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I have read these pages

I know basic about URL,URN,URI! and little on their difference! but the thing I cannot understand is in a page like: http://www.bernzilla.com/item.php?id=100 which part is URL,URN and URI!
URI is whole part but URL and URN??
picture from wikipedia

Edit: from w3c.org:
a URL is a type of URI that identifies a resource via a representation of its primary access mechanism (e.g., its network "location"), rather than by some other attributes it may have.

from www.damnhandy.com:

it is now considered incorrect to use URL when describing applications.

Now is id an attribute?what about application part? is php an application?

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This question has been asked on Stack Overflow a few times and got a good deal of attention and good responses: What's the difference between a URI and a URL? –  hippietrail Dec 21 '12 at 10:12

2 Answers 2

I think those articles explain quite well. To answer your question - all of this is a URL:


Each bit of it - http: www.bernzilla.com and so on has it's own name:

  • http: is the scheme
  • www is the sub-domain
  • bernzilla.com is the domain
  • com is the top level domain or TLD
  • (there could be a folder or path there, e.g. /dir/item.php but there isn't)
  • item.php is the page or filename which has an extension php
  • id=100 is the query string

I can see given that diagram from wikipedia why you're asking though. That diagram is saying there are two types of URI - URLs and URNs and the fuzzy bit in the middle is when something can be both.

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Thanks for answer. I edited my question. can you take look again? –  undone Sep 2 '11 at 13:35
I don't understand that quote about describing applications and I can't see a comment where someone points that out. I'll update my answer to describe the separate parts. –  paulmorriss Sep 2 '11 at 13:53
@paul don't you mean URI in the first line? id=100 isn't a location, it's an indicator. –  DisgruntledGoat Sep 7 '11 at 14:37
I think I meant URL. With some sites if you change the id you get different "pages" in normal-speak. Reading the definition of resource on wikipedia I think a page is an example of a resource. –  paulmorriss Sep 7 '11 at 14:43

It is not the case that the URL you mention is composed of both a URL and URN part.

http://www.bernzilla.com/item.php?id=100 is both a URL and a URI.

Basically URIs are a superset of URLs and of URNs. There is some overlap between URLs and URNs as well.

A URI identifies a resource either by location, or a name, or both.

So any URL is a URI, any URN is a URI, but not every URI is a URL.

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