問題描述

我需要幫助弄清楚為什么這是錯誤

I need help to figure out why this is error

<?php
    class data
    {
        private $db;
        public $nama, $password, $alamat, $jk, $kodepos, $alasan, $email;
        function _construct($db)
        {
            $this->db = $db;
        }
        public function input_data()
        {
            $query = "INSERT INTO data (nama, password, alamat, jeniskelamin, kodepos, alasan, email)VALUES('$this->nama', '$this->password',
            '$this->alamat', '$this->jk', '$this->kodepos', '$this->alasan', '$this->email')";
            $insert = mysqli_query($this->db, $query);
            return $insert;
        }
        public function lihat_data()
        {
            $query = "SELECT * FROM data ORDER BY id";
            $view = mysqli_query($this->db, $query);
            return $view;
        }
    }
?>

推薦答案

您的警告表示您的連接失敗！那是因為它從未被制作過！

Your warning means that your connection has failed! And that's because it was never made!

function __construct($db) {
       //^^You need 2 underscores
    $this->db = $db;
}

還有為什么 __construct() 需要 2x 下劃線?因為這是一種神奇的方法！以及手冊中的引用:

Also why does __construct() needs 2x underscores? Because it's a magic method! And a quote from the manual:

注意:PHP 保留所有以 __ 開頭的函數(shù)名作為魔法.建議您不要在 PHP 中使用帶有 __ 的函數(shù)名，除非您需要一些文檔化的魔法功能.

Caution: PHP reserves all function names starting with __ as magical. It is recommended that you do not use function names with __ in PHP unless you want some documented magic functionality.

有關(guān)魔術(shù)方法的更多信息，請參閱:http://php.net/手冊/en/language.oop5.magic.php
有關(guān)構(gòu)造函數(shù)的更多信息，請參閱:http://php.net/manual/en/language.oop5.decon.php

For more information about magic methods see: http://php.net/manual/en/language.oop5.magic.php
For more information about the constructor see: http://php.net/manual/en/language.oop5.decon.php

這篇關(guān)于警告:mysqli_query() 期望參數(shù) 1 為 mysqli，第 14 行 C:xampphtdocsFinaldata.php 中給出的 null的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網(wǎng)！