MongoDB

• Every document needs a unique, immutable ID

• ID consists of: 4-byte timestamp, 3-byte machine identifier, 2-byte PID and 3-byte counter:


<?php
$m = new MongoClient();
$c = $m->demo->articles;

$c->insert( [ 'name' => 'Derick', '_id' => 'derickr' ] );

$d = [ 'name' => 'Derick' ];
$c->insert( $d );
var_dump( $d );
?>

Output