如何在symfony2中添加不在数据库中的子文件

Question

I have a school table. which contains a parent_school_id for parent school.

But in form I need to add two filed 1) for parent school 2) for child school.

for parent school it work in entity by following code of entity :

/**
 * @ORM\Column(name="parent_school_id",type="integer", nullable=true)
 * @ORM\OneToOne(targetEntity="School", mappedBy="id")
 */
protected $parentSchool;

now I add a child school but it is not in db so i added follow code :

/**
 * @OneToOne(targetEntity="School")
 * @JoinColumn(name="child_school_id", referencedColumnName="id")
 */
protected $childSchool;

it give me following error ::

[Semantical Error] The annotation "@OneToOne" in property Epx\Bundle\CourseBundle\Entity\School::$childSchool was never imported. Did you maybe forget to add a "use" statement for this annotation? 

How can I add this extra filed without db field ?

Answer 1

It works when I put this code :

/**
 * @ORM\OneToOne(targetEntity="School", mappedBy="parentSchool")
 */
protected $childSchool;
/**
 * @ORM\ManyToOne(targetEntity="School", inversedBy="childSchool")
 * @ORM\JoinColumn(name="parent_school_id", referencedColumnName="id")
 */
protected $parentSchool;