Random "new" error!

zachatk · 11-22-2010, 08:49 PM

Warning: mysql_numrows(): supplied argument is not a valid MySQL result resource in /home/a2986016/public_html/database.php on line 218

I'm getting that error and it's driving me nuts! It's been happening recently. Here's what makes it weird. I'll go onto my site and I should be logged in. However I get that error and it says I'm not logged in. If I press refresh a few times, the error will go away and I'll be logged in!

Sometimes I'll be going through my site when I suddenly log out and get that error. However I'm not truly logged out because if I refresh it the error won't be there and I'll refresh and I'll be signed in.

EDIT:

Warning: mysql_numrows(): supplied argument is not a valid MySQL result resource in /home/a2986016/public_html/database.php on line 207

Is another error I get randomly.

Here is database.php:

PHP Code:


			
<?
/**
 * Database.php
 * 
 * The Database class is meant to simplify the task of accessing
 * information from the website's database.
 *
 * Written by: Jpmaster77 a.k.a. The Grandmaster of C++ (GMC)
 * Last Updated: August 17, 2004
 */
include("constants.php");
      
class MySQLDB
{
   var $connection;         //The MySQL database connection
   var $num_active_users;   //Number of active users viewing site
   var $num_active_guests;  //Number of active guests viewing site
   var $num_members;        //Number of signed-up users
   /* Note: call getNumMembers() to access $num_members! */

   /* Class constructor */
   function MySQLDB(){
      /* Make connection to database */
      $this->connection = mysql_connect(DB_SERVER, DB_USER, DB_PASS) or die(mysql_error());
      mysql_select_db(DB_NAME, $this->connection) or die(mysql_error());
      
      /**
       * Only query database to find out number of members
       * when getNumMembers() is called for the first time,
       * until then, default value set.
       */
      $this->num_members = -1;
      
      if(TRACK_VISITORS){
         /* Calculate number of users at site */
         $this->calcNumActiveUsers();
      
         /* Calculate number of guests at site */
         $this->calcNumActiveGuests();
      }
   }

   /**
    * confirmUserPass - Checks whether or not the given
    * username is in the database, if so it checks if the
    * given password is the same password in the database
    * for that user. If the user doesn't exist or if the
    * passwords don't match up, it returns an error code
    * (1 or 2). On success it returns 0.
    */
   function confirmUserPass($username, $password){
      /* Add slashes if necessary (for query) */
      if(!get_magic_quotes_gpc()) {
          $username = addslashes($username);
      }

      /* Verify that user is in database */
      $q = "SELECT password FROM ".TBL_USERS." WHERE username = '$username'";
      $result = mysql_query($q, $this->connection);
      if(!$result || (mysql_numrows($result) < 1)){
         return 1; //Indicates username failure
      }

      /* Retrieve password from result, strip slashes */
      $dbarray = mysql_fetch_array($result);
      $dbarray['password'] = stripslashes($dbarray['password']);
      $password = stripslashes($password);

      /* Validate that password is correct */
      if($password == $dbarray['password']){
         return 0; //Success! Username and password confirmed
      }
      else{
         return 2; //Indicates password failure
      }
   }
   
   /**
    * confirmUserID - Checks whether or not the given
    * username is in the database, if so it checks if the
    * given userid is the same userid in the database
    * for that user. If the user doesn't exist or if the
    * userids don't match up, it returns an error code
    * (1 or 2). On success it returns 0.
    */
   function confirmUserID($username, $userid){
      /* Add slashes if necessary (for query) */
      if(!get_magic_quotes_gpc()) {
          $username = addslashes($username);
      }

      /* Verify that user is in database */
      $q = "SELECT userid FROM ".TBL_USERS." WHERE username = '$username'";
      $result = mysql_query($q, $this->connection);
      if(!$result || (mysql_numrows($result) < 1)){
         return 1; //Indicates username failure
      }

      /* Retrieve userid from result, strip slashes */
      $dbarray = mysql_fetch_array($result);
      $dbarray['userid'] = stripslashes($dbarray['userid']);
      $userid = stripslashes($userid);

      /* Validate that userid is correct */
      if($userid == $dbarray['userid']){
         return 0; //Success! Username and userid confirmed
      }
      else{
         return 2; //Indicates userid invalid
      }
   }
   
   /**
    * usernameTaken - Returns true if the username has
    * been taken by another user, false otherwise.
    */
   function usernameTaken($username){
      if(!get_magic_quotes_gpc()){
         $username = addslashes($username);
      }
      $q = "SELECT username FROM ".TBL_USERS." WHERE username = '$username'";
      $result = mysql_query($q, $this->connection);
      return (mysql_numrows($result) > 0);
   }
   
   /**
    * usernameBanned - Returns true if the username has
    * been banned by the administrator.
    */
   function usernameBanned($username){
      if(!get_magic_quotes_gpc()){
         $username = addslashes($username);
      }
      $q = "SELECT username FROM ".TBL_BANNED_USERS." WHERE username = '$username'";
      $result = mysql_query($q, $this->connection);
      return (mysql_numrows($result) > 0);
   }
   
   /**
    * addNewUser - Inserts the given (username, password, email)
    * info into the database. Appropriate user level is set.
    * Returns true on success, false otherwise.
    */
   function addNewUser($username, $password, $email){
      $time = time();
      /* If admin sign up, give admin user level */
      if(strcasecmp($username, ADMIN_NAME) == 0){
         $ulevel = ADMIN_LEVEL;
      }else{
         $ulevel = USER_LEVEL;
      }
      $q = "INSERT INTO ".TBL_USERS." VALUES ('$username', '$password', '0', $ulevel, '$email', $time)";
      return mysql_query($q, $this->connection);
   }
   
   /**
    * updateUserField - Updates a field, specified by the field
    * parameter, in the user's row of the database.
    */
   function updateUserField($username, $field, $value){
      $q = "UPDATE ".TBL_USERS." SET ".$field." = '$value' WHERE username = '$username'";
      return mysql_query($q, $this->connection);
   }
   
   /**
    * getUserInfo - Returns the result array from a mysql
    * query asking for all information stored regarding
    * the given username. If query fails, NULL is returned.
    */
   function getUserInfo($username){
      $q = "SELECT * FROM ".TBL_USERS." WHERE username = '$username'";
      $result = mysql_query($q, $this->connection);
      /* Error occurred, return given name by default */
      if(!$result || (mysql_numrows($result) < 1)){
         return NULL;
      }
      /* Return result array */
      $dbarray = mysql_fetch_array($result);
      return $dbarray;
   }
   
   /**
    * getNumMembers - Returns the number of signed-up users
    * of the website, banned members not included. The first
    * time the function is called on page load, the database
    * is queried, on subsequent calls, the stored result
    * is returned. This is to improve efficiency, effectively
    * not querying the database when no call is made.
    */
   function getNumMembers(){
      if($this->num_members < 0){
         $q = "SELECT * FROM ".TBL_USERS;
         $result = mysql_query($q, $this->connection);
         $this->num_members = mysql_numrows($result);
      }
      return $this->num_members;
   }
   
   /**
    * calcNumActiveUsers - Finds out how many active users
    * are viewing site and sets class variable accordingly.
    */
   function calcNumActiveUsers(){
      /* Calculate number of users at site */
      $q = "SELECT * FROM ".TBL_ACTIVE_USERS;
      $result = mysql_query($q, $this->connection);
      $this->num_active_users = mysql_numrows($result);
   }
   
   /**
    * calcNumActiveGuests - Finds out how many active guests
    * are viewing site and sets class variable accordingly.
    */
   function calcNumActiveGuests(){
      /* Calculate number of guests at site */
      $q = "SELECT * FROM ".TBL_ACTIVE_GUESTS;
      $result = mysql_query($q, $this->connection);
      $this->num_active_guests = mysql_numrows($result);
   }
   
   /**
    * addActiveUser - Updates username's last active timestamp
    * in the database, and also adds him to the table of
    * active users, or updates timestamp if already there.
    */
   function addActiveUser($username, $time){
      $q = "UPDATE ".TBL_USERS." SET timestamp = '$time' WHERE username = '$username'";
      mysql_query($q, $this->connection);
      
      if(!TRACK_VISITORS) return;
      $q = "REPLACE INTO ".TBL_ACTIVE_USERS." VALUES ('$username', '$time')";
      mysql_query($q, $this->connection);
      $this->calcNumActiveUsers();
   }
   
   /* addActiveGuest - Adds guest to active guests table */
   function addActiveGuest($ip, $time){
      if(!TRACK_VISITORS) return;
      $q = "REPLACE INTO ".TBL_ACTIVE_GUESTS." VALUES ('$ip', '$time')";
      mysql_query($q, $this->connection);
      $this->calcNumActiveGuests();
   }
   
   /* These functions are self explanatory, no need for comments */
   
   /* removeActiveUser */
   function removeActiveUser($username){
      if(!TRACK_VISITORS) return;
      $q = "DELETE FROM ".TBL_ACTIVE_USERS." WHERE username = '$username'";
      mysql_query($q, $this->connection);
      $this->calcNumActiveUsers();
   }
   
   /* removeActiveGuest */
   function removeActiveGuest($ip){
      if(!TRACK_VISITORS) return;
      $q = "DELETE FROM ".TBL_ACTIVE_GUESTS." WHERE ip = '$ip'";
      mysql_query($q, $this->connection);
      $this->calcNumActiveGuests();
   }
   
   /* removeInactiveUsers */
   function removeInactiveUsers(){
      if(!TRACK_VISITORS) return;
      $timeout = time()-USER_TIMEOUT*60;
      $q = "DELETE FROM ".TBL_ACTIVE_USERS." WHERE timestamp < $timeout";
      mysql_query($q, $this->connection);
      $this->calcNumActiveUsers();
   }

   /* removeInactiveGuests */
   function removeInactiveGuests(){
      if(!TRACK_VISITORS) return;
      $timeout = time()-GUEST_TIMEOUT*60;
      $q = "DELETE FROM ".TBL_ACTIVE_GUESTS." WHERE timestamp < $timeout";
      mysql_query($q, $this->connection);
      $this->calcNumActiveGuests();
   }
   
   /**
    * query - Performs the given query on the database and
    * returns the result, which may be false, true or a
    * resource identifier.
    */
   function query($query){
      return mysql_query($query, $this->connection);
   }
};

/* Create database connection */
$database = new MySQLDB;

?>

Dormilich · 11-22-2010, 09:18 PM

a) it’s mysql_num_rows()
b) you never check whether your query succeeds or fails.

myfayt · 11-22-2010, 10:30 PM

As Dormilich said, missing one of the underscores.

Fou-Lu · 11-22-2010, 11:02 PM

MySQL_numrows is actually valid (although should be considered obsolescent); its a direct synonym to mysql_num_rows. Actually, most mysql_*_* have alias' I believe.

This is a typical error, very common. The issue as mentioned is simply that you do not check for a valid resource. This can be done as easily as:

PHP Code:


			
$qry = @mysql_query('SOMEQUERY'); 
if ($qry)
{
    if (mysql_num_rows($qry) > 0)
    {
        echo 'We have more than 0 records.';
    }
}

What matters is the check for if($qry). Trying to call mysql_num_rows on a failed query will always fail since it considers the call mysql_num_rows(false); which is always false (and triggers an error of course).

zachatk · 11-22-2010, 11:24 PM

Alright... so I replaced this line for example:

PHP Code:


			
   function calcNumActiveUsers(){
      /* Calculate number of users at site */
      $q = "SELECT * FROM ".TBL_ACTIVE_USERS;
      $result = mysql_query($q, $this->connection);
      $this->num_active_users = mysql_numrows($result);
   }

with this:

PHP Code:


			
   function calcNumActiveUsers(){
      /* Calculate number of users at site */
      $q = "SELECT * FROM ".TBL_ACTIVE_USERS;
      $result = @mysql_query($q, $this->connection);
      if ($result)
        {
          if (mysql_num_rows($result) > 0)
            {
              echo "ERROR on calcNumActiveUsers: More than one record exists";
            }
        }
   }

And I get this:

ERROR on calcNumActiveUsers: More than one record existsERROR on calcNumActiveUsers: More than one record existsERROR on calcNumActiveUsers: More than one record exists

MattF · 11-22-2010, 11:29 PM

That's checking for the existence of *any* rows. If you're wanting to check for the existence of one row only:

Code:

if (mysql_num_rows($result) > 1)

zachatk · 11-22-2010, 11:59 PM

Thanks a lot guys! I really appreciate it. Got it working nicely.

zachatk · 11-24-2010, 02:14 PM

Well I thought I had it figured out... until this:

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /home/a2986016/public_html/view_active.php on line 10

Code:

<?
if(!defined('TBL_ACTIVE_USERS')) {
  die("Error processing page");
}

$q = "SELECT username FROM ".TBL_ACTIVE_USERS
    ." ORDER BY timestamp DESC,username";
$result = $database->query($q);
/* Error occurred, return given name by default */
$num_rows = mysql_num_rows($result);
if(!$result || ($num_rows < 0)){
   echo "Error displaying info";
}
else if($num_rows > 0){
   /* Display active users, with link to their info */
   echo "<table border=\"1\" cellspacing=\"0\" cellpadding=\"3\">\n";
   echo "<tr><td><font size=\"2\">\n";
   for($i=0; $i<$num_rows; $i++){
      $uname = mysql_result($result,$i,"username");

      echo "<a href=\"infopage.php?user=$uname\">$uname</a> / ";
   }
   echo "</font></td></tr></table><br>\n";
}
?>

I tried putting Fou-Lu's script in but the if (mysql_num_rows($qry) > 0) part just gave the same error as before.

Another quick question



$this->num_active_users = mysql_num_rows($result);

Would putting that in here like this be the same as before (post #5 first code).

Code:

$qry = @mysql_query('SOMEQUERY'); 
if ($qry)
{
    if (mysql_num_rows($qry) > 1)
    {
        echo 'We have more than 1 records.';
    }
  $this->num_active_users = mysql_num_rows($qry);
}

I have to have that for everywhere on the site where it uses those variables.

Dormilich · 11-24-2010, 02:18 PM

you would have to test each and every query call for errors, otherwise the mentioned warning occurs.

PS. that’s what I like in PDO, you can set it to automaticly throw Exceptions when there is an error

zachatk · 11-24-2010, 04:41 PM

So... how do I do that?

PDO... never heard of it. How hard would it be to switch over to it.

Dormilich · 11-24-2010, 07:20 PM

Quote:

Originally Posted by zachatk

PDO... never heard of it.

http://php.net/pdo

Quote:

Originally Posted by zachatk

How hard would it be to switch over to it.

if you’re somewhat familiar with objects — not complicated
if you’ve heard of Iterators — piece of cake

Quote:

Originally Posted by zachatk

So... how do I do that?

PHP Code:


			
$dsn = "mysql:host=$host;dbname=$dbname";

$pdo = new PDO($dsn, $login, $password);

$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);