如何在 Eloquent 上设置条件关系

Question

我有这个（简化的）table结构：

users
- id
- type (institutions or agents)

institutions_profile
- id
- user_id
- name

agents_profile
- id
- user_id
- name

而且我需要在 Users 模型上创建一个 profile 关系，但以下方法不起作用：

class User extends Model
{
    public function profile()
    {
        if ($this->$type === 'agents')
            return $this->hasOne('AgentProfile');
        else
            return $this->hasOne('InstitutionProfile');
    }    
}

我怎样才能实现这样的目标？

Answer 1

看起来应该是 $this->type 而不是 $this->$type - 因为 type 是属性，而不是变量。

Answer 2

您可以使用另一种方法来完成此操作，请检查：

a blog Post and Video model could share a polymorphic relation to a Tag model. Using a many-to-many polymorphic relation allows you to have a single list of unique tags that are shared across blog posts and videos. First, let's examine the table structure:

https://laravel.com/docs/5.4/eloquent-relationships#many-to-many-polymorphic-relations

Answer 3

让我们采用不同的方法来解决您的问题。首先让我们分别设置各个模型的关系。

class User extends Model
{
    public function agentProfile()
    {
        return $this->hasOne(AgentProfile::class);
    }    

    public function institutionProfile()
    {
        return $this->hasOne(InstitutionProfile::class);
    }

    public function schoolProfile()
    {
        return $this->hasOne(SchoolProfile::class);
    }

    public function academyProfile()
    {
        return $this->hasOne(AcademyProfile::class);
    }

    // create scope to select the profile that you want
    // you can even pass the type as a second argument to the 
    // scope if you want
    public function scopeProfile($query)
    {
        return $query
              ->when($this->type === 'agents',function($q){
                  return $q->with('agentProfile');
             })
             ->when($this->type === 'school',function($q){
                  return $q->with('schoolProfile');
             })
             ->when($this->type === 'academy',function($q){
                  return $q->with('academyProfile');
             },function($q){
                 return $q->with('institutionProfile');
             });
    }
}

现在您可以像这样访问您的个人资料

User::profile()->first();

这应该会给您正确的配置文件。希望对你有帮助。

如何在 Eloquent 上设置条件关系

How to setup conditional relationship on Eloquent

relationships

laravel

eloquent