Laravel嵌套关系

Question

我在使用非常嵌套的关系在laravel中正常工作时遇到了很多麻烦.

想要的行为如下,

我按ID选择一个事件,我想看看哪些人订阅了它. 现在问题是事件和人之间有一些表格.

这是有效的查询!

SELECT persons.id, 
       persons.firstname, 
       persons.lastname, 
       event_scores.score 
FROM   events 
       JOIN cities 
         ON cities.id = events.city_id 
       JOIN companies 
         ON cities.id = companies.city_id 
       JOIN persons 
         ON companies.id = persons.company_id 
       JOIN event_scores 
         ON event_scores.person_id = persons.id 
WHERE  event_scores.event_id = 1 
GROUP  BY persons.id 

这些是我的关系

事件模型

class Event extends Eloquent
{
    protected $table = 'events';

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

城市模型

class City extends Eloquent
{
    protected $table = 'cities';

    public function companies()
    {
        return $this->hasMany('Company');
    }

    public function event()
    {
        return $this->hasMany('Event');
    }
}

公司模式

class Company extends Eloquent {

    protected $table = 'companies';

    public function persons()
    {
        return $this->hasMany('Person');
    }

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

人模型

class Person extends Eloquent
{
    protected $table = 'persons';

    public function company()
    {
        return $this->belongsTo('Company');
    }

    public function eventscore()
    {
        return $this->belongsToMany('Event', 'event_scores', 'person_id', 'event_id')
            ->withPivot('score')
            ->withTimestamps();
    }
}

我试过了什么

return Event::with('city')->with('company')->get();

和

return Event::with('city')
    ->whereHas('companies', function($query) use ($company_id){
        $query->where('company_id', $company_id);
    })->get();

还有很多其他的可能性,我真的坚持这个.在laravel中实现这种嵌套关系链接是否如此困难？

谢谢!

Answer 1

return Event::with('city.companies.persons')->get();

如果您只想从persons表中选择某些字段,请使用:

return Event::with(['city.companies.persons' => function ($query) {
    $query->select('id', '...');
}])->get();

Answer 2

对于城市和公司特定领域,您需要分发具有说服力的人.例如:

return Event::with([
    'city' => function ($query) {
        $query->select('id', '...');
    },
    'city.companies' => function ($query) {
        $query->select('id', '...');
    },
    'city.companies.persons' => function ($query) {
        $query->select('id', '...');
    }
])->get();

Answer 3

return Event::with(['city:id,name', 'city.companies:id,name', 'city.companies.persons:id,name'])->get();

请注意，在嵌套级别（至少是中级）中，您还必须指定 FK 到父关系，否则您将获得该嵌套关系的空集合！我花了几个小时才弄清楚这一点。

Answer 4

对于事件模型中的两级\xd8\x8c

\n

public function cities()\n{\n    return $this->belongsToMany(City::class)->with('companies');\n}\n

\n