問題描述

我在 functions.php 中有一個函數(shù)列表.我正在從 Mysql 升級到 Mysqli 因為我剛剛學習的 Mysql 現(xiàn)在已經(jīng)貶值了.

I have a list of functions in functions.php. I'm upgrading from Mysql to Mysqli because I just learning Mysql is now depreciated.

我在頂級connect.php 文件中聲明了我的連接.需要第一個文件.

I declare my connection in a top levelconnect.php file. The first file required.

無論如何回到我所有的函數(shù)都使用 mysql_query("QUERY") 并且總是工作正常的點.現(xiàn)在我將它們?nèi)扛臑?

Anyway back to the point all my functions use mysql_query("QUERY") and that always worked fine. Now I changed all them to:

$con->query("QUERY") // ($con is my connection variable)

現(xiàn)在我得到一個

致命錯誤:在第 241 行調(diào)用 C:wampwwwPHPfunctions.php 中非對象的成員函數(shù) query()

Fatal error: Call to a member function query() on a non-object in C:wampwwwPHPfunctions.php on line 241

如果我在整個文件中聲明我的變量，我不明白為什么我可以查詢.它應該可以在任何地方訪問，我只是不確定.這使我的網(wǎng)站暫停，直到我能解決這個問題.這是來自 functions.php

I don't get why I can query if I'm declaring my variable in my whole file. It should be accessible everywhere, I'm just not sure. This has put my website on hold until I can fix this. Here is a sample function from functions.php

function getSiteName()
{
    $row = $con->query("SELECT * FROM siteinfo")->fetch_array();
    return $row["siteName"];
}

我的連接:

global $con ;
$con = new mysqli("localhost", "itunes89", "XXXX","projectanvil") or die("Sorry, were having server connection issues. Please try again later.");

推薦答案

那是一個 變量作用域問題.您需要將 $conn 傳遞給 getSiteName():

That's a variable scope problem. You need to pass $conn to getSiteName():

function getSiteName($con) {
    $row = $con->query("SELECT * FROM siteinfo")->fetch_array();
    return $row["siteName"];
}

$name = getSiteName($con);

或者使用帶有構造函數(shù)注入的類:

Or using a class with constructor injection:

class MyThing
{
    protected $con;

    public function __construct($con) {
        $this->con = $con;
    }

    public function getSiteName() {
        $row = $this->con->query("SELECT * FROM siteinfo")->fetch_array();
        return $row["siteName"];
    }
}

$obj = new MyThing($con);
$name = $obj->getSiteName();

在整個課程中，您可以使用 $this->con 來訪問連接.

Throughout the class you can use $this->con to access the connection.

這篇關于函數(shù)中的 Mysqli 查詢 - PHP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)！