<?php

/* interface contains only fixed-name declarations/stubs in with no access levels, yet it allows public,
 * no ctors, no data members, no method definitions, no restriction on who implements this interface
 *
 */
interface iDB {
    const MAX_RECORDS = 5000;
    public function query();
    public function drop();
}

class MyDBDriver implements iDB {
    public function query() {
        echo "querying" . PHP_EOL;
    }
    public function drop() {
        echo "dropping" . PHP_EOL;
    }
}

$db = new MyDBDriver();
$db->query() . PHP_EOL;
$db = NULL;