Propel：如何删除通过多对多关系建立的链接

Question

(link to previous question just in case: Struggling with one-to-many relation in an admin form )

I have this many-to-many relation in my Symfony-1.3 / Propel-1.4 project between User and Partner . When the User is being saved, if it has certain boolean flag being true, I want to clear all the links to the partners. Here is what I do at the moment and it doesn't work:

// inside the User model class
public function save(PropelPDO $con = null) {
  if ($this->getIsBlaBla()) {
    $this->setStringProperty(NULL);
    $this->clearUserPartners();
  }
  parent::save($con);
}

Setting the string property to NULL works; looking at the DB clearly shows it. Thing is however, the USER_PARTNER table still holds the relations between the users and the partners. So I figured I have to clear the links one by one, like this:

foreach($this->getUserPartners() as $user_partner) {
  $user_partner->delete();
  //UserPartnerPeer::doDelete($user_partner); // tried that too
}

Both don't do the trick.

As I mentioned in my previous question, I am just monkey-learning Symfony via trial and error, so I evidently miss something very obvious. Please point me in the right direction!

EDIT: Here is how I made it work:

Moved the code to the Form class, like so:

public function doSave(PropelPDO $con = null) {
  parent::doSave($con);

  if ($this->getObject()->getIsSiteOwner()) {
    $this->getObject()->setType(NULL);
    $this->getObject()->save();

    foreach($this->getObject()->getUserPartners() as $user_partner) {
      $user_partner->delete();
    }
  }

  return $this->getObject();
}

public function updateObject($values = null) {
  $obj = parent::updateObject($values);

  if ($obj->getIsSiteOwner()) {
    $obj->clearUserPartners();
  }

  return $this->object;
}

What this does is:

• When the boolean flag `is_site_owner` is up, it clear the `type` field and **saves** the object (ashamed I have not figured that out for so long).
• Removes all existing UserPartner many-to-many link objects.
• Clears newly associated (via the DoubleList) UserPartner relations.

Which is what I need. Thanks to all who participated.

Answer 1

Okey so now you have a many-to-many relation where in database terms is implemented into three tables (User, Parter and UserPartner). Same thing happens on Symfony and Propel, so you need to do something like this on the doSave method that should declare in UserForm:

public function doSave($con = null)
{
 parent::doSave($con); //First all that's good and nice from propel
 if ($this->getValue('please_errase_my_partners_field'))
 {
  foreach($this->getObject()->getUserPartners() as $user_partner_relation)
  {
   $user_partner_relation->delete();
  }
 }
 return $this->getObject();
}

Check the method name "getUserPartners" that should be declared on the BaseUser.class.php (lib/model/om/BaseUser.class.php)

Answer 2

If you are learning Symfony, I suggest you use Doctrine instead of Propel because, I think Doctrine is simplier and more "beautiful" than Propel.

For your problem, I think you are on the good way. If I were you, I will keep my function save() I will write an other function in my model User

public function clearUserPartners(){
    // You have to convert this query to Propel query (I'm sorry, but I don't know the right syntax)
    "DELETE FROM `USER_PARTNER` WHERE user_id = '$this->id'"
}

With this function, you don't must use a PHP foreach.

But I don't understand what is the attribute StringProperty ...

Answer 3

UserPartnerQuery::create()->filterByUser( $userObject )->delete();

or

UserPartnerQuery::create()->filterByUser( $partnerObject )->delete();

Had the same problem. This is a working solution.

Answer 4

The thing is that your second solution, ie. looping over the related objects and calling delete() on them should work. It's the documented way of doing things (see: http://www.symfony-project.org/book/1_0/08-Inside-the-Model-Layer#chapter_08_sub_saving_and_deleting_data ).

But instead of bombing the DB with delete queries, you could just as well delete them in one go, by adding a method to your Peer class that performs the deletion using a simple DB query.