5张表之间的laravel关系答案

【问题标题】：laravel relationship between 5 tables5张表之间的laravel关系
【发布时间】：2018-12-22 16:58:31
【问题描述】：

我有 5 个表 User, Profile, Address,State,City 。需要在表之间创建关系。Address 在表中有 State id ， City id 和 Profile id 。Profile 在表中有 User Id 。City 有 State Id在表中。表之间的关系怎么写

class City extends Model
{
    public function state() {
        return $this->belongsTo('App\State');
    }

    public function addresses() {
        return $this->hasMany('App\Address');
    }
}


class State extends Model
{
    public function cities() {
        return $this->hasMany('App\City');
    }

    public function addresses() {
        return $this->hasMany('App\Address');
    }
}

class Profile extends Model
{
    public function address() {
        return $this->belongsTo('App\Address');
    }
    public function user() {
        return $this->belongsTo('App\User');
    }
}

class Address extends Model
{
    public function profile() {
        return $this->belongsTo('App\Profile');
    }
    public function city() {
        return $this->belongsTo('App\City');
    }
    public function state() {
        return $this->belongsTo('App\State');
    }

}

// users table
public function profile(){
    return $this->hasOne('App\Profile');
}

【问题讨论】：

请说明您面临的问题...

标签： laravel relationship

【解决方案1】：

一般来说你的模型设计是正确的，我已经编辑了一些部分。试试下面的代码。

class City extends Model
{
     public function state()  
     {
         return $this->belongsTo('App\State');
     }

     public function addresses() 
     {
         return $this->hasMany('App\Address');
     }
}


class State extends Model
{
     public function cities() 
     {
          return $this->hasMany('App\City');
     }

     public function addresses() 
     {
          return $this->hasMany('App\Address');
     }
}

class Profile extends Model
{
     public function addresses() 
     {
         return $this->hasMany('App\Address');
     }

     public function user() 
     {
         return $this->belongsTo('App\User');
     }
}

class Address extends Model
{
      public function profile() 
      {
           return $this->belongsTo('App\Profile');
      }

      public function city() 
      {
           return $this->belongsTo('App\City');
      }

      public function state() 
      {
           return $this->belongsTo('App\State');
      }
}

class User extends Model
{
     public function profile()
     {
          return $this->hasOne('App\Profile');
     }
}

顺便说一下，Laravel 关系会根据你的方法名称添加默认键。如果您对此有疑问，可以从官方文档中找到信息。例如：

$this->belongsTo('App\Model', 'foreign_key', 'other_key');

【讨论】：

【解决方案2】：

正如@mustafa.akcoban 所说...

当你使用 belongsTo 时，Eloquent 的工作方式如下

$this->belongsTo('App\City', 'foreign_key', 'other_key');
// foreign_key = is the primary key in the related model, by default 'id' for Eloquent 
// other_key = is the field in the current model that contains the id of the other model, by default othermodelname_id for Eloquent
// For eg. 'App\City', 'id', 'city_id'

当你使用 hasMany Eloquent 时，工作如下

$this->hasMany('App\Model', 'currentmodel_id', 'primary_key');
// currentmodel_id = is the field that contains the current model primary key in the related model
// primary_key = is the current primary key model that will be in the other model, by default id for Eloquent
// For eg. 'App\City', 'state_id', 'id'

请记住，您可以或不能使用第二个和第三个参数，如果出现问题，Laravel 转储会告诉您在表中没有找到哪一列，您可以修复。

请试着练习一下，然后告诉我它是如何工作的 :)

【讨论】：