How do I load associated models and save related data in CakePHP? - cakephp

Question

I am setting up a user/group system that allows users to send requests to join a group.
I can't seem to load the associated model and add a row. It's really really really difficult to resist the urge to just use $this->query() and be done with it... but I'm trying to learn the Cake conventions and do things the right way.
In my group model's function for handling group join requests:
$this->loadModel('GroupRequest');
$this->data = array('GroupRequest' =>
array('user_id' => $uid, 'group_id' => $gid));
if($this->GroupRequest->save($this->data)){ echo 'save success'; }
else { echo 'save fail'; }
Here are the errors I get when I run this:
Warning (512): SQL Error: 1064: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'loadModel' at line 1 [CORE/cake/libs/model/datasources/dbo_source.php, line 684]
Query: loadModel
Notice (8): Undefined property: Group::$GroupRequest [APP/models/group.php, line 124]
Fatal error: Call to a member function save() on a non-object in /home/wxworksmat/sspot3/app/models/group.php on line 124
I also tried using App::import:
App::import('Model','GroupRequest');
I don't get any SQL errors importing the Model this way, but it still doesn't work. I get the following error on the save() or create() call:
Fatal error: Call to a member function save() on a non-object in /home/wxworksmat/sspot3/app/models/group.php on line 124

Answer 1

You are confusing controller and model methods
$this->loadModel()
is a controller method and can only be used there.
You should always use
$this->ModelName = ClassRegistry::init('ModelName');
everywhere else

Answer 2

I might be wrong, and please excuse me if I'm wrong, but it looks like you don't understand the concept of the framework very well. It is difficult to answer your question without giving you a complete tutorial.
This said, everything relies on model associations. If it's done correctly, things are getting easy. You should read:
Associations: Linking Models Together
Once you have your models correctly linked, you will be able to save the primary model, as well as the related model, very easily.
Saving Related Model Data (hasOne, hasMany, belongsTo)

Answer 3

As I understand, you are trying to do this from inside a model?
class GroupRequest extends AppModel {
public function associate($user, $group) {
$data["GroupRequest"] = array("user_id" => $user, "group_id" => $group);
$this->save($data);
}
}
Then in your Controller (assuming group_requests_controller)
$this->GroupRequest->associate($user, $group);
If you're calling this from another controller you would loadModel first
$this->loadModel("GroupRequests");
$this->GroupRequest->associate($user, $group);
However, if you're doing all of this from within GroupRequests controller you should be able to save directly, without making a separate method for it
public function add() {
$this->GroupRequest->create();
$this->GroupRequest->save($this->data); #for < 2.0
}
Your view should be something like
<?php
echo $this->Form->create("GroupRequest");
echo $this->Form->input("user_id");
echo $this->Form->input("group_id");
echo $this->Form->end("Submit");
?>

Answer 4

The problem I had was that I didn't have the correct model association declarations at the top of my model.
Now I have:
group.php
var $hasMany = 'GroupRequest';
group_request.php
var $belongsTo = array(
'User' => array(
'className' => 'User',
'foreignKey' => 'user_id',
'conditions' => '',
'fields' => '',
'order' => ''
),
'Group' => array(
'className' => 'Group',
'foreignKey' => 'group_id',
'conditions' => '',
'fields' => '',
'order' => ''
)
);
public function new_request($user, $group) {
$data["GroupRequest"] = array("user_id" => $user, "group_id" => $group, 'status' => 'pending');
if($this->save($data)){ return true;} else {return false;}
}
Now because everything is set up CORRECTLY... I can do this in my group.php model:
$this->GroupRequest->new_request($uid,$gid)
As an added bonus, because the assocations are populating properly, when I do $this->find in my group or user model, now all the related GroupRequest entries show up. Bonus data FTW.