与Doctrine2（Symfony2）的内部联接

Question

I am new to Symfony2 (~ 1 week). I have a manyToOne on the BudgetData Entity that joins the id of the Entity BudgetDescription. I created a SQL query that I want to replicate for Doctrine :

SELECT d, e
FROM BudgetData d
INNER JOIN BudgetDescription e 
ON d.budgetDescription_id = e.id

BudgetData table : id, year, value, budgetDescription_id (FK)

BudgetDescription table : id, descriptionName

What I tried so far :

    $em = $this->getDoctrine()->getManager();
    $qb = $em->getRepository('MainBundle:BudgetData');
    $qb = $em->createQueryBuilder('d');

    $dataQuery = $qb->select('d, c')
                    ->innerJoin('c.id', 'c', Join::ON, 'd.budgetDescription_id = c.id')
                    ->getQuery();

    $dataQuery = $dataQuery->getArrayResult();

Any idea how I can do the SQL query but in DQL ?

Thank you !

Answer 1

if you have a relation in your BudgetDataEntity called budgetDescription with an attribute $budgetDescription, in the BudgetDataRepository you could do :

    public function myInnerJoin()
    {

           $qb = $this->createQueryBuilder('f') 
                ->select('f','g')
                ->innerJoin('f.budgetDescription', 'g'); 

           return $qb->getQuery()->getArrayResult();
    }

and in controller

$repository = $this->getDoctrine()->getManager()->getRepository('AcmeBundle:BudgetData');
$result = $repository->myInnerJoin(); 

That is my guess

Answer 2

The better solution is to leverage the benefits of the Doctrine ORM. In a nutshell, create entity classes with the proper associations defined and then, as necessary, create custom query methods in the entity's repository class to do your lookups. Example:

The BudgetData entity:

use Doctrine\ORM\Mapping as ORM;
use MainBundle\Entity\BudgetDescription;

...

/**
 * @ORM\Table(name="budget_data")
 * @ORM\Entity(repositoryClass="MainBundle\Repository\BudgetDataRepository")
 */
class BudgetData
{
    // properties here

    /**
     * @ORM\ManyToOne(targetEntity="BudgetDescription")
     * @ORM\JoinColumn(name="category", referencedColumnName="id", nullable=false)
     */
    private $budgetDescription;

    ...

    /**
     * Set budgetDescription
     *
     * @param BudgetDescription $budgetDescription
     * @return BudgetData
     */
    public function setBudgetDescription(BudgetDescription $budgetDescription)
    {
        $this->budgetDescription = $budgetDescription;

        return $this;
    }

    /**
     * Get budgetDescription
     *
     * @return BudgetDescription
     */
    public function getBudgetDescription()
    {
        return $this->budgetDescription;
    }
}

The BudgetDescription entity:

use Doctrine\ORM\Mapping as ORM;

...

/**
 * @ORM\Table(name="budget_description")
 * @ORM\Entity
 */
class BudgetDescription
{
    // properties here
    ...

    /**
     * @ORM\Id
     * @ORM\Column(name="id", type="integer")
     * @ORM\GeneratedValue(strategy="IDENTITY")

     */
    private $id;

    ...
}

Now Doctrine will manage this association for you so that all you need to do to get the BudgetDescription entity from BudgetData is to call the getBudgetDescription() method of a BudgetData instance, like this:

$budgetData = $em->getRepository('MainBundle:BudgetData')->findOneById(3);
$budgetDescription = $budgetData->getBudgetDescription();

And voila. In the above example, Doctrine retrieves a budget_data row with ID=3 in your database and hydrates a BudgetData entity with that data. And then when you call the getBudgetDescription() method, it fetches the associated row in the budget_description table and hydrates a BudgetDescription entity. You can eliminate that second look up by using fetch="EAGER" in your association annotation. By default though, Doctrine lazy loads data so it only loads what you need.

I hope this helps.

ps I would recommend prefixing your primary and foreign key's with the names of the tables. So in the example above, your budget_data table would have a foreign key budget_description_id and your budget_description table would have a primary key budget_description_id . There are many good reasons for doing this not the least of which is clarity of associations between tables.

Answer 3

I used a simple query. The following code works, but if you have any other (better) solution, I would love to have it.

$em = $this->getDoctrine()->getManager();

$qb = $em->createQuery("SELECT d.year, d.value, e.descriptionName FROM MainBundle:BudgetData d INNER JOIN MainBundle:BudgetDescription e WITH d.category = e.id");

$newQuery = $qb->getArrayResult();