Doctrine One to Many relationship - php

Question

I got confuse in doctrine one to many relationship.
Question 1:
Correct me if I am wrong. I assume that when I try to
$em = $this->getDoctrine()->getManager();
$product_repo = $em->getRepository('MyBundle:Product');
$products = $product_repo->findAll();
dump($products);
I will see the related features attached to the $features variable, so when I use $products->getFeatures() I will have Feature object in array form. But from the dump debug I didn't not see anything attached to it instead I got this:
On the other end I also do this
$em = $this->getDoctrine()->getManager();
$feature_repo = $em->getRepository('MyBundle:Features');
$features = $product_repo->findAll();
dump($features);
This time I can see the Product object is attached to the $product variable.
My question is, is there any problem why I can't get data from the variable $features? Or doctrine wouldn't load the related data by default.
Question 2:
If we were assumed that the data is able to load into the feature $variable, is it possible that I can filter the data (eg. where feature.name = 'fly') instead of load all of the related feature.
==========================================================================
My Demo Entity
<?php
use Doctrine\Common\Collections\ArrayCollection;
/** #Entity **/
class Product
{
// ...
/**
* #OneToMany(targetEntity="Feature", mappedBy="product")
**/
private $features;
// ...
public function __construct() {
$this->features = new ArrayCollection();
}
}
/** #Entity **/
class Feature
{
// ...
/**
* #ManyToOne(targetEntity="Product", inversedBy="features")
* #JoinColumn(name="product_id", referencedColumnName="id")
**/
private $product;
// ...
}
Product table (in database): id, description, name
Feature table (in database): id, description, name, table_id

Answer 1

Assuming that your dump function is symfony/var-dumper and not a custom function
Question 1
Yes, nested collection are not displayed by default by dump function, its about performance. This is not a Doctrine related issue. Your data are loaded here.
You can play around with advanced use of var-dumper, like casters ( http://symfony.com/doc/current/components/var_dumper/advanced )
Question 2
You have differents ways to solve your question :
In Controller : Create your custom method in Product
Criteria better solution
Product::getFeaturesByName($name='fly'){
$criteria = Criteria::create();
$criteria->where(Criteria::expr()->eq('name', $name));
return $this->features->matching($criteria);
}
Filter
Product::getFeaturesByName($name='fly'){
return $this -> features ->filter(
function($entry) use ($name) {
return $entry->getName() == $name;
}
);
}
);
}
In Twig Template : filter in loop
{% for product in products %} {# start browse products #}
{% for feature in product.features if feature.name='ok' %}{# start browse features #}
{% endfor %}{# end browse features #}
{% endfor %}{# end browse products #}
Hope this will help you
regards