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Symfony2 – Franz Jordán 2011
$query = $em->createQuery('SELECT ....')
->setMaxResults(1);
try {
$product = $query->getSingleResult();
} catch (\Doctrine\Orm\NoResultException $e) {
}
// ...
$product = null;
The DQL syntax is incredibly powerful, allowing you to easily join between entities (the topic
ofrelations will be covered later), group, etc. For more information, see the official
Doctrine Doctrine Query Language documentation.
Setting Parameters
Take note of the setParameter() method. When working with Doctrine, it's always a good idea
to set any external values as "placeholders", which was done in the above query:
... WHERE p.price > :price ...
You can then set the value of the price placeholder by calling the setParameter()method:
->setParameter('price', '19.99')
Using parameters instead of placing values directly in the query string is done to prevent SQL
injection attacks and should always be done. If you're using multiple parameters, you can set
their values at once using the setParameters() method:
->setParameters(array(
'price' => '19.99',
'name' => 'Foo',
))
Using Doctrine's Query Builder
Instead of writing the queries directly, you can alternatively use Doctrine's QueryBuilder to do
the same job using a nice, object-oriented interface. If you use an IDE, you can also take
advantage of auto-completion as you type the method names. From inside a controller:
$repository = $this->getDoctrine()
->getRepository('AcmeStoreBundle:Product');
$query = $repository->createQueryBuilder('p')
->where('p.price > :price')
->setParameter('price', '19.99')
->orderBy('p.price', 'ASC')
->getQuery();
$products = $query->getResult();
The QueryBuilder object contains every method necessary to build your query. By calling
thegetQuery() method, the query builder returns a normal Query object, which is the same
object you built directly in the previous section.
For more information on Doctrine's Query Builder, consult Doctrine's Query
Builder documentation.
Custom Repository Classes
In the previous sections, you began constructing and using more complex queries from inside a
controller. In order to isolate, test and reuse these queries, it's a good idea to create a custom
repository class for your entity and add methods with your query logic there.
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