我不确定这里出了什么问题。我只是按照在线教程进行操作,然后就出现了这些错误。
我收到以下错误
错误
Notice: Undefined variable: db in C:\xampp\htdocs\wisconsindairyfarmers\admin\login.php on line 7
Fatal error: Call to a member function query() on null in C:\xampp\htdocs\wisconsindairyfarmers\admin\login.php on line 7
代码
<?php
$db = new mysqli('127.0.0.1', 'root', '', 'wisconsindairyfarmers');
?>
<?php
require '../db/connect.php';
require '../functions/general.php';
function user_exists($username){
//$username = sanitize($username);
$result = $db->query("SELECT COUNT(UserId) FROM users WHERE UserName = '$username'");
if($result->num_rows){
return (mysqli_result($query, 0) == 1) ? true : false;
}}
if(empty($_POST) === false){
$username = $_POST['username'];
$password = $_POST['password'];
if(empty($username) === true || empty($password) === true){
echo 'You need to enter a username and password';
}
else if(user_exists($username) === false) {
echo 'We can\'t find that username.';
}
}
?>
首先,您在函数外部声明了 $db。如果你想在函数内部使用它,你应该将它添加为另一个参数:
function user_exists($db, $username){
...
而不是这样称呼它:
user_exists($db, $username)
将此行放入父构造中:$this->load->database();
function __construct() {
parent::__construct();
$this->load->library('lib_name');
$model=array('model_name');
$this->load->model($model);
$this->load->database();
}
这样..应该可以工作..