使用开关和某些函数的意外Inifite循环

基本上我有一段代码，它有一个switch语句和一些函数。它使用浏览器"?step=X"给出的参数进入switch语句，然后选择适当的函数。

我的问题是，即使在我指定转到下一个switch语句的每个函数结束时，它也从未执行过，而且不知何故，它变成了我在浏览器中用"step=x"选择的函数的无限循环。。。

为什么被困在1个函数中而不迭代它们？（该步骤的代码在脚本末尾突出显示）

我在浏览器中获得任何选定函数的输出。因此它进入开关和所选功能。。。但后来它变成了一个无限循环，因为在broswer中我得到了300个相同的echo语句。它永远无法遍历它们或退出所选函数。

<?php 
//DB Config File
$dbFile = 'dbconfig.php';
$username = $_GET['username'];
$password = $_GET['password'];
$server = $_GET['server'];
$dbname = $_GET['dbname'];
$step = $_GET["step"];


function createfile ($dbFile) {
        //Creates File and populates it.
        $fOpen = fopen($dbFile, 'w');
global $username, $password, $server, $dbname;
            $fString .= "<?php'n";
            $fString .= "// Database Constants'n";
            $fString .= "'$DB_SERVER =" . "'"" . $server . "'";'n";
            $fString .= "'$DB_USER =" . "'"" . $username . "'";'n";
            $fString .= "'$DB_PASS =" . "'"" . $password . "'";'n";
            $fString .= "'$DB_NAME =". "'"" . $dbname . "'";'n";
            $fString .= "?>";
        fwrite($fOpen, $fString);
        fclose($fOpen);
return true;
}


try {
$db = new PDO ('mysql:host=' .$server.';dbname='.$dbname,$username,$password);
if ($db) { //if succesful at connecting to the DB
if (file_exists($dbFile)){
    if (is_readable($dbFile) && is_writable($dbFile)){ 
        //Creates File, populates it and redirects the user
    if (createfile($dbFile)) { 
    echo "nelxt";
    stepFunction($step);
    exit ();
            }

        } else { 
        echo "The file {$dbFile} cannot be accessed. Please configure the file manualy or grant Write and Read permission.";  }
    } else {
        //Creates File, populates it and redirects the user
    if (createfile($dbFile)) {
    echo "next";
        stepFunction($step);
    exit ();
            }
        }

}
} catch (PDOException $e) { //Catchs error if can't connect to the db.
    echo  'Connection failed: ' . $e->getMessage();
}
// Prepare SQL Statements
$IDB = $db->prepare( 
 "CREATE TABLE pages (
  id int(11) NOT NULL auto_increment,
 subject_id int(11) NOT NULL,
  menu_name varchar(30) NOT NULL,
  position int(3) NOT NULL,
  visible tinyint(1) NOT NULL,
  content text NOT NULL,
  PRIMARY KEY  (id)
)ENGINE=MyISAM AUTO_INCREMENT=7 DEFAULT CHARSET=utf8");
$IDB2 = $db->prepare("
CREATE TABLE subjects (
  id int(11) NOT NULL auto_increment,
  menu_name varchar(30) NOT NULL,
  position int(3) NOT NULL,
  visible tinyint(1) NOT NULL,
  PRIMARY KEY  (id)
)ENGINE=MyISAM AUTO_INCREMENT=6 DEFAULT CHARSET=utf8");
$IDB3 = $db->prepare("
CREATE TABLE users (
  id int(11) NOT NULL auto_increment,
  username varchar(50) NOT NULL,
  hashed_password varchar(40) NOT NULL,
  PRIMARY KEY  (id)
)ENGINE=MyISAM AUTO_INCREMENT=2 DEFAULT CHARSET=utf8");
//Set Option to True or False
if (empty ($_GET['fot']) ) { 
    $fOT = false; 
    } else { $fOT = true;
        }
///////////////////////////////
// PROBLEMATIC STEP BEGINS HERE 
///////////////////////////////
function createTablePages (){
    global $db,$IDB;
                echo "0 <br>";
                stepFunction (1);
}
function createTableSubjects ($fOT){
    global $db,$IDB2;

                echo "1 <br>";
                stepFunction (2);
}
function createTableUsers ($fOT){
    global $db,$IDB3;
    echo "3 <br>";
}
function stepFunction ($step,$fOT){
global $db,$IDB1,$IDB2,$step,$fOT;

switch ($step) {
    case 0: echo "hola";
            createTablePages ($fOT);
            break;
    case 1: echo "hola2";
            createTableSubjects($fOT);
            break;
    case 2: createTableUsers ($fOT);
            break;
    }

}
?>