php - 我的类(class)无法连接到数据库？

Question

我正在尝试连接到我的数据库，但无法连接。我尝试过但无法连接。我得到的错误是解析错误:语法错误，第 3 行 C:\htdocs\www\dating\index.php 中出现意外的“连接”(T_STRING)。我调用了尝试过的 new Database connect();并尝试连接()；我收到此消息 Fatal error: Call to undefined function connect() in C:\htdocs\www\dating\index.php on line 3。出了什么问题？

class Database{
private $db_host = "localhost";
private $db_user = "123346";
private $db_pass = "12345";
private $db_name =  "1234";
public  $conn;
// Create connection
public function connect(){
    if(!isset($this->conn)){
        $this->conn = new mysqli_connect($this->db_host,$this->db_user,$this->pass,$this->db_name);

        if($this->conn){
            $this->conn = true;
            return true;
        }else{
            $this->conn = false;
            return false;
        }
    }
}
public function disconnect(){
    if(isset($this->conn)){
        if(mysqli_close($this->conn)){
            $this->myconn = false; 
            echo "connection closed";
            return true; 
        } else{
            echo "failed to close connection";
            return false; 
            }
        }else{
        echo "no connection prescent";
        }
    }

}

我现在尝试获取 use 查询，但它不会得到结果。这是代码

 include("functions/connect.php");
 $db = new Database("localhost", "12345", "1234", "123");
 $db->connectdb();
 $db->select('rpg');


/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}

$query = "SELECT id, username FROM users ORDER by ID DESC ";



if ($result = $db->query($query)) {

/* fetch object array */
while ($row = $result->fetch_row()) {
    printf ("%s (%s)\n", $row[0], $row[1]);
}

/* free result set */
$result->close();
}
 /* close connection */
$db->close();`

Answer 1

请更改此行

$this->conn = new mysqli_connect($this->db_host,$this->db_user,$this->pass,$this->db_name);

到此

$this->conn = new mysqli_connect($this->db_host,$this->db_user,$this->db_pass,$this->db_name);

您会注意到您使用了$this->pass，但它应该是$this->db_pass。

<小时/>

要调用Database类的函数，你必须这样编写代码；

<?php
include("functions/connect.php");

$db_conn = new Database();
if($db_conn->connect()) {
  echo "Database connected";
}