Doctrine: complicated select with two ManyToMany relationships - doctrine-orm

Question

I need to query a number of issues in a table of a issue tracking system limiting this query by a complicated condition:
Issues (Entity) are grouped into categories (another Entity). Persons (Entity) are members of multiple roles (fourth Entity), this is one ManyToMany relationship. And finally, a role can have access on one or many categories, this is the second ManyToMany relationship.
<?php
/**
* #Entity
* #Table(name="issue")
*/
class Issue
{
/**
* #ManyToOne(targetEntity="Category", fetch="EAGER")
* #JoinColumn(name="category", referencedColumnName="id", onDelete="RESTRICT", nullable=false)
*/
private $category;
…
}
/**
* #Entity
* #Table(name="category")
*/
class Category
{
/**
* #ManyToMany(targetEntity="Role", mappedBy="categories")
*/
private $roles;
…
}
/**
* #Entity
* #Table(name="role")
*/
class Role
{
/**
* #ManyToMany(targetEntity="Person", mappedBy="roles")
*/
private $persons;
/**
* #ManyToMany(targetEntity="Category", inversedBy="roles")
* #JoinTable(name="role_has_access_on_category",
* joinColumns={#JoinColumn(name="role_id", referencedColumnName="id")},
* inverseJoinColumns={#JoinColumn(name="category_id", referencedColumnName="id")}
* )
*/
private $categories;
…
}
/**
* #Entity
* #Table(name="person")
*/
class Person
{
/**
* #ManyToMany(targetEntity="Role", inversedBy="persons")
* #JoinTable(name="person_is_member_of_role",
* joinColumns={#JoinColumn(name="person_id", referencedColumnName="id")},
* inverseJoinColumns={#JoinColumn(name="role_id", referencedColumnName="id")})
*/
private $roles;
…
}
I have left all fields except the relationship ones away, of course there are primary keys and a lot more columns there…
I want to retrieve all issues that belong to categories to which a person with a given primary key has access via the roles it is member of.
At first I just started to experiment how to query ManyToMany relationships, so the code below does not really resemble my target.
I have finally found out how I can get the query to retrieve the other side of one ManyToMany relationship, so I can already get the roles a person belongs to. But this query does not fetch the categories a role has access to.
$qb = $this->em->createQueryBuilder();
$qb->select('person')
->addSelect('role')
->addSelect('category')
->from('Person', 'person')
->innerJoin('person.roles', 'role')
->innerJoin('role.categories', 'category');
$result = $qb->getQuery()->getResult();
$result contains the persons data with all associated roles, but a blank array of categories instead of the entities. The final query would start from the issue side of course, but for now I would only like to get through to the other side…
So now I wonder whether I have to take all the roles and loop through them to fetch all categories. Is there no easier Doctrine way?
By the way, that's the SQL I would use:
SELECT issue.* FROM person AS p, person_is_member_of_role AS pim, role_has_access_on_category AS rha, issue
WHERE
p.id = pim.person_id AND
pim.role_id = rha.role_id AND
rha.category_id = todo.category AND
p.id = ?;
I hope this all makes it clear somehow, otherwise I will revise my question…

Answer 1

You are over-complicating it by trying to put all join conditions in the WHERE clause.
If I understood the question correctly, the query looks like this:
SELECT
i
FROM
Issue i
JOIN
i.category c
JOIN
c.roles r
JOIN
r.persons p
WHERE
p.id = :personId
Translated in QueryBuilder API:
$qb = $entityManager->createQueryBuilder();
$issues = $qb
->select('i')
->from('Issue', 'i')
->innerJoin('i.category', 'c')
->innerJoin('c.roles', 'r')
->innerJoin('r.persons', 'p')
->andWhere($qb->expr()->eq('p.id', ':personId'))
->setParameter('personId', $personId)
->getQuery()
->getResult();
Also, consider avoiding the QueryBuilder if there's no good reason to use it. After all, it's just a string builder.