Symfony2 & Doctrine : One-To-One relation and persistence of the id references - symfony

Question

I have a problem with establishing a bidirectional One-To-One relationship between two entities.
I have an entity "Campaign" that CAN reference another entity "DonationData". A donation data that is created is always linked to a campaign. I want a bidirectional relationship because I want to be able to find the related campaign from a DonationData entity.
This is my code for the Campaign Entity :
<?php
/**
* #ORM\Entity
* ...
*/
class Campaign
{
...
/**
* #ORM\OneToOne(targetEntity="DonationData", mappedBy="campaign", cascade={"persist", "remove"})
*/
protected $donationData;
...
/**
* Set donationData
*
* #param DonationData $donationData
* #return Campaign
*/
public function setDonationData(DonationData $donationData = null)
{
$this->donationData = $donationData;
return $this;
}
...
?>
And the related code for my DonationData entity :
<?php
/**
* #ORM\Entity
* ...
*/
class DonationData
{
...
/**
* #ORM\OneToOne(targetEntity="Campaign")
* #ORM\JoinColumns({
* #ORM\JoinColumn(name="campaign_id", referencedColumnName="id")
* })
*/
protected $campaign;
...
/**
* Set campaign
* #param Campaign $campaign
*
* #return DonationData
*/
public function setCampaign($campaign)
{
$this->campaign = $campaign;
return $this;
}
...
?>
The piece of code where I'm adding my DonationData form in my Campaign Form (CampaignType.php)
<?php
...
->add('donationData', new DonationDataType(), array(
'label' => false
))
...
?>
And in the CampaignController.php side, when I'm handling the creation operations, I didn't change anything : I'm just persisting the related entity binded from the request, and then flushing the Entity Manager :
<?php
...
$em->persist($campaign);
$em->flush();
...
?>
My problem is when I want to persist a Campaign entity form that has an embedded DonationData form inside. I successfully persist both the Campaign and the DonationData entities, but there is only the donation_data_id reference in the Campaign entry that is persisted. When I look in database to the persisted DonationData, the campaign_id is always set to NULL.
Do you see any explanation for that?
Thank you.

Answer 1

In class DonationData, field $campaign you don't specify the inversedBy property, should be
#ORM\JoinColumn(name="campaign_id", referencedColumnName="id", inversedBy="donationData")
and did you set the cascade_validation default option in the parent form?
as in http://symfony.com/doc/current/reference/forms/types/form.html