访问函数中的调用关系

Question

我想用较少的查询调用关系到访问器函数

ticket有很多消息票证模型有访问器功能我想进入访问器功能如果ticket-> messages（） - > exists（）== TRUE返回messages body, or ** if ticket->messages()->exist() == TRUE** returns tickets body这行代码（$ ticket-> last_body）在视图中为每行写一个查询我想减少我的查询

门票型号：

class Ticket extends Model
{

    public function messages()
    {
        return $this->hasMany(TicketMessage::class, 'ticket_id');
    }

    public function getLastBodyAttribute()
    {

        if($this->messages()->exists()){
            return $this->messages()->orderByDesc('created_at')->first()->body;
        } else {
            return $this->body;
        }
    }
}

门票按摩属于门票

TicketMessage模型：

class TicketMessage extends Model
{
    public function ticket()
    {
        return $this->belongsTo(Ticket::class,'ticket_id');
    }
}

我得到自己的关系票，并传递给查看TicketController：

class TicketController extends Controller
{
    public function index(Request $request)
    {
        $tickets = Ticket::with('messages')
                        ->where('status', 'open')
                        ->get();

        return view('ticket::supporter.supporter', compact('tickets'));
    }
}

this line code $ticket->last_body make one Query for each row and i want to decrease my query 

**supporter.blade** :

    @foreach($tickets as $ticket)
        <a href="{{url(Route('show_client_ticket', ['id' => $ticket->id]))}}">   
            {{$ticket->subject}} 
        </a>

        <p style="color: #959A9D;">
            {{$ticket->last_body}} //this line returns too much  Query
        </p>
        <hr>
    @endforeach

Answer 1

试着改变这个。

 public function ticket()
    {
        return $this->belongsTo(Ticket::class,'ticket_id');
    }

对此。

 public function ticket()
    {
        return $this->belongsTo(Ticket::class,'id');
    }

因为模型的默认主键是“id”。

或者如果要更改主键。试试这个：

class Ticket extends Model
 {
  protected $primaryKey = 'ticket_id';

...