如何使用包含連接時從MysQl Dabase中獲取？

Question

正在使用包含連接文件來連接數據庫。我的挑戰是我如何從數據庫中獲取這個卡在哪裏。

include 'connection.php'; 

$sql= 'SELECT * FROM country'; 
$results = mysqli_query($sql) 

Answer 1

假設你connection.php包含

<?php 
     $con = mysqli_connect("localhost","my_user","my_password","my_db"); 

     if (mysqli_connect_errno()) 
     { 
       echo "Failed to connect to MySQL: " . mysqli_connect_error(); 
     } 
    ?> 

所以，在你的文件，你使用include 'connection.php'獲取連接。現在通過使用include其行爲像單頁。那麼你要使用它像下面

require_once 'connection.php'; 

    $sql= 'SELECT * FROM country'; 
    $results = mysqli_query($con, $sql); # add connection string to query 

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說明

當您添加此include 'connection.php';那麼無論在父數據（connection.php）文件（例如：變量，函數，等等。）會來的孩子。

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鏈接指

1. In PHP, how does include() exactly work?
2. Are PHP include paths relative to the file or the calling code?
3. include, include_once, require or require_once?