I Can't Connect to mysql

[Orlando Ballestas]

This is the code I have in my php file and the output I get:

<?php
$link = mysqli_connect('localhost', 'root', 'password', 'world');

/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}

if (!mysqli_query($link, "SET a=1")) {
printf("Errormessage: %s\n", mysqli_error($link));
}

/* close connection */
mysqli_close($link);
?>

The error I get is :
Connect failed: Unknown database 'world'

Please help me someone out there. Thanks a lot