Mybatis collection 使用的注意点

mybatis  的一对多

<?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.fw.dao.OrderDAO">
	<resultMap type="com.ly.fw.entity.Order" id="order">
		<id column="id" property="id" />  
        <result column="orderId" property="orderId" /> 
        <result column="user" property="user" />  
        <result column="address" property="address" />    
        <result column="tel" property="tel" />
        <result column="code" property="code" />   
        <result column="orderPrice" property="orderPrice" /> 
        <result column="transNum" property="transNum" /> 
   		<result column="status" property="status" /> 
   		<result column="time" property="time" /> 
   		<collection property="productList"  column="orderId"  resultMap="opro"/>  
	</resultMap>
	<resultMap type="com.ly.fw.entity.OrderProduct" id="opro">
		<id column="opid" property="opId" />  
        <result column="orderId" property="orderId" /> 
        <result column="productId" property="productId" />  
        <result column="count" property="count" />    
        <result column="price" property="price" />
       	<result column="size" property="size" />
	</resultMap>

  <select id="getAll" resultMap="order">
        select o.*,p.* from `order` as o, order_product as p where o.orderId=p.orderId order by o.`time` desc limit #{start},#{end}

    </select>
</mapper>

　　实体类中：

 

    private long id ;
    private String orderId ;//订单id
    private String user ;//用户
    private String address ;//地址
    private String tel ;//电话
    private String code ;//邮编
    private String orderPrice ;//订单金额
    private String transNum;
    private int status;//状态。
    private Date time;//订单时间
    
    private List<OrderProduct> productList;// 一对多

　　正常情况这样是直接能返会集合中的数据的。但是今天遇到个问题是返还的集合中始终只有一条数据。数据库中返回应该不只一条.

查了半天资料发现：两张表的主键名称不能一样，我就是由于两张表的主键 都是 “id”  所以返回只有一条数据