Select only certain columns in related model when eager loading - laravel

Question

I have two related models:
class Attribute extends Eloquent
{
public function categories()
{
return $this->hasMany('Category');
}
}
class Category extends Eloquent
{
public function attributes()
{
return $this->belongsTo('Attribute');
}
}
I want to return all attributes and their categories as a JSON object, but I only want to select certain fields in both models (i.e. not return fields like 'created_at' in the JSON).
I've tried this:
$attributes = Attribute::select('id', 'name')
->with(['categories' => function ($query) {
$query->select('categories.id', 'categories.name', 'categories.attribute_id');
}]);
Response::JSON($attributes->get());
but despite the select query for the related model, unrequested fields are returned:
attributes: [{
id: 3,
name: "Organisation",
categories: [{
id: 3,
name: "Asia HQ",
attribute_id: 3,
created_at: "2013-11-30 00:00:00",
updated_at: "2013-11-30 00:00:00"
}]
}]
How do I select only certain columns in related model when eager loading?

Answer 1

What about an eloquent method that will look like this?
public function dynamicAttributes($array_columns) {
return $this->belongs_to('User')->select((array) $array_comuns);
}
Where $array_columns could be a string or array of strings representing a columns you want?

Answer 2

Make use of select() laravel method:
$attributes = Attribute::select('id', 'name')->with(['categories' =>function($query){
$query->select(['categories.id', 'categories.name','categories.attribute_id'])->get();
}]);
Response::JSON($attributes->get());
To make select method work in eager loading you need to include foreign_key in
selected column list.
Reference : http://laravel-tricks.com/tricks/column-selection-in-eager-loading

Answer 3

If you want to always return those specific fields from the categories relation, defining the select in the relationship will work, but if you would like to do it on the fly for one specific query, ask Eloquent to only return those fields.
$attributes = Attribute::with(['categories' => function ($query) {
$query->select('id', 'name', 'attribute_id');
}])->get('id', 'name');
... Or you could use Fluent
DB::table('attributes')
->join('categories', 'attributes.id', '=', 'categories.attribute_id')
->select('attributes.id', 'attributes.name', 'categories.id', 'categories.name', 'categories.attribute_id')
->get();

Answer 4

Try this:
$attributes = Attribute::select('id', 'name')
->with([
'categories:categories.id,categories.name,categories.attribute_id',
]);
Response::JSON($attributes->get());
Please notice: no space after comma in argument list