如何在Yii2中处理多对多关系 [英] How do I work with many-to-many relations in Yii2

问题描述

例如由于文档( http://www.yiiframework.com/doc-2.0/guide-db-active-record.html#relational-data )，您可以通过(one-many = company-zone)这样的方式链接两个模型:

For example in one-to-many due to documentation (http://www.yiiframework.com/doc-2.0/guide-db-active-record.html#relational-data) you can link two models in this way (one-many = company-zone):

$defaultZone = new Zone;
$defaultZone->name = Zone::DEFAULT_ZONE;
$company->link('zones', $defaultZone);

但是当您拥有像tbl_user_market(user_id, market_id)这样的运输表时，它如何用于多对多关系?

But how it works for many-to-many relations when you have transit table like tbl_user_market(user_id, market_id)?

推荐答案

在使用联结表进行多对多关系时，您必须

When using a junction table for many-to-many relations, you have to

1. 定义关系
2. 将两个模型链接在一起

在用户模型中定义以下关系函数:

In the User model define the following relation function:

public function getMarkets() {
    return $this->hasMany(Market::className(), ['id' => 'market_id'])
      ->viaTable('tbl_user_market', ['user_id' => 'id']);
}

在市场"模型中定义以下关系函数:

In the Market model define the following relation function:

public function getUsers() {
    return $this->hasMany(User::className(), ['id' => 'user_id'])
      ->viaTable('tbl_user_market', ['market_id' => 'id']);
}

最后，在保存两个模型之后，将它们链接在一起:

And finally, after saving both models, link them together:

$user = new User;
$user->name = 'Foo';
$user->save();

$market = new Market;
$market->name = 'Bar';
$market->save();

$user->link('markets', $market);

对link()的调用将填充联结表.

The call to link() will populate the junction table.

参考: http://www. yiiframework.com/doc-2.0/yii-db-baseactiverecord.html#link()-详细信息

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