eer.patient_name as patientName,
            eer.send_time as sendTime,
            eek.id as id,
            eek.ward_code as wardCode,
            eek.ward_name as wardName,
            eek.category_code as categoryCode,
            eek.title as title,
            eek.content as content,
            eek.cover as cover
        FROM
            edu_education_record AS eer,
            edu_education_knowledge AS eek
        WHERE
            eer.education_knowledge_id=eek.id
    </select>

如果实体中引用的是别的对象的集合，可以使用association 标签来写

    <resultMap id="baseMap" type="com.ei.medical.modules.model.EduEducationKnowledge">
        <result column="wardCode" property="wardCode"/>
        <result column="wardName" property="wardName"/>
        <result column="categoryCode" property="categoryCode"/>
        <result column="title" property="title"/>
        <result column="content" property="content"/>
        <result column="cover" property="cover"/>
        <association property="eduEducationRecordList" resultMap="base2Map"/>
    </resultMap>

    <resultMap id="base2Map" type="com.ei.medical.modules.model.EduEducationRecord">
        <result column="visitNumber" property="visitNumber"/>
        <result column="patientName" property="patientName"/>
        <result column="sendTime" property="sendTime"/>
    </resultMap>
    
    
    <select id="getAllBy" resultMap="baseMap">
        SELECT
            eer.visit_number as visitNumber,
            eer.patient_name as patientName,
            eer.send_time as sendTime,
            eek.id as id,
            eek.ward_code as wardCode,
            eek.ward_name as wardName,
            eek.category_code as categoryCode,
            eek.title as title,
            eek.content as content,
            eek.cover as cover
        FROM
            edu_education_record AS eer,
            edu_education_knowledge AS eek
        WHERE
            eer.education_knowledge_id=eek.id
    </select>

tips：
使用resultMap的时候，应该直接用as后面的字段名，即自己命的名字
如果没有使用as的话，直接使用数据库中原本的名字

resultMap中各个标签的含义
在这里插入图片描述

a little rookie

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mybatis中使用resultMap时需注意

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