CakePHP data validation on create and update - php

Question

I'm writing a customer management system using cakePHP (the first thing I've ever attempted to build using this framework), and I'm struggling to figure out how to validate certain fields when adding a new customer.
Each customer has an id that I need to be able to add manually, and a username that has to be unique but can be empty.
Here is what I want to happen:
When adding a new customer:
Check whether the id already exists and alert the user if it does (and not add the user)
Check whether the username already exists and alert the user if it does (and not add the user)
When updating a customer profile (the id cannot be modified at this point):
If the username has been modified, check whether it already exists and alert the user.
As it now stands, whenever I try adding a user with an existing id, cakePHP simply overwrites the existing id's info with the new info.
I've tried several validation options but nothing seems to work.
Here's the first:
public $validate = array(
'id' => array(
'idRule-1' => array(
'on' => 'create',
'rule' => 'uniqueID',
'message' => 'This Oracle ID already exists.',
'last' => false
),
'idRule-2' => array(
'rule' => 'numeric',
'message' => 'Oracle ID can only contain numbers.',
'last' => false
),
),
'username' => array(
'userRule-1' => array(
'on' => 'create',
'rule' => 'uniqueUser',
'message' => 'This username already exists',
'last' => false,
),
'userRule-2' => array(
'on' => 'update',
'rule' => 'oneUser',
'message' => 'The eBay username you are trying to modify already belongs to another seller',
'last' => false,
),
)
);
public function uniqueID() {
return ($this->find('count', array('conditions' =>array('Seller.id' => $this->data['Seller']['id']))) == 0);
}
public function uniqueUser() {
return ($this->find('count', array('conditions' =>array('Seller.username' => $this->data['Seller']['username']))) == 0);
}
public function oneUser() {
return ($this->find('count', array('conditions' =>array('Seller.username' => $this->data['Seller']['username']))) == 1);
}
and the second (only for the id):
public $validate = array(
'id' => array(
'unique' => array(
'rule' => 'isUnique',
'on' => 'create',
'message' => 'This Oracle ID already exists.',
)
)
);
And here are the add() and edit() methods of the controller:
public function add() {
if ($this->request->is('post')) {
$this->Seller->create();
if ($this->Seller->save($this->request->data)) {
$this->Session->setFlash(__('The seller has been saved'));
$this->redirect(array('action' => 'index'));
} else {
$this->Session->setFlash(__('The seller could not be saved. Please, try again.'));
}
}
$accountManagers = $this->Seller->AccountManager->find('list');
$primaries = $this->Seller->Primary->find('list');
$thirdParties = $this->Seller->ThirdParty->find('list');
$sites = $this->Seller->Site->find('list');
$meetings = $this->Seller->Meeting->find('list');
$this->set(compact('accountManagers', 'primaries', 'thirdParties', 'sites', 'meetings'));
}
/**
* edit method
*
* #throws NotFoundException
* #param string $id
* #return void
*/
public function edit($id = null) {
if (!$this->Seller->exists($id)) {
throw new NotFoundException(__('Invalid seller'));
}
if ($this->request->is('post') || $this->request->is('put')) {
$this->Seller->id = $id;
if ($this->Seller->save($this->request->data)) {
$this->Session->setFlash(__('The seller has been saved'));
$this->redirect(array('action' => 'index'));
} else {
$this->Session->setFlash(__('The seller could not be saved. Please, try again.'));
}
debug($this->Seller->validationErrors);
} else {
$options = array('conditions' => array('Seller.' . $this->Seller->primaryKey => $id));
$this->request->data = $this->Seller->find('first', $options);
}
$accountManagers = $this->Seller->AccountManager->find('list');
$primaries = $this->Seller->Primary->find('list');
$thirdParties = $this->Seller->ThirdParty->find('list');
$sites = $this->Seller->Site->find('list');
$meetings = $this->Seller->Meeting->find('list');
$this->set(compact('accountManagers', 'primaries', 'thirdParties', 'sites', 'meetings'));
}
Any and all tips will be greatly appreciated!

Answer 1

If the data you are trying to save contains an id, CakePHP assumes that you are updating an existing record. For a validation rule to be triggered on "create", the id should not be set. If the id is set, Cake will check for "update" rules.
So you should let your database affect ids for new records with an autoincrement, and then only manage validation when editing your existing users.