Confused using DQL with Doctrine2 entities and Zend framework - zend-framework

Question

I have 4 entities : Country, Region, Province, Town.
<?php
namespace Entities;
use Doctrine\Common\Collections\ArrayCollection;
/**
* #Entity (repositoryClass="Repositories\Region")
* #Table(name="regions")
* #HasLifecycleCallbacks
*/
class Region {
/**
* #Id #Column(type="integer")
* #GeneratedValue(strategy="AUTO")
*/
private $id;
/** #Column(type="string", length=30,unique=TRUE) */
private $regionname;
/** #Column(type="boolean") */
private $active;
/**
* #ManyToOne(targetEntity="Country", inversedBy="regions")
* #JoinColumn(name="countries_id", referencedColumnName="id",nullable=FALSE)
*/
private $countries_id;
/**
* #OneToMany(targetEntity="Province", mappedBy="provinces")
*/
private $provinces;
public function __construct() {
$this->provinces = new ArrayCollection();
$this->active = true;
}
<?php
namespace Entities;
use Doctrine\Common\Collections\ArrayCollection;
/**
* #Entity (repositoryClass="Repositories\Province")
* #Table(name="provinces")
* #HasLifecycleCallbacks
*/
class Province {
/**
* #Id #Column(type="integer")
* #GeneratedValue(strategy="AUTO")
*/
private $id;
/** #Column(type="string", length=30,unique=TRUE) */
private $provincename;
/** #Column(type="boolean") */
private $active;
/**
* #ManyToOne(targetEntity="Region", inversedBy="provinces")
* #JoinColumn(name="regions_id", referencedColumnName="id",nullable=FALSE)
*/
private $regions_id;
/**
* #OneToMany(targetEntity="Town", mappedBy="towns")
*/
private $towns;
public function __construct() {
$this->towns = new ArrayCollection();
$this->active = true;
}
<?php
namespace Entities;
use Doctrine\Common\Collections\ArrayCollection;
/**
* #Entity (repositoryClass="Repositories\Town")
* #Table(name="towns")
* #HasLifecycleCallbacks
*/
class Town {
/**
* #Id #Column(type="integer")
* #GeneratedValue(strategy="AUTO")
*/
private $id;
/** #Column(type="string", length=30,unique=FALSE) */
private $townname;
/** #Column(type="boolean") */
private $active;
// so that we know when a user has added a town
/** #Column(type="boolean") */
private $verified;
/**
* #OneToMany(targetEntity="User", mappedBy="users")
*/
private $users;
/**
* #ManyToOne(targetEntity="Province", inversedBy="towns")
* #JoinColumn(name="provinces_id", referencedColumnName="id",nullable=FALSE)
*/
private $provinces_id;
public function __construct() {
$this->users = new ArrayCollection();
$this->active = true;
}
I want to create a query using DQL that will give me a list of towns for a given region.
To get a simple list of active towns I am using :
public function findActiveTowns($provinces_id = null)
// we can pass in a specific provinces_id if we want
{
$qb = $this->_em->createQueryBuilder();
$qb->select('a.townname, a.id')
->from('Entities\Town', 'a');
if (!is_null($provinces_id)){
$qb->where('a.provinces_id = :provinces_id AND a.active = TRUE')
->setParameter('provinces_id', $provinces_id);
} else {
$qb->where('a.active = TRUE');
}
$towns=$qb->getQuery()->getResult();
// make pairs array suitable for select lists
$options = array();
foreach ($towns as $key => $value) {
$options[$value['id']] = $value['townname'];
}
return $options;
}
Now, to get to the point. How do I set up the joins and get this working so that we can pass in a region_id and return all of the towns in the region.
In native SQL I'd do something like this :
SELECT towns.id
FROM `towns`
INNER JOIN `provinces`
INNER JOIN `regions`
WHERE regions.id =1
Thanks.

Answer 1

A few things first.
Don't name your fields with _id, because they are not identifiers, but relations to other objects. Join column annotation goes with the real DB name, field in object model go without.
Write/generate get/set/add methods for all fields to encapsulate them, so u can actually use them. You can't read private fields from "the outside".
As for you question, haven't tested it, but something like this should work.
class Town {
/**
* #ManyToOne(targetEntity="Province", inversedBy="towns")
* #JoinColumn(name="provinces_id", referencedColumnName="id",nullable=FALSE)
*/
private $province;
class Province {
/**
* #ManyToOne(targetEntity="Region", inversedBy="provinces")
* #JoinColumn(name="regions_id", referencedColumnName="id",nullable=FALSE)
*/
private $region;
$qb->select('a.townname, a.id')
->from('Entities\Town', 'a')
->leftJoin('a.province', 'p');
if (!is_null($provinces_id) && !is_null($region_id)){
$qb->where('a.province = :province AND a.active = TRUE')
->andWhere('p.region = :region')
->setParameter('province', $provinces_id)
->setParameter('region', $region_id);
} else {
$qb->where('a.active = TRUE');
}