Parent Child Relationship With A Single Entity In Doctrine 2

doctrine, doctrine-orm, mysql, php, zend-framework2

Solution

This should work:

<?php

use Doctrine\Common\Collections\ArrayCollection;

/** @ORM\Entity */
class Category {

    /**
     * @ORM\Id
     * @ORM\Column(type="integer", name="id")
     * @ORM\GeneratedValue
     */
    protected $id;

    // ...

    /**
     * @ORM\OneToMany(targetEntity="Category", mappedBy="parent")
     */
    protected $children;

    /**
     * @ORM\ManyToOne(targetEntity="Category", inversedBy="children")
     * @ORM\JoinColumn(name="parent", referencedColumnName="id")
     */
    protected $parent;

    public function __construct() {
        $this->children = new ArrayCollection();
    }

    // Once you have that, accessing the parent and children should be straight forward 
    // (they will be lazy-loaded in this example as soon as you try to access them). IE:

    public function getParent() {
        return $this->parent;
    }

    public function getChildren() {
        return $this->children;
    }

    // ...

    // always use this to setup a new parent/child relationship
    public function addChild(Category $child) {
       $this->children[] = $child;
       $child->setParent($this);
    }

    public function setParent(Category $parent) {
       $this->parent = $parent;
    }

}

Problem

I have database table that looks like this: ``` +----+--------+--------------------+ | id | parent | description | +----+--------+--------------------+ | 1 | null | P Cat 1 | | 2 | 1 | Child 1 of P Cat 1 | | 3 | 1 | Child 2 of P Cat 1 | | 4 | null | P Cat 2 | | 5 | 4 | Child 1 of P Cat 2 | | 6 | 4 | Child 2 of P Cat 2 | +----+--------+--------------------+ ``` How can I create a doctrine 2 entity that has these columns, but I need the parent column to reference the "id" column as a parent. Of course, a parent record has a null "parent" column value. So fair I have ``` <?php namespace MyNamespace; use Doctrine\ORM\Mapping AS ORM; use Doctrine\Common\Collections\ArrayCollection; /** * @ORM\Entity * @ORM\Table(name="category") **/ class Category { /** * @ORM\Id * @ORM\Column(type="integer", name="id") * @ORM\GeneratedValue */ protected $id; /** * Creates a parent / child relationship on this entity. * * @ORM\ManyToOne(targetEntity="MyNamespace\Category",inversedBy="id") * @ORM\JoinColumn(name="FK_parent_id", referencedColumnName="id", nullable=true) */ protected $parent = null; /** * @ORM\Column(type="string", name="description", length=250) * * @var string */ protected $description; /** * Gets the Primary key value. * * @return integer */ public function getId() { return $this->id; } /** * Sets another category ID as the parent of this category. */ public function setParent(Category $category) { $this->parent = $category; } /** * Clears the parent id and makes it null. */ public function clearParent() { $this->parent = null; } /** * Sets the description. * * @param string $description * @return Category */ public function setDescription($description) { $this->description = $description; return $this; } /** * Gets the description value. * * @return string */ public function getDescription() { return $this->description; } } ``` Needless to say, this doesn't appear to work. The questions are: - The setParent() method doesn't appear to work as expected when another entity is added as a parent. - I need a getChildren() method on this entity. How can I achieve that?

Original source