Example of a OneToMany Relationship in Doctrine.

Doctrine-OneToMany.php

<?php
/** @Entity */
class User
{
    /** @Id @GeneratedValue @Column(type="string") */
    private $id;

    /**
     * Bidirectional - One-To-Many (INVERSE SIDE)
     *
     * @OneToMany(targetEntity="Comment", mappedBy="author")
     */
    private $commentsAuthored;

    public function getCommentsAuthored() {
        return $this->commentsAuthored->toArray();
    }

    public function setCommentsAuthored($comments) {
        $this->commentsAuthored->clear();
        foreach ($comments as $comment) {
            $this->addComment($comment);
        }

        return $this;
    }

    public function addComment(Comment $comment) {
        
        // other events listening to the adding of a comment go here.

        $this->commentsAuthored[] = $comment;
        $comment->setAuthor($this);

        return $this;
    }

    public function removeComment(Comment $comment) {
        if ($this->commentsAuthored->removeElement($comment)) {
            $comment->setAuthor(null);
        }
    }
}

/** @Entity */
class Comment
{
    /** @Id @GeneratedValue @Column(type="string") */
    private $id;

    /**
     * Bidirectional - Many Comments are authored by one user (OWNING SIDE)
     *
     * @ManyToOne(targetEntity="User", inversedBy="commentsAuthored")
     */
    private $author;

    public function setAuthor(User $author = null) {
        $this->author = $author;

        return $this;
    }
}