Why I can't access the newly created table in wordpress this way?

I've already created the table successfully:

function jal_install () {
  global $wpdb;
  global $jal_db_version;
  $table_name = $wpdb->prefix . "liveshoutbox";
  if($wpdb->get_var("show tables like '$table_name'") != $table_name) {
      $sql = "CREATE TABLE " . $table_name . " (

id mediumint(9) NOT NULL AUTO_INCREMENT, time bigint(11) DEFAULT '0' NOT NULL, name ti开发者_开发技巧nytext NOT NULL, text text NOT NULL, url VARCHAR(55) NOT NULL, UNIQUE KEY id (id) );";

    require_once(ABSPATH . 'wp-admin/includes/upgrade.php');
     dbDelta($sql);
     $welcome_name = "Mr. Wordpress";
     $welcome_text = "Congratulations, you just completed the installation!";
     $insert = "INSERT INTO " . $table_name .
           " (time, name, text) " .
           "VALUES ('" . time() . "','" . $wpdb->escape($welcome_name) . "','" . $wpdb->escape($welcome_text) . "')";
     $results = $wpdb->query( $insert );
  }
}

jal_install ();

But when I try to refer to this table as how WP refers to its internal tables like $wpdb->posts:

var_dump($wpdb->liveshoutbox);

The output is :

null

Why?

I know it's been a while since this thread appeared, but thought I'd share how I solved it. The answer it seems is to refer to the table name in full including the prefix without $wpdb->. Not sure it it works for var_dump, but it did for getting rows and results

There is no support for

$wpdb->liveshoutbox

and only internal table have direct access to: (eg)

$wpdb->posts

For that, your only option is:

$wpdb->prefix . "liveshoutbox"