Much like directories and files, PHP namespaces also contain the ability to specify a hierarchy of namespace names. Thus, a namespace name can be defined with sub-levels:
Example #1 Declaring a single namespace with hierarchy
<?php namespace MyProject\Sub\Level;
const CONNECT_OK = 1; class Connection { /* ... */ } function connect() { /* ... */ }
?>
The above example creates constant MyProject\Sub\Level\CONNECT_OK, class MyProject\Sub\Level\Connection and function MyProject\Sub\Level\connect.
PHP General