Doctrine_Entity_ManyToMany_directional.php

<?php
// Epost.php
use Doctrine\Common\Collections\ArrayCollection;
/**
* @Entity @Table(name="e_post", options={"collate"="utf8_general_ci"})
*/
class Epost
{
	/**
	* @Id @GeneratedValue @Column(type="integer")
	* @var int
	*/
	protected $id;

	public function getId() { return $this->id; }

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

	/**
	 * @var Etags[]|ArrayCollection
	 * @ManyToMany(targetEntity="Etag", inversedBy="eposts")
	 * @JoinTable(name="e_posts_tags")
	 * @JoinColumn(name="epost_id", referencedColumnName="id", onDelete="CASCADE")
	 */
	protected $etags;

	public function getEtags() { return $this->etags; }

	/**
	 * @var string
	 * @Column(type="string", name="post_title", length=128)
	 */
	protected $title;

	public function getTitle() { return $this->title; }
	public function setTitle($title) { $this->title = $title; return $this; }

	/**
	 * @var string
	 * @Column(type="text", name="post_content")
	 */
	protected $content;

	public function getContent() { return $this->content; }
	public function setContent($content) { $this->content = $content; return $this; }

	public function addEtag(Etag $etag)
	{
		if ($this->etags->contains($etag)) return;
		$this->etags->add($etag);
		$etag->addEpost($this); // for 双向
	}

	public function removeEtag(Etag $etag)
	{
		if (!$this->etags->contains($etag)) return;
		$this->etags->removeElement($etag);
		$etag->removeEpost($this); // for 双向
	}
}

// Etag.php
use Doctrine\Common\Collections\ArrayCollection;
/**
* @Entity @Table(name="e_tags", options={"collate"="utf8_general_ci"})
*/
class Etag
{
	/**
	* @Id @GeneratedValue @Column(type="integer")
	* @var int
	*/
	protected $id;

	public function getId() { return $this->id; }

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

	/**
	 * @var Epost[]|ArrayCollection
	 * @ManyToMany(targetEntity="Epost", mappedBy="etags")
	 * @JoinColumn(name="etag_id", referencedColumnName="id", onDelete="CASCADE")
	 */
	protected $eposts;

	public function getEposts() { return $this->eposts; }

	
	/**
	 * @var string
	 * @Column(type="string", name="tag_name", length=128)
	 */
	protected $name;
	 
	public function getName() { return $this->name; }
	public function setName($name) { $this->name = $name; return $this; }

	public function addEpost(Epost $epost)
	{
		if ($this->eposts->contains($epost)) return;
		$this->eposts->add($epost);
		$epost->addEtag($this);
	}

	public function removeEpost(Epost $epost)
	{
		if (!$this->eposts->contains($epost)) return;
		$this->eposts->removeElement($epost);
		$epost->removeEtag($this); 
	}
}