Having code problem inserting into a query

[Agent12]

Having trouble updating or inserting into a field in the db.
Other actions in other pages seems to work correctly.
What is my problem here?

10x helpers

echo "<form method=\"post\" action=\"index.php\">"
        ."<b>Text here:</b><br><textarea name=\"content\" value=\"$content\" cols=\"50\" rows=\"200\"></textarea>"
	."<input type=\"hidden\" name=\"case\" value=\"update\">"
	."<center><input type='submit' value='send'></center>"
		."</form>";
switch($case) {

  case "update":
	update_news($content);
}

function update_news($content) {
    global $db


$db->sql_query("UPDATE new_content SET stext = '$content' WHERE t_id  = '1' ");
  }