Multiple persist in Symfony 3 Doctrine - symfony

Question

I have a database with 3 tables, Equipment, transaction and transactionReceive. In the future there will be multiple transactionXYZ, one for each type of transaction. I used a joined inheritance to link transactionReceive with transaction. I also use a Many to one association between Equipment and transaction, since a piece of equipment can have multiple transactions.
I am currently working on adding a piece of equipment. This is a two step process. It should:
1: Create the piece of equipment
2: Create the transaction/transactionReceive
My issue is that when I try to set the equipmentId to persist the transaction, it throws an exception saying it is null.
My code is as follow:
$em->persist($equipmentData);
$em->flush();
$trans = new TransactionReceive();
$trans->setEquipmentId($equipmentData->getId());
//Here I set all transactions info
$em->persist($trans);
$em->flush();
Thanks
EDIT:
Apparently my issue would be related to the insert with the ManyToOne association. I noticed it because I get the same error even if I hardcode a value for the equipmentId in the transaction.
EDIT 2:
Transaction entity
namespace AppBundle\Entity;
use Doctrine\ORM\Mapping as ORM;
/**
* Transaction
*
* #ORM\Table(name="transaction")
* #ORM\Entity(repositoryClass="AppBundle\Repository\TransactionRepository")
*
* #ORM\InheritanceType("JOINED")
* #ORM\DiscriminatorColumn(name="transactionType", type="string")
* ORM\#DiscriminatorMap({
* "receive" = "TransactionReceive",
* "changeout" = "TransactionChangeoutWheelset",
* })
*/
class Transaction
{
/**
* #var int
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #var int
* #ORM\ManyToOne(targetEntity="Equipment")
* #ORM\Column(name="equipmentId", type="integer")
*/
private $equipmentId;
/**
* #return int
*/
public function getequipmentId()
{
return $this->equipmentId;
}
/**
* #param int $equipmentId
*
* #return self
*/
public function setEquipmentId($equipmentId)
{
$this->equipmentId= $equipmentId;
return $this;
}
// Other attributes, getters and setters
TransactionReceive entity
namespace AppBundle\Entity;
use Doctrine\ORM\Mapping as ORM;
use AppBundle\Entity\Transaction;
/**
* TransactionReceive
*
* #ORM\Table(name="transaction_receive")
* #ORM\Entity(repositoryClass="AppBundle\Repository\TransactionReceiveRepository")
*/
class TransactionReceive extends Transaction
{
/**
* #var int
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #var int
*
* #ORM\Column(name="gsThickness", type="integer")
*/
private $gsThickness;
/**
* Get id
*
* #return int
*/
public function getId()
{
return $this->id;
}
/**
* Set gsThickness
*
* #param integer $gsThickness
*
* #return TransactionReceive
*/
public function setGsThickness($gsThickness)
{
$this->gsThickness = $gsThickness;
return $this;
}
/**
* Get gsThickness
*
* #return int
*/
public function getGsThickness()
{
return $this->gsThickness;
}
}

Answer 1

Since your equipementId proprety is a foreign key, you need to set it to an object equipement, not only it's Id.
Replacing the line $trans->setEquipmentId($equipmentData->getId()); by
$trans->setEquipmentId($equipmentData);
should do the trick for you.