Choosing a Namespace URI

The first choice to make is the URI scheme. While theoretically any URI scheme can be used, in practice only two are at all common: http and urn. An http scheme is the familiar http URL that is loaded into web browsers, printed in books, advertised on the sides of buses, and painted on building walls. A URN scheme, by contrast, identifies a Uniform Resource Name (as opposed to a Uniform Resource Locator). According to the URN specification, RFC 2141, URNs “are intended to serve as persistent, location-independent, resource identifiers.”[1] Here are a few examples of URNs:

[1] R. Moats (ed.). “URN Syntax.” 1997. Accessed online in June 2003 at

  • urn:uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882 ...

Get Effective XML: 50 Specific Ways to Improve Your XML now with the O’Reilly learning platform.

O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.