Symfony2 database query method using Doctrine instance summary _ php instance

This article mainly introduces the database query method using Doctrine in Symfony2, and summarizes and analyzes the basic query, DQL and query generator implementation methods based on Doctrine in combination with the instance form, for more information about how to use Doctrine to query databases, see the example in this article. We will share this with you for your reference. The details are as follows:

Variables used in the predefined text:

$em = $this->getDoctrine()->getEntityManager();$repository = $em->getRepository('AcmeStoreBundle:Product')

1. Basic Methods

$repository->find($id);$repository->findAll();$repository->findOneByName('Foo');$repository->findAllOrderedByName();$repository->findOneBy(array('name' => 'foo', 'price' => 19.99));$repository->findBy(array('name' => 'foo'),array('price' => 'ASC'));

2. DQL

$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();

Note:

(1) to obtain a result, you can use:

$product = $query->getSingleResult();

To use the getSingleResult () method, you need to wrap it with a try catch statement to ensure that only one result is returned. The example is as follows:

->setMaxResults(1);try {$product = $query->getSingleResult();} catch (\Doctrine\Orm\NoResultException $e) {$product = null;}

(2) setParameter ('price', '19. 99 '). This external method is used to set the "Placeholder" price value in the query statement, instead of directly writing the value into the query statement, which helps prevent SQL injection attacks, you can also set multiple parameters:

->setParameters(array('price' => '19.99′,'name' => 'Foo',))

3. Query Builder using Doctrine

$query = $repository->createQueryBuilder('p')->where('p.price > :price')->setParameter('price', '19.99′)->orderBy('p.price', 'ASC')->getQuery();$products = $query->getResult();

I hope this article will help you design PHP programs based on the Symfony framework.