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Detailed explanation of the use of YII2 multi-table association
Detailed explanation of the use of YII2 multi-table association
Recently, I encountered problems related to YII2 multi-table association in the project, and did not find suitable information, so I sorted it out myself so that I can refer to it when I need it in the future or friends who need it can refer to it. This article mainly introduces you to the use of multi-table associations in YII2. Friends who need it can take a look below. I hope to be helpful.
Preface
This article gives a brief introduction to the multi-table related query of YII2.0. The article introduces it in detail through example code. I won’t say much below. Let’s take a look at the detailed introduction:
First, let’s explain the table structure
Table structure
Now there are order table, user table, product list table, product inventory table
##In YII, if you want to directly associate other tables for query, you need to define their association in the model first
Order
class Order extends \yii\db\ActiveRecord.{
// 关联函数以get+要关联的数据表名来命名
// 这是获取下订单的客户
public function getUser(){
// 第一个参数为要关联的子表模型类名，
// 第二个参数指定 通过子表的user_id，关联主表的usesr_id字段
// 这里写清楚点大概意思就是User.user_id => Order.user_id
return $this->hasMany(User::className(), ['user_id' => 'user_id']);
}
}1, hasMany, hasOne use
Associated use
//获取订单信息 $order = Order::findOne(1); //根据订单信息获取到用户信息 $user = $order->user;
//返回订单信息（包括用户信息） $order = Order::find(1)->with('user'); //或者 $order = Order::find(1)->getUser();
SELECT * FROM order WHERE id=1; SELECT * FROM user WHERE user.user_id=order.user_id;
As you can see from the above, there are two ways to access an association
●If called as a function, an ActiveQuery object will be returned ( $customer->getOrders()->all()) ●If called as an attribute, the result of the model will be returned directly ($customer->orders)Association result cache
If the order table changes at this time, we hope to query again$user = $order->user;
//先释放缓存 unset($order->user); $order->user;
Cross-table query
User
public function getOrder() {
return $this->hasMany(Order::className(), ['user_id' => 'user_id']);
}
public function getOrderGoods() {
return $this->hasMany(OrderGoods::className(), ['order_id' => 'order_id'])->
via('order');
}Note here: The second order_id in getOrderGoods refers to the Order associated with getOrder order_id, the first order_id refers to the order_id in OrderGoods.
but! We also have the simplest method, which is to use SQL statements!$map = 'select user.name, order.id, order_goods.goods_id, goods.goods_name, stock.stock_count from user LEFT JOIN order ON order.user_id = user.user_id LEFT JOIN order_goods ON order_goods.order_id = order.order_id LEFT JOIN goods ON goods.goods_id = order_goods.goods_id LEFT JOIN stock ON stock.goods_id = goods.goods_id'; $list1 = Article::findBySql($map)->asArray()->all();
Related recommendations:
Detailed explanation of the simple extension of Yii framework batch insertion data Class
Detailed explanation of restful api authorization verification of yii2
Yii solves DeleteAll connection table deletion Error reporting
The above is the detailed content of Detailed explanation of the use of YII2 multi-table association. For more information, please follow other related articles on the PHP Chinese website!
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