Laravel Eloquent无法得到简单的hasMany关系工作

Background

I have an internationalized DB that stores its strings for different languages like this:

products
    id
    price

product_translation
    id
    product_id
    language_id
    name
    description

languages
    id
    name (e.g. 'English', 'German')
    code (e.g. 'en', 'de')

With appropriate Models for each table (Product, ProductTranslation, Language). In my views I want to fetch a list of products like this:

// get first 20 products, list name and price.
@foreach(Product::take(20)->get() as $product)
{{$product->translations->name}} {{$product->price}}
@endforeach

Problem

My app will return product names according to what the current App::getLocale() is set to (i.e. en and de).

I'm just starting out with Laravel's Eloquent, I'm unsure how to specify the correct relationships (or if I'm actually doing it correctly at all).

My attempt

I have specified a OneToMany relationship in between Product and ProductTranslation:

class Product extends \Eloquent {

    protected $with = ['translations'];

    public function translations()
    {
        return $this->hasMany('ProductTranslation');
    }
}

This works fine but will return all the translations (we only want the current locale).

I then specify a OneToOne relationship between ProductTranslation and Language:

class ProductTranslation extends \Eloquent {

    protected $with = ['language'];

    public function language()
    {
        return $this->hasOne('Language')
        ->where('code', App::getLocale());
    }
}

I know this doesn't work and I am stumped at what to do next. Does anyone have a cleaner approach?

class ProductTranslation extends \Eloquent {

    protected $with = ['language'];

    public function language()
    {
        return $this->hasOne('Language');
    }
}

In route or controller

ProductTranslation::language()->where('code', '=', App::getLocale())->get();

To keep this in the model do this

public static function getLocale() 
{
    return static::language()->where('code', '=', App::getLocale())->get();;
}

Call the function using ProductTranslation::getLocale()

Laravel has built-in system for translations and with a little work you can make it work with the database, however that is probably not what it was designed for.

You can't fetch the ones you want cause relationships are based on ids (foreign keys) and not for string constraints or similar.

In your view you could look into filtering out the ones that are not for the language code you wanted using filter(): http://laravel.com/docs/4.2/eloquent#collections

Or You could consider moving the translations to the proper place as hard-coded: http://laravel.com/docs/4.2/localization and if that is not possible you could look into fetching the translations from database still using the method described by that link. Eventually it just returns the array of the translations and does not care how did you build the array, hard-coded or from database.