cakephp SQL error at $this->User->saveField() - php

Question

When I try to update a user, let's say his account balance
$this->User->id = $validUserId;
$this->User->saveField('balance', 100);
I get this error
SQL Error: 1054: Unknown column 'User.group_id' in 'field list'
with this automatically generated query druring the save process
SELECT `User`.`group_id` FROM `users` AS `User` WHERE `User`.`id` = *validUserId* LIMIT 1
The user belongsTo a UserGroup and therefore the user has user_group_id attribute, is there any way to tell cake, that the attribute is related to a UserGroup?
Thanks in advance,
EL

Answer 1

Maybe, if you are just saving a field, you don't need to do validations. In that case just do
$this->User->saveField('balance', 100, false);
http://api.cakephp.org/class/model#method-ModelsaveField
Or if there is a callback like beforeSave or something, I think you can do something like:
$this->save($data, array('validate'=>false, 'callbacks'=>false));
Hope this helps

Answer 2

Most certainly, the models should look like this:
class UserGroup extends AppModel {
var $belongsTo = array(
'UserGroup' => array(
'className' => 'UserGroup',
'foreignKey' => 'user_group_id'
)
);
}
class User extends AppModel {
var $hasMany = array(
'User' => array(
'className' => 'User',
'foreignKey' => 'user_group_id'
)
);
}
Read about associating CakePHP models in the book