How to associate the database record with the object - symfony

Question

I follow the docs from here http://symfony.com/doc/current/book/doctrine.html
and I have a issue.
I created a relation between the category and the product model. The database has been updated correctly, model classes have right getters and setters, but if I try to run following code:
$product = $this->getDoctrine()->getRepository('AcmeStoreBundle:Product')
->findById(1);
$categoryName = $product->getCategory()->getName();
I gets an error:
FatalErrorException: Error: Call to a member function getName() on a
non-object in
D:\www\Symfony\src\Acme\StoreBundle\Controller\DefaultController.php
line 28
I checked it out and the category model class has getName() method and it is a public method.
My Product.orm.yml looks like
Acme\StoreBundle\Entity\Product:
type: entity
manyToOne:
category:
targetEntity: Category
inversedBy: products
joinColumn:
name: category_id
referencedColumnName: id
table: null
fields:
id:
type: integer
id: true
generator:
strategy: AUTO
name:
type: string
length: 255
price:
type: decimal
lifecycleCallbacks: { }
Category.orm.yml
Acme\StoreBundle\Entity\Category:
type: entity
oneToMany:
products:
targetEntity: Product
mappedBy: category
table: null
fields:
id:
type: integer
id: true
generator:
strategy: AUTO
name:
type: string
length: '255'
lifecycleCallbacks: { }
Product.php
...
/**
* #ORM\ManyToOne(targetEntity="Category", inversedBy="products")
* #ORM\JoinColumn(name="category_id", referencedColumnName="id")
*/
protected $category;
...
Category.php
...
/**
* #ORM\OneToMany(targetEntity="Product", mappedBy="category")
*/
protected $products;
public function __construct() {
$this->products = new ArrayCollection();
}
...
What's the problem?

Answer 1

You are retrieving a $category instead of a $product in your sample code.
$product = $this->getDoctrine()->getManager()->getRepository('AcmeStoreBundle:Product')->findOneById(1);
$categoryName = $product->getCategory()->getName();
note that you forgot the getManager()
Edit : You need to use findOneById() instead of findById. The first method will return only one single result (your object), the findBy* will return you an array of results on which you can't call getCategory() without traversing it inside a loop.