As with any database system the first thing you must do is open a database. Since SQLite is based on files, opening a database differs very little from opening a regular file.

<?php
    /* resource sqlite_open(string filename [, int mode [, string &error_message]]) */
    $db = sqlite_open("db.sqlite", 0666, $error) 
        or die("Failed to connect because: ".$error);
    /* opened a connection to memory only database */
?>