Symfony 2 fetch data from many to many relationship with doctrine

Question

I'm stuck on getting this to work with Symfony2 and Doctrine, the situation: A page with piercing info (general info and caretaking info).

A care taking can have multiple piercings to which it applies and a piercing can have multiple care takings

Database layout:

Piercings:
    id
    name
    ...

Caretaking:
    id
    title
    description

piercing_to_caretaking
    id
    piercing_id
    caretaking_id

Now, how would I create the Entity and the corresponding Query/Dql ?

Answer 1

If you are defining your entities using yml:

In Piercing.orm.yml add:

manyToMany:
    caretakings:
        targetEntity: Caretaking
        inversedBy: piercings
        joinTable:
            name: piercing_caretaking
            joinColumns:
                caretaking:
                    referencedColumnName: id
            inverseJoinColumns:
                piercing:
                    referencedColumnName: id

In Caretaking.orm.yml add:

manyToMany:
    piercings:
      targetEntity: Piercing
      mappedBy: caretakings

Generate/update the entities in the usual way, i.e.:

app/console doctrine:schema:update --dump-sql (to check results)
app/console doctrine:schema:update --force (to apply changes)

Then when you have a Piercing or Caretaking entity you can access the related entities like this:

$piercing->addCaretaking($caretaking); 
$caretakings = $piercing->getCaretakings();
...
$piercings = $caretaking->getPiercings();

For more information, including how to do this using annotations, see sub-section 5.1.4 Many to Many, Bidirectional in Section 5 Association Mapping of the Doctrine documentation.