Question

我正在制作 Laravel 5.4 应用程序，但我很难弄清楚如何使用雄辩的关系来构建数据。

这是我的模型以及我希望它们如何相关：

学校→有课程，用户和活动
用户→可以属于某所学校。可以有课程和会话（有案例）
班级→属于学校。有用户和科目。可以做作业
主题→属于班级
会话→属于用户。可以有案例
案例→属于某个会话
活动→属于学校
家庭作业→属于班级

我应该如何在Laravel 5.4项目中使用雄辩的关系函数（belongsTo，hasMany等）来构建它？

Answer 1

假设Class，User和Event模型具有属性school_id，并且您使用的主键是相应模型的id，则Class，User，Event和School模型应如下所示。

学校

class School extends Model
{
public function users(){
    return $this->hasMany('App\User');
}

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

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

用户

class User extends Model
{
public function school(){
    return $this->belongsTo('App\School');
}

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

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

类

class Class extends Model
{
public function school(){
    return $this->belongsTo('App\School');
}

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

public function subjects(){
    return $this->hasMany('App\Subject');
}
public function homeworks(){
    return $this->hasMany('App\Homework');
}
}

事件

class Class extends Model
{
public function school(){
    return $this->belongsTo('App\School');
}

}

您可以使用这些关系来定义具有链接功能的查询。例如如果你想获得与学校相关的所有活动，其中id属性等于$ id，你可以写，

$events = App\School::find($id)->events;

Laravel Documentation解释得很好

Answer 2

正确的方法是

<强>学校

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

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

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

<强>类

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

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

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


public function users()
{
    return $this->belongsToMany('App\User','class_users','class_id','user_id');
    // this should be many to many because users can also have many classes
}

用户

public function school() { return $this->belongsTo('App\School'); } public function classes() { return $this->belongsToMany('App\Class','class_users','user_id','class_id'); // this should be many to many as explained to class } public function sessions() { return $this->belongsToMany('App\Session','session_users','user_id','session_id'); // like classes do, this should be many to many relationship because sessions can also have many users }

<强> SUBJECT

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

<强> SESSION

public function users() { return $this->belongsToMany('App\User','session_users','session_id','user_id'); // should be many to many as well } public function cases() { return $this->hasMany('App\Case'); }

<强> CASE

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

<强> EVENT

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

<强> HOMEWORK

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

Answer 3

创建School模型和基础表后，就可以创建关系了。打开School模型并创建一个名为classes，users和events的公共方法;在它内部引用hasMany方法：

学校：

class School extends Model {

  public function classes()
  {
    return $this->hasMany('App\Class');
  }
  public function users()
  {
    return $this->hasMany('App\User');
  }
  public function events()
  {
    return $this->hasMany('App\Event');
  }

}

用户：

class User extends Model {

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

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

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

}

班级：

class Class extends Model {

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

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

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

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

}

主题：

class Subject extends Model {

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

}

会话：

class Session extends Model {

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

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

}

案例：

class Case extends Model {

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

}

活动：

class Event extends Model {

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

}

作业：

class Homework extends Model {

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

}

有关hasMany关系的更多详细信息，请查看此处的链接：EasyLaravelBook

雄辩的关系（Laravel 5.4）

3 个答案: