在函数外部使用变量

Question

this is probebly a silly question but I don't know where else to ask this. I need to call on $conn in the functions below, but if I try to turn it into a global it doesn't work. If someone can explain to me how to use an outside variable inside a function I'd be very grateful.

Here's my little piece of code:

<?php
error_reporting(E_ALL);
ini_set('display_errors', 1);
 //Maak connectie met database
 $host = "localhost";
 $username = "i266161_studie";
 $password = "studie";
 $dbnaam = "test";
 $fout = "Error: Failed to open database";

 $conn = mysqli_connect($host, $username, $password, $dbnaam)
 or die ("Connection failed: ".mysqli_connect_error()); 

function insert_once($conn){
$query = 'INSERT INTO gebruikers (naam, leeftijd, woonplaats)
VALUES ("Henk", 17, "Eindhoven")';
mysqli_query($conn,$query);
}

function insert_twice($conn){
$query = 'INSERT INTO gebruikers (naam, leeftijd, woonplaats)
VALUES ("Bert", 21, "Helmond"), ("Ruud", 32, "Helmond")';
mysqli_query($conn,$query);
}
insert_twice();

?>

Answer 1

don't use globals unless you REALLY have to! don't forget to pass your $conn parameter to your functions e.g.

change this:

insert_twice();

to this:

insert_twice($conn);

I'd suggest adding some error handling to your mysql_query() calls too, you should not assume that these are always successful