How to Use is_unique in Form Validation on UPDATE in CodeIgniter 3

CodeIgniter provides a comprehensive form validation and data prepping class that helps developers make form submission easier.

Among the rule, is_unique is a useful one to check whether a field exists in the database.

is_unique

Yes

Returns FALSE if the form element is not unique to the table and field name in the parameter. Note: This rule requires Query Builder to be enabled in order to work.

is_unique[table.field]

It works perfectly in situations when you need to create a new record. However, it doesn’t when you need to update an old record. This rule checks the data against its own record set so it always returns a duplication.

Add the rule when the data is different

This method is simple. We compare the original data with the newly submitted one. If they are different, we add is_unique rule, otherwise, don’t add the rule.

if(trim($user->phone) != trim($this->input->post('phone'))){
	$this->form_validation->set_rules('phone', 'Phone', 'required|is_unique[user.phone]');
} else {
	$this->form_validation->set_rules('phone', 'Phone', 'required');
}

Create your own validation methods

CodeIgniter 3 validation system supports callbacks to your own validation methods. We can create a new callback called callback_phone_check to check for the phone number.

$this->form_validation->set_rules('phone', 'Phone', 'callback_phone_check');

public function phone_check($phone){
	//query database here then compare data
	if ($duplicated){
            $this->form_validation->set_message('phone_check', 'The phone is duplicated');
            return FALSE;
	} else {
            return TRUE;
	}
}