php函数数据库连接

Question

我正在使用php函数与mysql数据库连接挣扎。我似乎无法调用数据库连接并返回任何数据。有什么想法吗？

<?php
$useID=$_POST['use_id'];

function dbConnect(){
$conn= mysqli_connect("localhost", "name", "pword", "path");
// Check connection
if (!$conn) {
   die("Connection failed: " . mysqli_connect_error());
}
return $conn;
}

function dropDown(){
$conn=dbConnect();
$query="SELECT * FROM usesList";
$myData = mysqli_query($conn, $query);
$row=mysqli_fetch_array($myData);
$options="";

while ($row=mysqli_fetch_array($myData)) {
  $options.="<option value='" . $row['use_id'] ."' >" . $row['use_name'] ."    
</option>";
 }
}
dropDown();?>