Question

Let’s say I have a schema where User has many Alerts (many to many).

Alert:
  columns: ~

User:
  columns: ~
  relations:
    Alerts:
      class: Alert
      refClass: UserAlert
      local: user_id
      foreign: alert_id

UserAlert:
  columns:
    user_id:
      type: integer(4)
      primary: true
    alert_id:
      type: integer(4)
      primary: true
    active:
      type: boolean
      notnull: true
      default: true
  relations:
    Alert:
      local: alert_id
      foreign: id
    User:
      local: user_id
      foreign: id

Notice a custom active field in the ref class which tells if related alert is active for the user. How do I fetch a user with his active alerts?

UPDATE:
One way to achieve this is to override join condition with WITH keyword:

$user = UserTable::createQuery('u')
      ->createQuery('u')
      ->leftJoin('u.UserAlert aa WITH aa.enabled = ?', array(true))
      ->leftJoin('aa.Alert a')
      ->addWhere('u.id = ?', $id)
      ->fetchOne();

But this way you would have to call $user->getUserAlert() which returns a collection of ref class objects. I would like to have a ‘alerts’ relation populated, so that I could call $user->getAlerts() directly.

Answer 1

First, your schema is wrong (at least, it doesn’t work on my side). Here is the correct one (I put some field in User and Alert for test):

Alert:
  columns:
    name: string(30)
  relations:
    Users:
      class: User
      local: alert_id
      foreign: user_id
      refClass: UserAlert
      foreignAlias: Alerts

User:
  columns:
    name: string(255)
  relations:
    Alerts:
      class: Alert
      local: user_id
      foreign: alert_id
      refClass: UserAlert
      foreignAlias: Users

UserAlert:
  columns:
    user_id:
      type: integer
      primary: true
    alert_id:
      type: integer
      primary: true
    active:
      type: boolean
  relations:
    User:
      class: User
      local: user_id
    Alert:
      class: Alert
      local: alert_id

You have to define your many2many realtion in both Alert, User and UserAlert.

Then I build the db and put some data inside, for the test: http://sqlfiddle.com/#!2/dd507/2

Now, to retrieve all users with only their active alerts, put this in your UserTable.php

public function retrieveAlerts($active = true)
{
  $q = $this->createQuery('u')
    ->leftJoin('u.UserAlert ua')
    ->leftJoin('ua.Alert a')
    ->where('ua.active = ?', array($active));

  return $q->fetchArray();
}

And then, in your action, simply do that:

$users = Doctrine_Core::getTable('User')->retrieveAlerts();

If you print_r your results, you will see that we retrieve users 3 and 4 with their active alerts:

Array
(
  [0] => Array
    (
      [id] => 3
      [name] => tata
      [UserAlert] => Array
        (
          [0] => Array
            (
              [user_id] => 3
              [alert_id] => 1
              [active] => 1
              [Alert] => Array
                (
                  [id] => 1
                  [name] => new
                )
            )
          [1] => Array
            (
              [user_id] => 3
              [alert_id] => 2
              [active] => 1
              [Alert] => Array
                (
                  [id] => 2
                  [name] => fired
                )
            )
        )
    )
  [1] => Array
    (
      [id] => 4
      [name] => tutu
      [UserAlert] => Array
        (
          [0] => Array
            (
              [user_id] => 4
              [alert_id] => 3
              [active] => 1
              [Alert] => Array
                (
                  [id] => 3
                  [name] => sold
                )
            )
        )
    )
)