Specifying morphTo method target id column - laravel

Question

Is there a way to specify target id column on morphTo method?
I'll give an example which is in documentation for laravel:
Post - Id, text
Video - Id, url
Comment - Id, text, commentable_id, commentable_type
But what if Ids on post and video were renamed to custom_id? How would I set up my eloquent model then? Thanks.
Edit:
I still don't get it here is the complete code:
Table structure:
comments - id, text, commentable_id, commentable_type, user_id
posts - custom_id, text
videos - custom_id, url
users - id, name, email, password,...
Comment model:
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Comment extends Model
{
public function commentable()
{
return $this->morphTo();
}
}
Video model:
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Video extends Model
{
public function comments()
{
return $this->morphMany('App\Comment', 'commentable', 'commentable_type', 'commentable_id', 'custom_id');
}
}
Post model:
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Post extends Model
{
public function comments()
{
return $this->morphMany('App\Comment', 'commentable', 'commentable_type', 'commentable_id', 'custom_id');
}
}
User model:
<?php
namespace App;
use Illuminate\Notifications\Notifiable;
use Illuminate\Foundation\Auth\User as Authenticatable;
class User extends Authenticatable
{
use Notifiable;
/**
* The attributes that are mass assignable.
*
* #var array
*/
protected $fillable = [
'name', 'email', 'password',
];
/**
* The attributes that should be hidden for arrays.
*
* #var array
*/
protected $hidden = [
'password', 'remember_token',
];
public function comments()
{
return $this->hasMany('App\Comment');
}
}
TestController:
<?php
namespace App\Http\Controllers;
use App\User;
use Illuminate\Http\Request;
class TestController extends Controller
{
public function test()
{
$user = User::first();
$comments = $user -> comments;
foreach ($comments as $comment)
{
return $comment -> commentable;
}
}
}
And it still throws query exception Unknown column posts.id
Please explain. Thanks.

Answer 1

You can set the custom id field name in the relationship.
public function comments()
{
return $this->morphMany('App\Comment', 'commentable', 'commentable_type', 'commentable_id', 'custom_id');
}
There are the parameters
public function morphMany($related, $name, $type = null, $id = null, $localKey = null);
Edit : After going through the whole thing i've found out that using custom id only works from parent fetches the child relationship. But fails when trying to get the parent using the children. So fetching Post or Video from the comment would fail.
There's an active proposal on laravel internals to add the feature to allow specifying the custom id to make this work. https://github.com/laravel/internals/issues/587