Why do I get error : Undefined variable?

I created an input script. I write name and script post name into database. But I have error - ErrorException [ Notice ]: Undefined variable: result .

There is my controller:

class Controller_About extends Controller_Template{
    public function action_index()
    {
        if(!empty($_POST['name'])){
            $name = Model::factory('index')->insert_names($_POST['name']);;
            $result= $name;
        }
        $this->template->site_name = Kohana::$config->load('common')->get('site_name');
        $this->template->site_description = Kohana::$config->load('common')->get('site_description');
        $this->template->page_title = 'About';
        $this->template->content = View::factory('about/about')->set('result', $result);
        $this->template->styles[] = 'index/index';
    }
}

There is my view:

<form action="">
    <input type="text" name="name" />
</form>

And the is my model:

Class Model_Index Extends Model {

    public static function insert_names($name){
        $query = DB::query(DATABASE::INSERT, 'INSERT INTO names (name) VALUES (:name)')->parameters(array(':name' => $name));
    }
}

Where is the problem?

Edit #1

I edited the controller:

class Controller_About extends Controller_Template{
    public function action_index()
    {$result = '';
        if(!empty($_POST['name'])){
            $name = Model::factory('index')->insert_names($_POST['name']);;
            $result= $name;
        }
        $this->template->site_name = Kohana::$config->load('common')->get('site_name');
        $this->template->site_description = Kohana::$config->load('common')->get('site_description');
        $this->template->page_title = 'About';
        $this->template->content = View::factory('about/about')->set('result', $result);
        $this->template->styles[] = 'index/index';
    }
}

But this not working, because when I input name, they not puts i开发者_如何学Pythonnto database.

Possibly because an empty value was passed to name and the variable doesn't get initialized unless its non-empty. But it gets used in the following line, outside the if

$this->template->content = View::factory('about/about')->set('result', $result);

Initialize $result outside the if():

$result = "";
if(!empty($_POST['name'])){
    $name = Model::factory('index')->insert_names($_POST['name']);;
    $result= $name;
}

Or move the entire block that follows the if(){} inside it.

public function action_index()
{
    if(!empty($_POST['name'])){
      $name = Model::factory('index')->insert_names($_POST['name']);;
      $result= $name;

      // move this inside the if()
      $this->template->site_name = Kohana::$config->load('common')->get('site_name');
      $this->template->site_description = Kohana::$config->load('common')->get('site_description');
      $this->template->page_title = 'About';
      $this->template->content = View::factory('about/about')->set('result', $result);
      $this->template->styles[] = 'index/index';
   }
}

Add the method attribute to your form:

<form action="" method="post">

Change:

if(!empty($_POST['name'])){

To:

$result = '';
if(!empty($_POST['name'])){

And ensure that:

$this->template->content = View::factory('about/about')->set('result', $result);

will work when $result is empty.

You have no POST variable called name, therefore $result never gets set.

You forgot to actually run your query:

public static function insert_names($name)
{
    $query = DB::query(DATABASE::INSERT, 'INSERT INTO names (name) VALUES (:name)')->parameters(array(':name' => $name))->execute();
}

However it'd be a better approach to use Kohana's query builder:

public static function insert_names($name)
{
    $query = DB::insert('names', array('name'))->values(array($name))->execute();
}

or, considering from your code I can judge you're a beginner, you can use ORM and simplify it even further by doing this directly in controller:

if(!empty($_POST['name']))
{
    $result = ORM::Factory('index')->set(array('name' => $_POST['name']))->save();
}

However the problem will still exist because your insert_names method doesn't return anything so you'll be setting your template's result variable as FALSE.

I believe what you would like to do looks like this:

public static function insert_names($name)
{
    if(DB::insert('names', array('name'))->values(array($name))->execute())
    {
        return $name;
    }
}

(with ORM it wouldn't be necessary to create this method in the first place)

I see another error in your controller though - I guess you're not used to E_NOTICE errors. Rather than setting $result as empty string, it'd be better to simply refactor your code a little bit:

if(!empty($_POST['name']))
{
    $this->template->content = View::factory('about/about');

    if($name = Model::factory('index')->insert_names($_POST['name']))
    {
        $this->template->content->set('result', $_POST['name']);
    }
    else
    {
        // some kind of error message
    }
}

It might be a good idea to group all these variables from template into one, nice family:

class Controller_About extends Controller_Template{
    public function action_index()
    {
        $config = Kohana::$config->load('common');
        $this->template->set(array(
            'site_name' => $config->get('site_name'),
            'site_description' => $config->get('site_description'),
            'page_title' => 'About',
            'styles' => 'index/index'
        ));

        $this->template->content = View::factory('about/about');

        if($name = Model::factory('index')->insert_names($_POST['name']))
        {
            $this->template->content->set('result', $_POST['name']);
        }
        else
        {
            // some kind of error message
        }
    }
}

There. Isn't that A LOT cleaner? :)

It could still use Validation though, but that doesn't cover your original question so I'll just leave it that way.