Blog demo code

conn.php

<?php
// connect to database
$con = mysqli_connect('host', 'user', 'password', 'db_name');

// check for connection errors
if(mysqli_connect_errno())
	die(mysqli_connect_error());

// function to execute query and automatically check for errors
function query($sql){
	$result = mysqli_query($GLOBALS['con'], $sql);

	if(!$result){
		die(mysqli_error($GLOBALS['con']));
	}

	return $result;
}