拒绝访问phpmyadmin中的数据库

创建check_login页面时出错

无法选择数据库：拒绝用户"@'localhost'访问数据库'clg'。

我已经在phpMyAdmin中创建了该表。我该如何解决这个问题？

这是完整的代码：

$host="localhost"; // Host name 
$username=""; // Mysql username 
$password=""; // Mysql password 
$db_name="clg"; // Database name 
$tbl_name="hr"; // Table name 
// Connect to server and select databse. 
mysql_connect("$host", "$username", "$password")or die('cannot connect:' . mysql_error()); 
mysql_select_db("$db_name")or die('cannot select DB:' . mysql_error());
//Define $username and $password 
$userid = $_POST['userid']; 
$password=$_POST['password']; 
// To protect MySQL injection (more detail about MySQL injection) 
$userid = stripslashes($userid); 
$password = stripslashes($password); 
$userid = mysql_real_escape_string($userid); 
$password = mysql_real_escape_string($password); 
$sql="SELECT * FROM $tbl_name WHERE userid='$userid' and password='$password'";
$result=mysql_query($sql);
// Mysql_num_row is counting table row 
$count=mysql_num_rows($result); 
// If result matched $myusername and $mypassword, table row must be 1 row 
if($count==1){ 
   // Register $myusername, $mypassword and redirect to file "login_success.php" 
   session_register("userid"); 
   session_register("password"); 
   header("location:login_success.php"); 
} else { 
   echo "Wrong Username or Password"; 
}