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警告:mysqli_num_rows()期望参数1为mysqli_result,null中给出null

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我试图将我的mysql更改为mysqli . 当我这样做时,我得到错误 . 我尝试了一切,但我找不到解决方案 .

我遇到的错误:(你看到的不是所有的错误)

警告:mysqli_query()要求参数1为mysqli,在第219行的C:\ xampp \ htdocs \ follow \ include \ database.php中给出null警告:mysqli_num_rows()要求参数1为mysqli_result,在C中给出null:第220行\ xampp \ htdocs \ follow \ include \ database.php警告:mysqli_query()期望参数1为mysqli,在第231行的C:\ xampp \ htdocs \ follow \ include \ database.php中给出null警告:mysqli_num_rows ()期望参数1为mysqli_result,在第232行的C:\ xampp \ htdocs \ follow \ include \ database.php中给出null警告:mysqli_query()期望参数1为mysqli,在C:\ xampp \ htdocs中给出null \在102行跟随\ include \ database.php ...更多错误

这是我的PHP代码

<?php
/**
 * Please subscribe to our feeds at http://blog.geotitles.com for more such tutorials
 */
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 */

 $con = mysqli_connect(DB_SERVER, DB_USER, DB_PASS,DB_NAME);

  // Check connection
 if (mysqli_connect_errno())
     {
   echo "Failed to connect to MySQL: " . mysqli_connect_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();
    }
   }


   function confirmUserPass($username, $password){
   GLOBAL $con;
   /* 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'";
   $result = mysqli_query($con,$q);
   if(!$result || (mysqli_num_rows($result) < 1)){
     return 1; //Indicates username failure
   }

   /* Retrieve password from result, strip slashes */
   $dbarray = mysqli_fetch_array($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
  }
  } 


   function confirmUserID($username, $userid){
   GLOBAL $con;
  /* 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'";
  $result = mysqli_query($con,$q);
  if(!$result || (mysqli_num_rows($result) < 1)){
     return 1; //Indicates username failure
   }

  /* Retrieve userid from result, strip slashes */
  $dbarray = mysqli_fetch_array($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
  }
  }


  function usernameTaken($username){
   GLOBAL $con;
    if(!get_magic_quotes_gpc()){
     $username = addslashes($username);
   }
  $q = "SELECT username FROM ".TBL_USERS." WHERE username = '$username'";
  $result = mysqli_query($con,$q);
  return (mysqli_numrows($result) > 0);
  }


 function usernameBanned($username){ 
 GLOBAL $con;
  if(!get_magic_quotes_gpc()){
     $username = addslashes($username);
  }
  $q = "SELECT username FROM ".TBL_BANNED_USERS." WHERE username = '$username'";
  $result = mysqli_query($con,$q);
  return (mysqli_numrows($result) > 0);
  }

function addNewUser($username, $password, $email){
GLOBAL $con;
  $time = time();
  /* If admin sign up, give admin user level */
  if(strcasecmp($username, ADMIN_NAME) == 0){
     $ulevel = ADMIN_LEVEL;
  }else{
     $ulevel = USER_LEVEL;
  }
  $q = "INSERT INTO ".TBL_USERS." VALUES ('$username', '$password', '0', $ulevel,     '$email', $time)";
  return mysqli_query($con,$q);
  }


 function updateUserField($username, $field, $value){
  $q = "UPDATE ".TBL_USERS." SET ".$field." = '$value' WHERE username = '$username'";
  return mysqli_query($con,$q);
}


   function getUserInfo($username){
 GLOBAL $con;
  $q = "SELECT * FROM ".TBL_USERS." WHERE username = '$username'";
  $result = mysqli_query($con,$q);
  /* Error occurred, return given name by default */
  if(!$result || (mysqli_num_rows($result) < 1)){
     return NULL;
  }
  /* Return result array */
  $dbarray = mysqli_fetch_array($result);
  return $dbarray;
  }


 function getNumMembers(){
 GLOBAL $con;
  if($this->num_members < 0){
     $q = "SELECT * FROM ".TBL_USERS;
     $result = mysqli_query($con,$q);
     $this->num_members = mysqli_num_rows($result);
   }
  return $this->num_members;
  }

    /**
   * calcNumActiveUsers - Finds out how many active users
   * are viewing site and sets class variable accordingly.
   */
   function calcNumActiveUsers(){
 GLOBAL $con;
  /* Calculate number of users at site */
  $result = mysqli_query($con,"SELECT * FROM ".TBL_ACTIVE_USERS);
  $this->num_active_users = mysqli_num_rows($result);
     }


  function calcNumActiveGuests(){  
  GLOBAL $con;
  /* Calculate number of guests at site */
  $q = "SELECT * FROM ".TBL_ACTIVE_GUESTS;
  $result = mysqli_query($con,$q);
  $this->num_active_guests = mysqli_num_rows($result);
   }


   function addActiveUser($username, $time){
 GLOBAL $con;
  $q = "UPDATE ".TBL_USERS." SET timestamp = '$time' WHERE username = '$username'";
  mysqli_query($con,$q);

  if(!TRACK_VISITORS) return;
  $q = "REPLACE INTO ".TBL_ACTIVE_USERS." VALUES ('$username', '$time')";
  mysqli_query($con,$q);
  $this->calcNumActiveUsers();
   }

 function addActiveGuest($ip, $time){
 GLOBAL $con;
  if(!TRACK_VISITORS) return;
  $q = "REPLACE INTO ".TBL_ACTIVE_GUESTS." VALUES ('$ip', '$time')";
  mysqli_query($con,$q);
  $this->calcNumActiveGuests();
   }

 function removeActiveUser($username){
 GLOBAL $con;
  if(!TRACK_VISITORS) return;
  $q = "DELETE FROM ".TBL_ACTIVE_USERS." WHERE username = '$username'";
  mysqli_query($con,$q);
  $this->calcNumActiveUsers();
   }

/* removeActiveGuest */
function removeActiveGuest($ip){
GLOBAL $con;
  if(!TRACK_VISITORS) return;
  $q = "DELETE FROM ".TBL_ACTIVE_GUESTS." WHERE ip = '$ip'";
  mysqli_query($con,$q);
  $this->calcNumActiveGuests();
}

/* removeInactiveUsers */
function removeInactiveUsers(){
GLOBAL $con;
  if(!TRACK_VISITORS) return;
  $timeout = time()-USER_TIMEOUT*60;
  $q = "DELETE FROM ".TBL_ACTIVE_USERS." WHERE timestamp < $timeout";
  mysqli_query($con,$q);
  $this->calcNumActiveUsers();
}

/* removeInactiveGuests */
function removeInactiveGuests(){
 GLOBAL $con;
  if(!TRACK_VISITORS) return;
  $timeout = time()-GUEST_TIMEOUT*60;
  $q = "DELETE FROM ".TBL_ACTIVE_GUESTS." WHERE timestamp < $timeout";
  mysqli_query($con,$q);
  $this->calcNumActiveGuests();
}


function query($query){
GLOBAL $con;
  return mysqli_query($con,$query);
}
};


  $database = new MySQLDB;

  ?>

2 回答

  • 1

    你在构造函数中定义了 $con (因为你为它准备了一个变量,你应该存储在 $this->connection 中) . 因为它是在函数中定义的,所以它不是全局变量,因此无法使用 global $con; 导入 . 如果你在任何地方正确使用 $this->connection 你使用连接处理程序,那么它应该工作 .

  • 3

    错误相当模糊,但具体 . 它声明连接对象 mysql_result 是预期的,但它正在接收 null .

    原因是你试图在每个函数中使用连接:

    global $con;
    mysqli_query($con, $q);
    

    global 关键字会将全局变量引入您正在使用它的函数中,但是 $con 不需要在类中使用 global ) . 你要找的是 $this 关键字 .

    在类构造函数 MySQLDB() 中定义 $con 变量;你应该改为使用 $this->connection ,因为你已经定义了一个名为 $connection 的全局变量:

    $this->connection = mysqli_connect(DB_SERVER, DB_USER, DB_PASS,DB_NAME);
    

    然后,在每个函数中,而不是使用类似的东西:

    global $con;
    mysqli_query($con,$q);
    

    您可以使用:

    mysqli_query($this->connection, $q);
    

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