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Symfony2 – Franz Jordán 2011
Deleting an Object
Deleting an object is very similar, but requires a call to the remove() method of the entity
manager:
$em->remove($product);
$em->flush();
As you might expect, the remove() method notifies Doctrine that you'd like to remove the given
entity from the database. The actual DELETE query, however, isn't actually executed until
the flush()method is called.
Querying for Objects
You've already seen how the repository object allows you to run basic queries without any work:
$repository->find($id);
$repository->findOneByName('Foo');
Of course, Doctrine also allows you to write more complex queries using the Doctrine Query
Language (DQL). DQL is similar to SQL except that you should imagine that you're querying for
one or more objects of an entity class (e.g. Product) instead of querying for rows on a table
(e.g.product).
When querying in Doctrine, you have two options: writing pure Doctrine queries or using
Doctrine's Query Builder.
Querying for Objects with DQL
Imaging that you want to query for products, but only return products that cost more
than 19.99, ordered from cheapest to most expensive. From inside a controller, do the
following:
$em = $this->getDoctrine()->getEntityManager();
$query = $em->createQuery(
'SELECT p FROM AcmeStoreBundle:Product p WHERE p.price > :price ORDER BY p.price ASC'
)->setParameter('price', '19.99');
$products = $query->getResult();
If you're comfortable with SQL, then DQL should feel very natural. The biggest difference is that
you need to think in terms of "objects" instead of rows in a database. For this reason, you
select fromAcmeStoreBundle:Product and then alias it as p.
The getResult() method returns an array of results. If you're querying for just one object, you
can use the getSingleResult() method instead:
$product = $query->getSingleResult();
The getSingleResult() method throws a Doctrine\ORM\NoResultExceptionexception if no
results are returned and aDoctrine\ORM\NonUniqueResultException if more than one
result is returned. If you use this method, you may need to wrap it in a try-catch block and
ensure that only one result is returned (if you're querying on something that could feasibly
return more than one result):
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