Question

I’m trying to do an association of 5 objects with Doctrine2 (PHP).
I’m using PostgreSQL.

Here is the Database schema:
Database schema

A company may have many Hubs, each Hub have one Harbor.
A company may have many Line, each Line have a Linelist.
A Linelist have 2 Harbors.
For example, a Linelist is “Los Angeles-Seattle”, and multiple companies may own it thanks to the Line table.

I’m trying to query all the Hub, Harbor, Linelist, and Line for one company.
I have the SQL query:

SELECT *
FROM hub h
JOIN harbor a
ON a.id = h.harbor_id
JOIN linelist l
ON (l.harborstart_id = a.id OR l.harborend_id = a.id)
JOIN line m
ON m.linelist_id = l.id
WHERE h.company_id = 41
AND m.company_id = 41"

I’m trying to do the same using DQL.
I tried this, but it doesn’t worked:

$query = $this->getEntityManager()
->createQuery('SELECT h, a, l, m
               FROM AmGameBundle:Hub h
               JOIN h.harbor a
               JOIN a.linelist l
               JOIN l.line m
               WHERE h.company = :company_id
               AND m.company = :company_id')
->setParameter('company_id', $company_id);

As a result, I only have the LineList and Line objects matching harborstart_id, but I want the one matching either harborstart_id or harborend_id.

Do you think this is possible in DQL?
It might be better to change the relation between Harbor and Linelist for a many to many?

Answer 1

I think that’s a matter of defining 2 relations from harbor to linelist in your Entities. I imagine you have something like

<?php
/**
 * @Entity
 * @Table(name="LineList")
 */
class LineList {
    /** 
     * @var object $startHarbor
     * @ManyToOne(targetEntity="Harbor", inversedBy="startHarbors")
     * @JoinColumn(name="harborstart_id", referencedColumnName="id", nullable=FALSE)
     */
    protected $startHarbor;
}

/**
 * @Entity
 * @Table(name="Harbor")
 */
class Harbor {
    /** 
     * @var object $startHarbors
     * @OneToMany(targetEntity="LineList", mappedBy="startHarbor")
     */
    protected $startHarbors;
}

That will let you join Harbors to LineLists via harborstart_id (you named the variable linelist, but I think now it’s better to change the identifiers as there will be 2 referring to the same foreign table), then if you want to harborend_id

<?php
/**
 * @Entity
 * @Table(name="LineList")
 */
class LineList {
    /** 
     * @var object $startHarbor
     * @ManyToOne(targetEntity="Harbor", inversedBy="startHarbors")
     * @JoinColumn(name="harborstart_id", referencedColumnName="id", nullable=FALSE)
     */
    protected $startHarbor;

    /** 
     * @var object $endHarbor
     * @ManyToOne(targetEntity="Harbor", inversedBy="endHarbors")
     * @JoinColumn(name="harborend_id", referencedColumnName="id", nullable=FALSE)
     */
    protected $endHarbor;
}

/**
 * @Entity
 * @Table(name="Harbor")
 */
class Harbor {
    /** 
     * @var object $startHarbors
     * @OneToMany(targetEntity="LineList", mappedBy="startHarbor")
     */
    protected $startHarbors;

    /** 
     * @var object $endHarbors
     * @OneToMany(targetEntity="LineList", mappedBy="endHarbor")
     */
    protected $endHarbors;
}

Now you can change the DQL to:

$query = $this->getEntityManager()
->createQuery('SELECT h, a, sh, eh, m
               FROM AmGameBundle:Hub h
               JOIN h.harbor a
               JOIN a.startHarbors sh
               JOIN a.endHarbors eh
               JOIN l.line m
               WHERE h.company = :company_id
               AND m.company = :company_id')
->setParameter('company_id', $company_id);

That should get you in the right direction. If it becomes troublesome though, a many-to-many approach as you speculated should be a well documented solution.