Mybatis一对多映射实战解析-优快云博客

本文详细介绍了Mybatis中的一对多映射配置和使用，包括配置文件设置、实体类设计、Mapper接口及XML文件的编写，通过实例展示了如何实现从父表获取多个子表数据的操作，帮助读者深入理解Mybatis一对多映射的原理。

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.ly.boilingwater.modules.gen.dao.SysTableDao">

    <sql id="selectSql">
        SELECT a.table_name as table_name,
        a.table_comment as table_comment,
        b.COLUMN_NAME as COLUMN_NAME,
        b.column_comment as column_comment,
        b.column_type as column_type,
        b.column_key as column_key
        FROM information_schema.TABLES a
        LEFT JOIN information_schema.COLUMNS b ON a.table_name = b.TABLE_NAME
        WHERE a.table_schema = 'boiling_water'
        <if test="tableName != null and tableName.trim() != ''">
            and a.table_name = #{tableName}
        </if>
        ORDER BY a.table_name;
    </sql>

    <select id="queryALl" resultMap="tableResult">
        <include refid="selectSql"></include>
    </select>

    <resultMap id="tableResult" type="com.ly.boilingwater.modules.gen.entity.SysTableEntity">
        <result property="tableName" column="table_name"/>
        <result property="tableComment" column="table_comment"/>
        <collection property="sysColumnEntityList" ofType="com.ly.boilingwater.modules.gen.entity.SysColumnEntity">
            <result property="columnName" column="COLUMN_NAME"/>
            <result property="columnComment" column="column_comment"/>
            <result property="columnType" column="column_type"/>
            <result property="columnKey" column="column_key"/>
        </collection>
    </resultMap>
</mapper>