Ask the great God to tell me what's wrong with the code. Why the session variable does not take effect

Ask the great God what's wrong with this code, why does the session variable not take effect?

 

 if (!function_exists ("getsqlvaluestring")) {
function getsqlvaluestring ($theValue, $theType, $theDefinedValue = "", $theNotDefinedValue = "")
{
$theValue = GET_MAGIC_QUOTES_GPC ()? Stripslashes ($theValue): $theValue;

$theValue = function_exists ("mysql_real_escape_string")? Mysql_real_escape_string ($theValue): mysql_escape_string ($theValue);

Switch ($theType) {
Case "Text":
$theValue = ($theValue! = "")? "". $theValue. "'": "NULL";
Break
Case "Long":
Case "int":
$theValue = ($theValue! = "")? Intval ($theValue): "NULL";
Break
Case "Double":
$theValue = ($theValue! = "")? "". Doubleval ($theValue). "'": "NULL";
Break
Case "Date":
$theValue = ($theValue! = "")? "". $theValue. "'": "NULL";
Break
Case "defined":
$theValue = ($theValue! = "")? $theDefinedValue: $theNotDefinedValue;
Break
}
return $theValue;
}
}

mysql_select_db ($database _yiwuyiwu, $yiwuyiwu);
$query _recordset1 = "SELECT * from ' user '";
$Recordset 1 = mysql_query ($query _recordset1, $yiwuyiwu) or Die (Mysql_error ());
$row _recordset1 = Mysql_fetch_assoc ($Recordset 1);
$totalRows _recordset1 = mysql_num_rows ($Recordset 1);
?>

 Validate request to login to this site.
if (!isset ($_session)) {
Session_Start ();
}
The session variable starts.
$loginFormAction = $_server[' php_self ');
if (Isset ($_get[' AccessCheck ')) {
$_session[' prevurl '] = $_get[' AccessCheck '];
}

if (Isset ($_post[' Username ')) {
$loginUsername =$_post[' Username '];
$password = (MD5 ($_post[' password '));
$MM _flduserauthorization = "Enable";
$MM _redirectloginsuccess = "index.php";
$MM _redirectloginfailed = "zhuce.php";
$MM _redirecttoreferrer = false;
Enter your account number and password to determine the steering page.
mysql_select_db ($database _yiwuyiwu, $yiwuyiwu);
  
$LoginRS __query=sprintf ("Select u_id U_name, pass, enable from ' user ' WHERE u_name=%s and pass=%s",
The Enable symbol is this "·"
Getsqlvaluestring ($loginUsername, "text"), getsqlvaluestring ($password, "text"));
   
$LoginRS = mysql_query ($LoginRS __query, $yiwuyiwu) or Die (Mysql_error ());
$row _loginrs = Mysql_fetch_assoc ($LoginRS);
$loginFoundUser = mysql_num_rows ($LoginRS);
  
  
if ($loginFoundUser) {
    
$loginStrGroup = mysql_result ($LoginRS, 0, ' Enable ');
    
Declaring three session variables and assigning a value
$_session[' mm_username '] = $loginUsername;
$_session[' mm_usergroup '] = $loginStrGroup;
$_session[' u_id ']= $row _loginrs (' u_id ');

if (Isset ($_session[' Prevurl ')) && false) {
$MM _redirectloginsuccess = $_session[' Prevurl ');
}
Header ("Location:".) $MM _redirectloginsuccess);
}
else {
Header ("Location:".) $MM _redirectloginfailed);
}
}
?>




 
  
 
<title></title>



  
Login System

  
 
  
 


  
  
 
  
 
  
 
  
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 user login