mybatis映射和条件查询

mybatis

mybatis绑定接口

<mapper namespace="com.ruoyi.web.practice.mapper.CmsLinkMapper">

mybatis映射(数据库的字段与实体类的映射)

<resultMap type="CmsLink" id="CmsLinkResult">
        <result property="linkId"    column="link_id"    />
        <result property="siteId"    column="site_id"    />
        <result property="linkName"    column="link_name"    />
        <result property="linkUrl"    column="link_url"    />
        <result property="linkImage"    column="link_image"    />
        <result property="clicks"    column="clicks"    />
        <result property="createTime"    column="create_time"    />
        <result property="updateTime"    column="update_time"    />
        <result property="sort"    column="sort"    />
        <result property="isShow"    column="is_show"    />
        <result property="status"    column="status"    />
        <result property="remark"    column="remark"    />
 </resultMap>

把公共的的sql语句提取出来

<sql id="selectCmsLinkVo">
select link_id, site_id, link_name, link_url, link_image, clicks, create_time, update_time, sort, is_show, status, remark from cms_link
</sql>

把公共的的sql语句通过Id引过来

<select id="selectCmsLinkList" parameterType="CmsLink" resultMap="CmsLinkResult">
  <include refid="selectCmsLinkVo"/>
      <where>
         <if test="siteId != null "> and site_id = #{siteId}</if>
         <if test="linkName != null  and linkName != ''"> and link_name like concat('%', #{linkName}, '%')</if>
         <if test="linkUrl != null  and linkUrl != ''"> and link_url = #{linkUrl}</if>
         <if test="linkImage != null  and linkImage != ''"> and link_image = #{linkImage}</if>
         <if test="clicks != null "> and clicks = #{clicks}</if>
         <if test="sort != null  and sort != ''"> and sort = #{sort}</if>
         <if test="isShow != null  and isShow != ''"> and is_show = #{isShow}</if>
         <if test="status != null  and status != ''"> and status = #{status}</if>
        </where>
</select>

插入语句设置条件

 <insert id="insertCmsLink" parameterType="CmsLink" useGeneratedKeys="true" keyProperty="linkId">
        insert into cms_link
        <trim prefix="(" suffix=")" suffixOverrides=",">
            <if test="siteId != null">site_id,</if>
            <if test="linkName != null and linkName != ''">link_name,</if>
            <if test="linkUrl != null">link_url,</if>
            <if test="linkImage != null">link_image,</if>
            <if test="clicks != null">clicks,</if>
            <if test="createTime != null">create_time,</if>
            <if test="updateTime != null">update_time,</if>
            <if test="sort != null">sort,</if>
            <if test="isShow != null">is_show,</if>
            <if test="status != null">status,</if>
            <if test="remark != null">remark,</if>
        </trim>
        <trim prefix="values (" suffix=")" suffixOverrides=",">
            <if test="siteId != null">#{siteId},</if>
            <if test="linkName != null and linkName != ''">#{linkName},</if>
            <if test="linkUrl != null">#{linkUrl},</if>
            <if test="linkImage != null">#{linkImage},</if>
            <if test="clicks != null">#{clicks},</if>
            <if test="createTime != null">#{createTime},</if>
            <if test="updateTime != null">#{updateTime},</if>
            <if test="sort != null">#{sort},</if>
            <if test="isShow != null">#{isShow},</if>
            <if test="status != null">#{status},</if>
            <if test="remark != null">#{remark},</if>
        </trim>
    </insert>

修改语句设置条件

<update id="updateCmsLink" parameterType="CmsLink">
        update cms_link
        <trim prefix="SET" suffixOverrides=",">
            <if test="siteId != null">site_id = #{siteId},</if>
            <if test="linkName != null and linkName != ''">link_name = #{linkName},</if>
            <if test="linkUrl != null">link_url = #{linkUrl},</if>
            <if test="linkImage != null">link_image = #{linkImage},</if>
            <if test="clicks != null">clicks = #{clicks},</if>
            <if test="createTime != null">create_time = #{createTime},</if>
            <if test="updateTime != null">update_time = #{updateTime},</if>
            <if test="sort != null">sort = #{sort},</if>
            <if test="isShow != null">is_show = #{isShow},</if>
            <if test="status != null">status = #{status},</if>
            <if test="remark != null">remark = #{remark},</if>
        </trim>
        where link_id = #{linkId}
    </update>

删除语句

<delete id="deleteCmsLinkByIds" parameterType="String">
        delete from cms_link where link_id in
        <foreach item="linkId" collection="array" open="(" separator="," close=")">
            #{linkId}
        </foreach>
</delete>
<!--foreach元素的属性主要有item，index，collection，open，separator，close-->

<!--collection该属性指定你要遍历的集合名称，然后在调用该方法的时候，通过参数的方式传递过来-->

<!--item用来临时存放迭代集合中当前元素的值，便于在foreach中使用-->

<!--index这个属性用来指定用来访问迭代集合下标的名称。如：index="myIndex"，则#{myIndex}用来访问当前迭代的下标。下标从0开始。-->

<!--open将该属性指定的值添加到foreach迭代后拼出字符串的开始。如：拼凑in子语句的开始部分“(”-->

<!--close: 将该属性指定的值添加到foreach迭代拼出字符串的结尾。如：拼凑in子语句的介绍部分"）"。-->

<!--separator用来分割foreach元素迭代的每个元素-->