check if a value already exists in database

How to check if a value already exists in database using built in form validation methods ?

Thanks in advance 

See the documentation for making your own callback methods:

https://www.codeigniter.com/userguide3/l...on-methods

It is within one of these callback methods that you would simply query your database for an existing value.

Brian's Web Design - Temecula, CA
Community Auth For CodeIgniter 3
Community Auth

There is also a built-in validation rule for that: is_unique.
https://www.codeigniter.com/user_guide/l...-reference

Note that under CI version 2, if you chained validation rules, you could not put spaces between them.

PHP Code:

// works
$this->form_validation->set_rules('email', 'Email', 'required|is_unique[users.email]');
// doesn't work
$this->form_validation->set_rules('email', 'Email', 'required | is_unique[users.email]'); 


Usually, white space doesn't matter in code, but in this case, it does. I don't know if that's still the case in version 3, but just so you know...

Hey, don't work without a PHP debugger. Several free IDEs have this features built in. Two are NetBeans and CodeLobster. Without a debugger, it's like you're driving with a blindfold on -- you are going to crash!

There is also a built-in validation rule for that: is_unique.
https://www.codeigniter.com/user_guide/l...-reference

Note that under CI version 2, if you chained validation rules, you could not put spaces between them.

PHP Code:

// works
$this->form_validation->set_rules('email', 'Email', 'required|is_unique[users.email]');
// doesn't work
$this->form_validation->set_rules('email', 'Email', 'required | is_unique[users.email]'); 


Usually, white space doesn't matter in code, but in this case, it does. I don't know if that's still the case in version 3, but just so you know...

This is the easier way to do it, but if you want to have a customized error message then you need to use a callback, or do something creative with str_replace.

Brian's Web Design - Temecula, CA
Community Auth For CodeIgniter 3
Community Auth

Thanks for help.

I need the reverse of is_unique ie, the rule should return true if an entry exists in the database.

Then you need to add a callback function:

PHP Code:

<?php

class Form extends CI_Controller {

        public function index()
        {
                $this->load->helper(array('form', 'url'));

                $this->load->library('form_validation');

                $this->form_validation->set_rules('username', 'Username', 'required|callback_exists_in_database');                
                $this->form_validation->set_rules('password', 'Password', 'required|min_length[8]');

                if ($this->form_validation->run() == FALSE)
                {
                        $this->load->view('myform');
                }
                else
                {
                        $this->load->view('formsuccess');
                }
        }

        public function exists_in_database($username)
        {

                $query = $this->db->get_where('my_users', array('username' => $username)); 

                if ($query->num_rows() == 0 )
                {
                        $this->form_validation->set_message('exists_in_database', 'Please enter an existing username');
                        return FALSE;
                }
                else
                {
                        return TRUE;
                }
        }

} 


I know it can be done with callbacks.
Just looking for in-built validation methods.

Thanks

I know it can be done with callbacks.
Just looking for in-built validation methods.

Thanks

There are none, but if you are looking to re-use such a callback many times, consider adding it to a MY_Form_validation.php file.

Brian's Web Design - Temecula, CA
Community Auth For CodeIgniter 3
Community Auth

How to check if a value already exists in database using built in form validation methods ?

Thanks in advance 

yeah, i am late for a reply, but i have the simplest way to check if a value already exists, just extend form validation class by MY_Form_validation like this:

PHP Code:

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class MY_Form_validation extends CI_Form_validation {

    public function is_exists($str, $field)
    {
        return $this->is_unique($str, $field) === FALSE;
    }

} 


now, create form_validation_lang.php file in your language directory and:

PHP Code:

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

$lang['form_validation_is_exists'] = 'The {field} field is already exists.'; 


that's all, now u can use in this way

PHP Code:

$rules = array(
    array(
        'field' => 'email',
        'label' => 'lang:email',
        'rules' => 'required|is_exists[users.email]'
    )
);