我刚开始学习OOP,在使用教程时遇到了以下错误:
Warning: Missing argument 2 for MySQLDatabase::query(), called in
/Applications/MAMP/htdocs/object-oriented/public/index.php on line 7 and defined in
/Applications/MAMP/htdocs/object-oriented/includes/database.php on line 28
Notice: Undefined variable: sql in
/Applications/MAMP/htdocs/object-oriented/includes/database.php on line 29
Warning: mysqli_query() expects parameter 1 to be mysqli, null given in
/Applications/MAMP/htdocs/object-oriented/includes/database.php on line 29
这是我的数据库.php
<?php
require('config.php');
class MySQLDatabase {
public $connection;
public function open_connection() {
$this->$connection = mysqli_connect('DB_SERVER', 'DB_USER', 'DB_PASS');
if (!$this->connection) {
die("Database connection failed");
} else {
$db_select = mysqli_select_db($this->connection, DB_NAME);
if (!$select_db) {
die("Database selection failed");
}
}
}
public function close_connection() {
if (isset($this->connection)) {
mysqli_close($this->connection);
unset($this->connection);
}
}
public function query($connection, $sql) {
$result = mysqli_query($this->connection, $sql);
$this->confirm_query($result);
return $result;
}
以及我的index.php,我正试图在其中测试query()方法。
$sql = "INSERT INTO users (id, username, password, first_name, last_name) ";
$sql .= "VALUES (1, 'andrei', 'password', 'Andrei', 'Popa')";
$result = $database->query($sql);
$sql = "SELECT * FROM users WHERE id = 1";
$result_set = $database->query($sql);
$found_user = mysqli_fetch_array($result_set);
echo "Found user!" . $found_user['username'];
知道我做错了什么吗?感谢
public function query($connection, $sql) {
您不需要第一个参数,因为连接是类的属性。因此,只将$sql
传递到查询方法中,就像您在使用方法时所做的那样
public function query($sql) {
这是您的定义:
public function query($connection, $sql) {
这是你的电话:
$result = $database->query($sql);
您需要添加一个连接:)
您有许多错误:
第一个
$db_select = mysqli_select_db($this->connection, DB_NAME);
if (!$select_db) {
检查变量db_select
和select_db
第二:
public function query($connection, $sql) {
$result = $database->query($sql);
你需要核实你的论点。我认为,你需要从申报中删除$connection
public function query($sql) {
因为接下来您将使用类变量:
$this->connection;
第三:
public function open_connection()
您的类中没有构造函数,也没有调用方法open_connection
,因此:您的活动连接是NULL
你需要将这个方法添加到你的类中:
function __construct() {
open_connection();
}