如何使用codeigniter检查用户名是否已存在

Question

I want to create a login form validation. In that I need to check whether the username and email already exist. If exist display error

I tried this tutorial for CRUD

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

    class Insert extends CI_Controller {

        // For data insertion
        public function index(){

            //Setting validation rules
            $this->form_validation->set_rules('firstname','First Name','required|alpha');
            $this->form_validation->set_rules('lastname','Last Name','required|alpha');
            $this->form_validation->set_rules('emailid','Email id','required|valid_email');
            $this->form_validation->set_rules('contactno','Contact Number','required|numeric|exact_length[10]');
            $this->form_validation->set_rules('address','Address','required');

            if($this->form_validation->run()){
                $fname=$this->input->post('firstname');
                $lname=$this->input->post('lastname');
                $email=$this->input->post('emailid');
                $cntno=$this->input->post('contactno');
                $adrss=$this->input->post('address');
                //loading model
                $this->load->model('Insert_Model');
                $this->Insert_Model->insertdata($fname,$lname,$email,$cntno,$adrss);
                $this->load->view('insert');
            } else {
                $this->load->view('insert');
            }
        }
    }

Answer 1

What you want to do is modify your rules for the form validation as below :

Just add is_unique[tablename.fieldname] rules to the form validation. for Example:

$this->form_validation->set_rules('emailid','Email id','required|valid_email|is_unique[yourTableName.yourEmailFieldName]');

BTW: You could also use trim in the rules for your email

Answer 2

    $this->db->where('emailid', $email); // OTHER CONDITIONS IF ANY
    $this->db->from('tblusers'); //TABLE NAME
    echo $this->db->count_all_results();
if($this->db->count_all_results() > 0)
{
echo "Duplicate Record";
}
else
{
echo  "New record";
}

Hope this will help you out.. just understand the logic

Answer 3

Also u can assign your custom validation method

$this->form_validation->set_rules('emailid','Email id','required|valid_email|callback_username_check');

    public function username_check($str)
    {
           //your db query to check email exists and return true or false
    }