数据库错误MySQL / CodeIgniter插入新值时的PHP

When I am trying to insert a new value in a MySQL database, I have the following error:

Error Number: 1048

Column 'email' cannot be null

INSERT INTO emails(email)VALUES(NULL)

Filename: models/Model_email.php

Line Number: 7

I had not this error when I was running the website on the local server, the error appeared on production. I code in PHP with the framework CodeIgniter.

The code is pretty simple though:

Controler.php

public function addemail(){

    ini_set('display_errors','off');
    $this->load->model("Model_email","", true);
    $this->Model_email->addemail($_POST["email"]); 

}

Model_email.php

public function addemail($email){
    $sql = "INSERT INTO emails(email)VALUES(?)";
    $data = array($email);
    $this->db->query($sql,$data);
    return $this->db->insert_id();
}

HTML form

<form method="post" action="<?=site_url("/Controler/addemail")?>">
<input type="text" name="email">
<input type="submit">
</form>

When I add a var_dump($email) in the function in Model_email.php or a var_dump($_POST["email"]) in Controler.php, both page shows a NULL. However the method post in the form seems to be right.

Try this:

public function addemail(){
    //ini_set('display_errors','off');
    $this->load->model('Model_email');
    $this->Model_email->addemail($this->input->post('email'));
}

try:

var_dump($this->input->post(NULL, TRUE));

to view what is submitted, by then you will see what is submitted by POST.

Try this

public function addemail(){
    //ini_set('display_errors','off');
    if(isset($_POST["email"]) && $_POST["email"] && !empty($_POST["email"])){
         $this->load->model("Model_email","", true);
         $this->Model_email->addemail($_POST["email"]); 
    }
}

Use this one :

$data = array( 'email' => $email

);

$this->db->insert('tablename', $data);

// Produces: INSERT INTO mytable (title, name, date) VALUES ('My title', 'My name', 'My date')