getting fatal error in php - php

Question

I am trying to resolve this issue. But couldnt do it. Please help
I am trying to view all the records in my database, but getting " Fatal error: Call to a member function query() on a non-object ...." and its pointing to
if ($result = $mysqli->query("SELECT ProductName, Description, Price, Size FROM Products ORDER BY ProductID"))
Here is my Complete code
<?php
include('db_connect.php');
**$mysqli = new mysqli("localhost", "netelmbn", "password", "netelmbn");
if ($mysqli->connect_errno) {
printf("Connect failed: %s\n", $mysqli->connect_error);
exit();
}**
if ($result = $mysqli->query("SELECT ProductName, Description, Price, Size FROM Products ORDER BY ProductID"))
{
if ($result->num_rows > 0)
{
echo "<table border='1' cellpadding='10'>";
echo "<tr><th>ProductID</th><th>ProductName</th><th>Description</th><th>Price</th><th>Size</th></tr>";
while ($row = $result_fetch_object())
{
echo "<tr>";
echo "<td>" . $row->ProductID . "</td>";
echo "<td>" . $row->ProductName . "</td>";
echo "<td>" . $row->Description . "</td>";
echo "<td>" . $row->Price . "</td>";
echo "<td>" . $row->Size . "</td>";
echo "<td><a href='records.php?ProductID=" . $row->ProductID . "'>Edit</a></td>";
echo "<td><a href='delete.php?ProductID=" . $row->ProductID . "'>Delete</a></td>";
echo "</tr>";
}
echo "</table>";
}
else
{
echo "No results to display!";
}
}
else
{
echo "Error: " . $mysqli->error;
}
$mysqli->close();
?>

Answer 1

You must have some database class, check at your code.
$mysqli = new Database();
$mysqli->connect();
before you execute your query:
$result = $mysqli->query("SELECT ProductName, Description, Price, Size FROM Products ORDER BY ProductID");
As you can see, query goes first, then the connection resource. >> So, Connect first.

Answer 2

You need to instantiate your $mysqli obect first. You're also not opening the database anywhere.
You need, at least, something like:
$mysqli = new ClassName( /*some parameters here*/ );
$mysqli->database_open( /* some parameters here */); // or something like this, look at the clas definition