<update id="updateProduct" parameterType="com.my.o2o.entity.Product"
            keyProperty="product_id" useGeneratedKeys="true">
        UPDATE tb_product
        <set>
            <if test="productName != null">product_name=#{productName},</if>
            <if test="productDesc != null">product_desc=#{productDesc},</if>
            <if test="imgAddr != null">img_addr=#{imgAddr},</if>
            <if test="normalPrice != null">normal_price=#{normalPrice},</if>
            <if test="promotionPrice != null">promotion_price=#{promotionPrice},</if>
            <if test="priority != null">priority=#{priority},</if>
            <if test="lastEditTime != null">last_edit_time=#{lastEditTime},</if>
            <if test="enableStatus != null">enable_status=#{enableStatus},</if>
            <if test="productCategory != null
				 and productCategory.productCategoryId != null">
                product_category_id=#{productCategory.productCategoryId}
            </if>
        </set>
        WHERE product_id = #{productId}
        AND shop_id=#{shop.shopId}
    </update>

对于WHERE的条件，shop_id = #{shop.shopId} ,老师在课里说是为了避免操作到其他店铺下的商品，可是在前端，当前店铺的商品不就只能显示出属于当前shopId下面的商品么？ 怎么会修改到其他店铺底下的商品呢？我还是觉得这里的shop_id = #{shop.shopId} 有点多余