Hi guys!
Which is the best approach to perform a check whether certain email is already in DB and thus detect attempts of users to register again with it.
I would rather use it in the same way as validation rules(I mean it should appear in the box with errors.
Additionally, I am planning to perform AJAX request, so that I inform the user just in time.
Penko
If you are using AR you can use the built in validation rule unique.
Like this:
<?php
public function rules()
{
return array(array('email', 'unique'));
}
?>
Where email is the name of the column for email in your database table.
Thanks, man. This was what I was looking for.
No worries
If I may add something, take care that when the user wants to update his/her email, the 'unique' validator is not appropriate and you could use a scenario based rule like for instance :
(example below would be for a name update …but the principle is tha same than for email)
array('name', 'ValidateUniqueName','attributes'=>'name', 'on' => 'update')
where ValidateUniqueName would be defined as a method:
public function ValidateUniqueName($attribute,$params)
{
$exist=User::model()->exists('name=:name and id!=:ID',
array(
':name' => $this->name,
':ID' => $this->id
)
);
if($exist)
{
$this->addError($attribute,'this name is already used');
}
}
I think this is the correct way to handle this situation and as I had to deal with it already, thought it may be useful to you.
ciao
Would you mind if I ask the difference between the two? I am not sure you allow two users (having the different id) having the same e-mail address.
oups ! you’re right … I was so focused on how to use scenario based rules that I didn’t noticed it was not useful here. 
Thank you Mocapapa for pointing it out
ciao
Pheeew, thanks for clearing this out guys. I was really confused about Raouls post and thought that I had missed something.
Hmm. Now i am confused 
. Didn’t use scenario based validation, but from my understanding i found Raoul’s tipp reasonable. As there are 2 scenarios:
User registers: email must be unique among all users in db.
User updates his information (but doesn't change his email): email must be unique among all users except himself.
Isn't that, what Raoul's post was about?
If the column being validated is not a PK, you can use the unique validator for both scenarios.
Yes, what you discuss is right. Actually I was getting errors when updating. However, I think the problem is related to the fact that I copied the create action code into the update action because I deleted it initially by thinking I am editing the create action. Now, I am having informatics class at school, so I can't check the code at home, so will check it and provide my feedback. Actually, it would be good if I am able to use action-based validators.