# Base: http://bblfish.net/work/atom-owl/2004-08-12/
@prefix xsd:     <http://www.w3.org/2001/XMLSchema#> .
@prefix rdf:     <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix foaf:    <http://xmlns.com/foaf/0.1/> .
@prefix :        <http://bblfish.net/work/atom-owl/2004-08-12/Atom.owl#> .

<http://bblfish.net/work/atom-owl/2004-08-12/entry.2004-08-13-1445.n3>
      a       :Entry ;
      :alternate
              [ a       :Link ;
                :href   <http://bblfish.net/work/atom-owl/2004-08-12/blogexample.html#entry.2004-08-13-1445.n3> ;
                :mime-type "text/html"^^xsd:string ;
                :text   "html blog entry"^^xsd:string
              ] ;
      :author [ a       foaf:Person ;
                foaf:homepage <http://bblfish.net/> ;
                foaf:mbox <mailto:henry.story@bblfish.net> ;
                foaf:name "Henry Story"^^xsd:string
              ] ;
      :content
              [ a       :Content ;
                :data   "The current model proposes two view on an entry: <ul><li>the simple Entry, that can be found at a certain retrievable location, and shows only its current state.<li>the Entry as a historical thing, that encompasses all the changes that occurred to it in the actualworld (we don't deal with <a href='http://en.wikipedia.org/wiki/David_Lewis_%28philosopher%29'>counterfactual</a> entries). This is the EntryID and its associated EntryVersion-s.</ul>This is illustrated by the following diagram:<p><img src='Atom-FOAF-twoEntries.jpg'><p>Again I have tried to highlight the two areas by placing their classes on differently colored backgrounds. On the yellow background is the main class for the temporal Entry representation, and on the green background, we have the atemporal Entry Representation. Given any one of these one can deduce the other. Ie, they are  logical consequences of one another.<p> Some of the main points distinguishing them are: <ul> <li> An entry has a URL resource, that allows one to fetch the information (for example a  relative uri such as <a href='entry.2004-06-29-1010.n3'>entry.2004-06-29-1010.n3</a>),  whereas EntryID and EntryVersions are URNs such as <u>tag:bblfish.net/20040629/1010/blog1#version1</u> which will indeed uniquely identify an Entry, but will not allow one to retrieve them without a search engine. This difference creates a fundamental difference in use between these two ways of looking at the entry. An Entry is what people should be editing and fetching in a RESTful manner using GET, POST, and PUT. An EntryID is how a client would identify the Entry-s it downloaded to keep track of the changes to them, and that to which they were responding, so it could follow how the entry  propagated around the web, etc. The EntryID and EntryState classes are key elements in databases such as <a href='AllInOneDatabase.n3'>AllInOneDatabase.n3</a>, which contains all the information about all the  entries in this directory.  <li> An entry must have an id and of course an entry-version. The unchanging parts of the Entry, its  essential properties, go into the EntryID structure. The contingent properties of an Entry go into the EntryVersion. An EntryID may on the other hand have a number of EntryVersion-s. Each of these EntryVersions represents the state of the Entry over a particular span of time. From an Entry one can easily deduce the EntryVersion and EntryID fields. To go in the opposite direction one first needs to select the latest EntryVersion of an EntryID. <li>An Entry can be a reply to another EntryVersion. It is important to keep track of which version of an entry one is replying to, as this can significantly change the meaning of a response. For clients this could help clients flag responses that might need to be updated or even deleted, or it could help readers beware that a response may no longer be relevant to the entry it is relating to. </ul>"^^xsd:string ;
                :mime-type "text/html"^^xsd:string
              ] ;
      :copyright <http://creativecommons.org/licenses/by-sa/2.0/> ;
      :created "2004-08-13T14:45:00+0200"^^xsd:dateTime ;
      :entry-version <tag:bblfish.net/20040813/1445/blog1#version1> ;
      :id     <tag:bblfish.net/20040813/1445/blog1> ;
      :title  [ a       :Content ;
                :data   "Two perspectives on a blog entry"^^xsd:string ;
                :mime-type "text/simple"^^xsd:string
              ] .