How to remove usage of cascade={"remove","persist"} from entities in Symfony2? - symfony

Question

I am working on a project where there I am forced to use cascade={"remove","persist"} because of the problem described here.
Reading through the documentation, to quote:
Even though automatic cascading is convenient it should be used with care. Do not blindly apply cascade=all to all associations as it will unnecessarily degrade the performance of your application. For each cascade operation that gets activated Doctrine also applies that operation to the association, be it single or collection valued.
And I see that the same can be fixed if I use
$em->persist($entity);
In my persistence services, which I am already calling. However, doctrine doesn't work as expected. Here are my entities.
Entity/Employee.php
<?php
namespace AppBundle\Entity;
use Doctrine\ORM\Mapping AS ORM;
/**
* #ORM\Entity
* #ORM\Table(uniqueConstraints={#ORM\UniqueConstraint(
* name="UNIQ_EMPLOYEE_ID_NAME_ADDRESS_STATE_CITY_COUNTRY",
* columns={"id","name","city","state","country"}
* )})
*/
class Employee
{
/**
* #ORM\Id
* #ORM\Column(type="integer", options={"unsigned":true})
* #ORM\GeneratedValue(strategy="NONE")
*/
private $id;
/**
* #ORM\Column(type="string", length=255, nullable=false)
*/
private $name;
/**
* #ORM\Column(type="text", nullable=false)
*/
private $address;
/**
* #ORM\Column(type="string", length=255, nullable=false)
*/
private $city;
/**
* #ORM\Column(type="string", length=255, nullable=false)
*/
private $state;
/**
* #ORM\Column(type="string", length=255, nullable=false)
*/
private $country;
/**
* #ORM\ManyToOne(targetEntity="AppBundle\Entity\Department", inversedBy="employee", cascade={"remove","persist"})
* #ORM\JoinColumn(name="department_id", referencedColumnName="id", nullable=false)
*/
private $department;
/**
* #ORM\OneToMany(targetEntity="AppBundle\Entity\Transfer", mappedBy="employee", cascade={"remove","persist"})
*/
private $transfer;
}
?>
Entity/Department.php
<?php
namespace AppBundle\Entity;
use Doctrine\ORM\Mapping AS ORM;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;
use Doctrine\Common\Collections\Selectable;
/**
* #ORM\Entity
* #ORM\Table(uniqueConstraints={#ORM\UniqueConstraint(
* name="UNIQ_DEPARTMENT_ID_NAME",
* columns={"id","name"}
* )})
*/
class Department
{
/**
* #ORM\Id
* #ORM\Column(type="integer", options={"unsigned":true})
* #ORM\GeneratedValue(strategy="NONE")
*/
private $id;
/**
* #ORM\Column(type="string", length=255, nullable=false)
*/
private $name;
/**
* #ORM\OneToMany(targetEntity="AppBundle\Entity\Employee", mappedBy="department", cascade={"remove","persist"})
*/
private $employee;
/**
* #ORM\OneToMany(targetEntity="AppBundle\Entity\Transfer", mappedBy="department", cascade={"remove","persist"})
*/
private $transfer;
}
?>
Entity/Transfer.php
<?php
namespace AppBundle\Entity;
use Doctrine\ORM\Mapping AS ORM;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;
use Doctrine\Common\Collections\Selectable;
/**
* #ORM\Entity
* #ORM\Table(uniqueConstraints={#ORM\UniqueConstraint(
* name="UNIQ_TRANSFER_ID_DEPARTMENT_EMPLOYEE_START_END",
* columns={"id","name"}
* )})
*/
class Transfer
{
/**
* #ORM\Id
* #ORM\Column(type="integer", options={"unsigned":true})
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #ORM\Column(type="date", length=255, nullable=false)
*/
private $start;
/**
* #ORM\Column(type="date", length=255, nullable=false)
*/
private $end;
/**
* #ORM\ManyToOne(targetEntity="AppBundle\Entity\Employee", inversedBy="attendance", cascade={"persist","remove"})
* #ORM\JoinColumn(name="employee_id", referencedColumnName="id", nullable=false)
*/
private $employee;
/**
* #ORM\ManyToOne(targetEntity="AppBundle\Entity\Department", inversedBy="attendance", cascade={"persist","remove"})
* #ORM\JoinColumn(name="department_id", referencedColumnName="id", nullable=false)
*/
private $department;
}
?>
UPDATE 1:
Now, I have another problem. Since my GeneratorValue strategy for Employee and Department are NONE, I have problem with duplicate record error. I am trying to use PreFlushEventArgs to remove the entity before persisting if the record exists in database. But I wonder if it should be that complex?
Thanks for your help in advance.

Answer 1

It seems you cascade persist operation from Employee to Department and Transfer. But they do cascade the persist operation to the Employee Entity too.
It means when you do
$em->persist($an_employee);
You are stuck in a persist loop.
In my opinion, the cascade persist should be only in one way, i.e. only on the Employee entity.
Also if you choose to do this, add your Department to the Employee, and not the opposite :
$an_employee->addDepartment($a_department);
$an_employee->addTransfer($a_transfer);
That way, when you persist an employee, its Departments and Transfer should be persisted too