原则2.1-OneToMany关系，数据下载

Question

I have two classes:

User :

/** @Entity @Table(name="users") */
class User {
    /**
     * @Id @GeneratedValue @Column(type="integer")
     * @var integer
     */
    protected $id;

    /**
     * @Column(type="string", length=20, unique=TRUE)
     * @var string
     */
    protected $login;

    /**
     * @OneToMany(targetEntity="News", mappedBy="author")
     */
    protected $news;    

    public function __construct() {
        $this->news = new \Doctrine\Common\Collections\ArrayCollection;
    }
}

and News :

/** @Entity @Table(name="news") */
class News {
    /**
     * @Id @GeneratedValue @Column(type="integer")
     * @var integer
     */
    protected $id;

    /**
     * @Column(type="string", length=100)
     * @var string
     */
    protected $title;

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

    /**
     * @ManyToOne(targetEntity="User", inversedBy="news")
     * @JoinColumn(referencedColumnName="id")
     */ 
    protected $author;
}

When I will make this code

$q = $this->db->createQuery('SELECT u FROM User u WHERE u.id = '.$id);
$user = $q->getSingleResult();

does the Doctrine will download all news (created by particular user) from database?

Answer 1

It won't until you request a user's news by calling the news accessor method. If you rewrite your query as

SELECT u, n FROM User u JOIN u.news n

Then a user and his news will be all returned as the result.

You can also check the query generated by doctrine using a logger:

$config->setSQLLogger(new Doctrine\DBAL\Logging\EchoSQLLogger);

PS: never do this: u.id = '.$id in queries to avoid sql injections. Instead, use placeholders:

$q = $this->db->createQuery('SELECT u FROM User u WHERE u.id = :id');
$q->setParameter('id', $id);