PHP错误:未选择数据库(Hostgator.com）

我在使用PHP将数据插入MySQL时遇到问题。当我在我的Hostgator主机上运行此代码时，我会得到这样的错误：

未选择数据库

这是我的代码：

$dbh= mysql_connect("localhost", $username, $password);
   // or die ('I cannot connect to the database because: ' . mysql_error());
   if(!$dbh)
   {
     die('Could not connect: ' . mysql_error());
   }
   mysql_select_db("contafe_tipster", $dbh);
   //$conn = mysqli_connect($servername, $username, $password, $dbname);
   //Check connection
   /*
   if (!$conn) {
       // Connection failed return 0
       //die("Connection failed " . mysqli_connect_error());
       echo "1";
   }
   */
   //Posted parameters
   $pName = $_POST['name'];
   $pCountry = $_POST['country'];
   $pCity = $_POST['city'];
   $pLocationX = $_POST['locationX'];
   $pLocationY = $_POST['locationY'];
   $pDescription = $_POST['description'];
   $pMobileNumber = $_POST['mobile'];
   $pOtherNumber = $_POST['phone'];
   $pOpens = $_POST['opens'];
   $pCloses = $_POST['closes'];
   $add_DB = "INSERT INTO Places (Id, Name, Country, City, LocationX, LocationY,        Description, Mobile, Phone, Opens, Closes) 
    VALUES(NULL, '$pName', '$pCountry', '$pCity', '$pLocationX', '$pLocationY',   '$pDescription', '$pMobileNumber', '$pOtherNumber', '$pOpens', '$pCloses')";
   if (mysql_query($add_DB, $dbh)) {
       //if success return 1
       echo "0";
   } 
   else {
       //if error return -1
       //echo "2";
         die('Error: ' . mysql_error());
   }
   mysql_close($dbh);