hasMany  ------------------------- (一对多关系)比如 一个人有多个订单 

hasOne --------------------------(一对一关系)比如一个订单只能能一个人购买

下面是代码

创建连个表 

CREATE TABLE `customer` (

  `id` int(10) NOT NULL AUTO_INCREMENT,   `customer_name` varchar(255) DEFAULT NULL,   PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;

CREATE TABLE `order` (

  `id` int(10) NOT NULL AUTO_INCREMENT,   `order_name` varchar(255) DEFAULT NULL,   `customer_id` int(10) DEFAULT NULL,   PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;

配置两个模型

Order.php

class  Order  extends  \yii\db\ActiveRecord{

       public function getCustomer(){         return $this->hasOne(Customer::className(), ['id' => 'customer_id']);      }

}

Customer.php

namespace app\models;

use app\models\Order; use Yii; class  Customer extends  \yii\db\ActiveRecord{    public  function  getOrders(){       return $this->hasMany(Order::className(), ['customer_id' => 'id']);     } }

控制器的代码

HasController.php

 public  function  actionIndex(){

        //一对多查询         $id = 1;         $customer = Customer::findOne($id);         $list = $customer->getOrders()->asArray()->all();         //一对一查询         $order = Order::findOne(['id'=>1]);         $customer =  $order->getCustomer()->asArray()->one();         print_r($customer);      }