Laravel query scope confusion (hasmany relation, error: object could not be converted to string)

Question

I want to change my gettitle method into a scope but receive the error "object could not be converted to string".

Do query scopes have a speed advantage over methods? What is the advantage of creating a scope?

I have a table with products. Then there is a table with product_titles which also have a language_id.

Each product can have several titles since they can be in different languages.

public function scopeGettitle($language_id="1")
{

    return self::product_titles()->select('title','information')
                                ->where("language_id","=",$language_id);
}

  public function product_titles ()
{
    return $this->hasMany(ProductTitle::class);
}

In the blade file I use this code:

$title=$book->gettitle()->first();

Thank you

Edit: This seems the right way:

public function scopeGettitle($query, $language_id="1")
{
return $query
    ->select('title','information')
    ->where("language_id","=",$language_id);
}

$producttitle=$product->product_titles()->gettitle()->first();

My question is if there is any reason why this is better than to simply create a method which I can call in this way: $producttitle=$product->gettitle();

And to create a "bylanguage" scope in the Title model.

Answer 1

Scope parameters should be defined after the $query parameter

$query

\\Illuminate\\Database\\Eloquent\\Builder

public function scopeGettitle($query, $language_id="1")
{
    return $query
        ->product_titles()
        ->select('title','information')
        ->where("language_id","=",$language_id);
}