Symfony join entities in one-to-many relationship - symfony

Question

I am working on a Symfony project recording sales as relating to stock.
My reasoning:
one sale item is associated to one stock item
one stock item can be associated to multiple sale items
As a result, I setup a one-to-many sale-to-stock relationship as show in the following code snippets:
class Sale
{
/**
* #var integer
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #var float
*
* #ORM\Column(name="cost", type="float")
*/
private $cost;
/**
* #var \DateTime
*
* #ORM\Column(name="date", type="datetime")
*/
private $date;
/**
* #ORM\ManyToOne(targetEntity="iCerge\Salesdeck\StockBundle\Entity\Stock", inversedBy="sales")
* #ORM\JoinColumn(name="sid", referencedColumnName="id")
*/
protected $stock;
...
... and ...
class Stock
{
/**
* #var integer
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #var string
*
* #ORM\Column(name="name", type="string", length=255)
*/
private $name;
/**
* #var \DateTime
*
* #ORM\Column(name="created", type="datetime")
*/
private $created;
/**
* #var \DateTime
*
* #ORM\Column(name="updated", type="datetime")
*/
private $updated;
/**
* #ORM\OneToMany(targetEntity="iCerge\Salesdeck\SalesBundle\Entity\Sale", mappedBy="stock")
*/
protected $sales;
...
NOW, if my code for implementing a one-to-many relationship is correct, I am trying to load a sale object with it's associated stock data in one query using the following code:
public function fetchSale($sid){
$query = $this->createQueryBuilder('s')
->leftjoin('s.stock', 't')
->where('s.id = :sid')
->setParameter('sid', $sid)
->getQuery();
return $query->getSingleResult();
}
The fetchSale function is from my projects SaleRepository.php class.
The leftjoin part of the query is what I hoped would successfully fetch the related stock information but I just get no output ([stock:protected]) as is shown below:
myprog\SalesProj\SalesBundle\Entity\Sale Object
(
[id:myprog\SalesProj\SalesBundle\Entity\Sale:private] => 50
[cost:myprog\SalesProj\SalesBundle\Entity\Sale:private] => 4.99
[date:myprog\SalesProj\SalesBundle\Entity\Sale:private] => DateTime Object
(
[date] => 2015-04-18 17:12:00
[timezone_type] => 3
[timezone] => UTC
)
[stock:protected] =>
[count:myprog\SalesProj\SalesBundle\Entity\Sale:private] => 5
)
How I can successfully fetch a sales' related stock data in the same query?

Answer 1

Doctrine is lazy-loading by default, so it's possible that $stock hasn't been initialized and the dump is not showing it. Try dumping $sale->getStock(). That tells Doctrine to go fetch it.
You can also force the loading of the Stock by selecting it:
public function fetchSale($sid){
$query = $this->createQueryBuilder('s')
->leftjoin('s.stock', 't')
->where('s.id = :sid')
->setParameter('sid', $sid)
->select('s', 't')
->getQuery();
return $query->getSingleResult();
}
By the way, fetchSale($sid) as it is now is the same as calling:
$entityManager->getRepository('SalesBundle:Sale')->find($sid);

Answer 2

You can use Doctrine's eager loading feature.
1. Always load associated object:
If you always want to fetch the stock object when loading the sale object, you can update your entity definition (see docs for #ManyToOne) by adding a fetch="EAGER" to the #ManyToOne definition:
/**
* #ORM\ManyToOne(targetEntity="iCerge\Salesdeck\StockBundle\Entity\Stock", inversedBy="sales", fetch="EAGER")
* #ORM\JoinColumn(name="sid", referencedColumnName="id")
*/
protected $stock;
Doctrine will then take care of loading all required objects in as few queries as possible.
2. Sometimes load associated object:
If you want to load the associated object only in some queries and not by default, according to the manual you can also tell Doctrine to use eager loading on a specific query. In your case, this may look like:
public function fetchSale($sid){
$query = $this->createQueryBuilder('s')
->where('s.id = :sid')
->setParameter('sid', $sid)
->getQuery();
$query->setFetchMode("FQCN\Sale", "stock", \Doctrine\ORM\Mapping\ClassMetadata::FETCH_EAGER);
return $query->getSingleResult();
}