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09.

Querying on a Relationship

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We need to create a query that returns the GenusNotes that belong to a specific Genus and are less than 3 months old. To keep things organize, custom queries to the GenusNote table should live in a GenusNoteRepository. Ah, but we don't have one yet! No problem: copy GenusRepository.php to GenusNoteRepository.php, rename the class and clear it out:

22 lines | src/AppBundle/Repository/GenusNoteRepository.php
// ... lines 1 - 2
namespace AppBundle\Repository;
// ... lines 4 - 6
use Doctrine\ORM\EntityRepository;
class GenusNoteRepository extends EntityRepository
{
// ... lines 11 - 20
}

Add a new public function findAllRecentNotesForGenus() and give this a Genus argument:

22 lines | src/AppBundle/Repository/GenusNoteRepository.php
// ... lines 1 - 8
class GenusNoteRepository extends EntityRepository
{
/**
* @param Genus $genus
* @return GenusNote[]
*/
public function findAllRecentNotesForGenus(Genus $genus)
{
// ... lines 17 - 19
}
}

Excellent! And just like before - start with return $this->createQueryBuilder() with genus_note as a query alias. For now, don't add anything else: finish with the standard ->getQuery() and ->execute():

22 lines | src/AppBundle/Repository/GenusNoteRepository.php
// ... lines 1 - 8
class GenusNoteRepository extends EntityRepository
{
// ... lines 11 - 14
public function findAllRecentNotesForGenus(Genus $genus)
{
return $this->createQueryBuilder('genus_note')
->getQuery()
->execute();
}
}

Doctrine doesn't know about this new repository class yet, so go tell it! In GenusNote, find @ORM\Entity and add repositoryClass="AppBundle\Repository\GenusNoteRepository":

101 lines | src/AppBundle/Entity/GenusNote.php
// ... lines 1 - 6
/**
* @ORM\Entity(repositoryClass="AppBundle\Repository\GenusNoteRepository")
* @ORM\Table(name="genus_note")
*/
class GenusNote
{
// ... lines 13 - 99
}

Finally, use the new method in GenusController - $recentNotes = $em->getRepository('AppBundle:GenusNote')->findAllRecentNotesForGenus() and pass it the $genus object from above:

120 lines | src/AppBundle/Controller/GenusController.php
// ... lines 1 - 12
class GenusController extends Controller
{
// ... lines 15 - 57
public function showAction($genusName)
{
// ... lines 60 - 85
$recentNotes = $em->getRepository('AppBundle:GenusNote')
->findAllRecentNotesForGenus($genus);
// ... lines 88 - 92
}
// ... lines 94 - 118
}

Obviously, we're not done yet - but it should at least not break. Refresh. Ok, 100 recent comments - that's perfect: it's returning everything. Oh, you know what isn't perfect? My lame typo - change that to the word Recent. Embarrassing for me:

42 lines | app/Resources/views/genus/show.html.twig
// ... lines 1 - 4
{% block body %}
<h2 class="genus-name">{{ genus.name }}</h2>
<div class="sea-creature-container">
<div class="genus-photo"></div>
<div class="genus-details">
<dl class="genus-details-list">
// ... lines 12 - 17
<dt>Recent Notes</dt>
// ... line 19
</dl>
</div>
</div>
<div id="js-notes-wrapper"></div>
{% endblock %}
// ... lines 25 - 42

Using the Relationship in the Query

Head back to the repository. This query is pretty simple actually: add an ->andWhere('genus_note.genus = :genus'). Then, fill in :genus with ->setParameter('genus', $genus):

27 lines | src/AppBundle/Repository/GenusNoteRepository.php
// ... lines 1 - 8
class GenusNoteRepository extends EntityRepository
{
// ... lines 11 - 14
public function findAllRecentNotesForGenus(Genus $genus)
{
return $this->createQueryBuilder('genus_note')
->andWhere('genus_note.genus = :genus')
->setParameter('genus', $genus)
// ... lines 20 - 22
->getQuery()
->execute();
}
}

This a simple query - equivalent to SELECT * FROM genus_note WHERE genus_id = some number. The only tricky part is that the andWhere() is done on the genus property - not the genus_id column: you always reference property names with Doctrine.

Finish this with another andWhere('genus_note.createdAt > :recentDate') and ->setParameter('recentDate', new \DateTime('-3 months')):

27 lines | src/AppBundle/Repository/GenusNoteRepository.php
// ... lines 1 - 8
class GenusNoteRepository extends EntityRepository
{
// ... lines 11 - 14
public function findAllRecentNotesForGenus(Genus $genus)
{
return $this->createQueryBuilder('genus_note')
->andWhere('genus_note.genus = :genus')
->setParameter('genus', $genus)
->andWhere('genus_note.createdAt > :recentDate')
->setParameter('recentDate', new \DateTime('-3 months'))
// ... line 22
->getQuery()
->execute();
}
}

Perfect! Go back and try it - the count should go back to 6. There we go! But now, instead of fetching all the notes just to count some of them, we're only querying for the ones we need. And, Doctrine loves returning objects, but you could make this even faster by returning only the count from the query, instead of the objects. Don't optimize too early - but when you're ready, we cover that in our Going Pro with Doctrine Queries.