Linux, Apache, MySQL, PHP

I have a button in my form and on click of that button I am writing this code....
<pre>
OdbcCommand cmd ;
cmd = new OdbcCommand("abc", cn);
cmd.CommandType = CommandType.StoredProcedure;
cmd.ExecuteNonQuery();

$arr = array(5=>dog, 3=>cat, 6=>cow)

 public function isUsernameTaken($username)
    {
        $st = $this->getPdo()->prepare("select count(*) as cnt from ".
        $this->getDbUserTable()." where username=?");
        $row = $st->execute(array($username))->fetch();
        if($row['cnt']==0)
        {
            return false;
        }
        return true;
    }