how to check if username already exists in codeign

问题:

I am working on a site in codeigniter.I am not so expert using framework.Here I have to check if email already exists in database.I have coded the required functionality but I am getting an error when submit the form. In controller i have made the following rule.

My code is:

$this->form_validation->set_rules(
    'email', 'Email', 'trim|required|valid_email|is_unique|callback_isEmailExist'
);
public function isEmailExist($email) {
    $this->load->library('form_validation');
    $this->load->model('user');
    $is_exist = $this->user->isEmailExist($email);

    if ($is_exist) {
        $this->form_validation->set_message(
            'isEmailExist', 'Email address is already exist.'
        );    
        return false;
    } else {
        return true;
    }
}

in model user the function is :

function isEmailExist($email) {
    $this->db->select('id');
    $this->db->where('email', $email);
    $query = $this->db->get('users');

    if ($query->num_rows() > 0) {
        return true;
    } else {
        return false;
    }
}

When I submit the form, I am getting the following errors.

A PHP Error was encountered

Severity: Notice

Message: Undefined offset: 1

Filename: libraries/Form_validation.php

Line Number: 953

A Database Error Occurred

Error Number: 1064

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHERE ` = '[e-mail]' LIMIT 1' at line 2

SELECT * WHERE ` = '[e-mail]' LIMIT 1

Filename: C:\xampp\htdocs\aunction\system\database\DB_driver.php

Line Number: 330 Anyone help me please. Thanks in advance.

回答1:

Your problem is in the set_rules line. Here you use both is_unique and a callback function. You have to use anyone of that. If you use a call_back function to check duplicate data; doesn't need to use is_unique. For this wrong you get that error Just remove the is_unique from there.

$this->form_validation->set_rules('email','Email','trim|required|valid_email|callback_isEmailExist'); // removed is_unique

Try this out and let me know.

回答2:

$this->form_validation->set_rules('username', 'userName', 'required|callback_exists_username');


#uniqueness of username
    function exists_username($str)
    {
        $record_id = $this->input->post('record_id');
        $condition = array('user_id !='=>$record_id,'username'=>$str);
        $value =GetAllRecord('user_master',$condition,$is_single=true);
        if (count($value) == 0)
        {
            return TRUE;
        }
        else
        {
            $this->form_validation->set_message('exists_username', 'username already exists!');
            return FALSE;
        }
    }

回答3:

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

 array('field' => 'email', 'label' => 'Email', 'rules' => 'trim|required|valid_email|is_unique[users.email]'));

回答4:

Your Model is like

$this->db->select('id');
$this->db->where('email', $email);

please tell the mysql from which table you want to get the record.

$this->db->from('tablename');

it would be like

$this->db->select('id');
$this->db->from('tablename');
$this->db->where('email', $email);

回答5:

You have an error in the mysql query:-

SELECT * WHERE ` = '[e-mail]' LIMIT 1

Your code has not specified which table to query from. So use following:-

$this->db->select('id');
$this->db->from('tablename');
$this->db->where('email', $email);

Hope this helps.

回答6:

no need to a make a special function, this is enough

$this->form_validation->set_rules(
    'email', 'Email', 'trim|required|valid_email|is_unique'
);

回答7:

Use is_unique[table.field] add table name and field.

$this->form_validation->set_rules(
    'email', 'Email', 'trim|required|valid_email|is_unique[table.field]|callback_isEmailExist'
);

回答8:

you can check if a field is unique or not by using form_validator function is_unique[table_name.field_name]