How to prevent redundant lookups when joining entity relationships? - php

Question

I'm getting up to speed with Symfony 2 and Doctrine and having difficulties with the number of unnecessary database lookups being performed to hydrate with joined entities.
After performing a joined query with a child object, the child is automatically pulling its other mappings from the database. It's doing this despite that I'm not attempting to access any of its properties. It's as if they're being accessed inside the find query.
My example looks like the below - There are entities called Person and Building that both join an entity called Place:
class Person {
/**
* Where this person lives
* #var Place $Home
*
* #ORM\OneToOne(targetEntity="Place", cascade={"persist"}, inversedBy="Resident" )
* #ORM\JoinColumn(name="place_id", referencedColumnName="id")
*/
private $Home;
}
class Building {
/**
* Where this building stands
* #var Place $Site
*
* #ORM\OneToOne(targetEntity="Place", cascade={"persist"}, inversedBy="Landmark" )
* #ORM\JoinColumn(name="place_id", referencedColumnName="id")
*/
private $Site;
}
class Place {
/**
* Reverse mapping
* #var Person $Resident
*
* #ORM\OneToOne(targetEntity="Person", mappedBy="Home")
*/
private $Resident;
/**
* Reverse mapping
* #var Building $Landmark
*
* #ORM\OneToOne(targetEntity="Building", mappedBy="Site")
*/
private $Landmark;
}
My Person repository join looks like this:
/**
* #override
* #return Person
*/
public function find( $id ){
$query = $this->getEntityManager()
->createQuery('
SELECT p, h
FROM MyBundle:Person p
JOIN p.Home h
WHERE p.id = :id'
)->setParameter('id', $id);
return $query->getSingleResult();
}
How can I prevent the Place fetching its Building relationship separately during the find operation? Is there something I can pass into the Query instance to stop this?

Answer 1

add fetch option to your mapping.
Like so:
class Place {
/**
* Reverse mapping
* #var Person
*
* #ORM\OneToOne(targetEntity="Person", mappedBy="Home", fetch="EXTRA_LAZY")
*/
private $Resident;
}