Laravel Eloquent HasManyThrough returning empty array - php

Question

I am having trouble getting a query from HasManyThrough relation in Eloquent.
These are my tables
PAGES
id
columns
slideshow_fk
SLIDESHOWS
id
columns
SLIDES
id
columns
slideshow_id
My Page model:
class Page extends Model
{
public function slideshow_id(){
return $this->belongsTo(Slideshow::class);
}
public function slides(){
return $this->hasManyThrough('App\Slide','App\Slideshow','id','slideshow_id','slideshow_fk');
}
}
Controller
$page=Page::where("slug","=",$slug)->with('slides')->first();
Query log: I am not Page ID:3 with slideshow_fk:1, [? = 1]
select `slides`.*, `slideshows`.`id` from `slides` inner join `slideshows` on `slideshows`.`id` = `slides`.`slideshow_id` where `slideshows`.`id` in (?)
page->slides array:
[]
PhpMyAdmin SQL copy/paste:
http://prntscr.com/e0hy4e
Which are the correct 3 slides I need for my page.
Why do I get an empty array?

Answer 1

You cannot you hasManyThrough() here as your implementation doesn't support the need for one.
Say you have three models A, B and C and A want to connect to C via B.
Then if you want to use hasManyThrough()
B needs to have A's primary key as a foreign key
C needs to have B's primary key as a foreign key
That is A <- B <- C
If I put this to your example, what you have is
A have B's primary key as a foreign key
C have B's primary key as a foreign key
Which is A -> B <- C.
What you can do here is define models like this.
class Pages extends Model
{
public function slideshow()
{
return $this->belongsTo(Slideshow::class);
}
}
class Slideshow extends Model
{
public function slides()
{
return $this->hasMany(Slides::class);
}
}
class Slides extends Model
{
}
And query like
$pags = Pages::with('slideshow.slides')->where('slug', $slug)->first();
I suggest using proper naming conventions.