PHP：无法在函数中使用全局变量来连接mysqli

Question

I've been searching stack to get my answer, but nothing fixed my problem. So here's my shot:

$conn = mysqli_connect('localhost', 'username', 'pass', 'db');
function GetArticle() {
  global $conn;
  $sql = "sql query";
  $getresult = mysqli_query($conn, $sql);
  ..
}

This doesn't seem to work. If I put $conn inside the function, it works fine.

Any ideas?

Answer 1

I don't know your exact situation, but in general I do not see the benefit to using $conn as global. Your function depends on a mysqli connection in order to work, so just make the connection a function parameter.

function GetArticle($conn) {
  $sql = "sql query";
  $getresult = mysqli_query($conn, $sql);
  ..
}

Then after you have established your connection, you can call the function with your connection object as its argument.

$conn = mysqli_connect('localhost', 'username', 'pass', 'db');
$article = GetArticle($conn);

I think this is a more manageable approach than trying to keep track of whether $conn is available in global scope before calling the function.