Projects/Nepomuk/Uris - Revision history

AnneW: Marked this version for translation

2012-12-10T17:35:48Z

Marked this version for translation

AnneW: Prepare for translation

2012-12-10T17:35:39Z

Prepare for translation

Vishesh at 10:33, 24 August 2012

2012-08-24T10:33:21Z

Vishesh: Fix headers

2012-08-24T10:21:15Z

Fix headers

VHanda at 14:58, 14 July 2011

2011-07-14T14:58:30Z

VHanda: /* What about the Semantic Web? */

2011-07-14T14:23:40Z

‎What about the Semantic Web?

VHanda at 14:22, 14 July 2011

2011-07-14T14:22:49Z

VHanda: /* You're lying! I see resource URIs like 'akonadi:?item=21' */

2011-07-14T14:19:45Z

‎You're lying! I see resource URIs like 'akonadi:?item=21'

VHanda: First draft - Seems more like an FAQ

2011-07-14T14:17:14Z

First draft - Seems more like an FAQ

New page

= Nepomuk URIs =

This document describes in depth how URIs are stored in Nepomuk, and their significance.

== What is a URI? ==

A URI or Uniform Resource Identifier is a string of characters used to identify or locate a resource. URIs can be of two types, or both - URNs and URLs. A URN, Uniform Resource Name, is a unique way of identifying a resource. It does not provide any information about how the resource can be found, example - urn:isbn:0374193681. A URL, Uniform Resource Locator, provides a way to access the resource. Example - file:///home/user/file. This url clearly dictates that the 'file' protocol should be used along with the path '/home/user/file'. It does not give a unique way of identifying the resource. It just provides one way to access the resource.

== So what does Nepomuk use? ==

Nepomuk URIs are in a way URNs, though unlike conventional URNs which provide a globally unique way of identifying a resource, they provide a unique way of identifying a resource '''on one machine'''. This is important - Nepomuk URIs are NOT machine independent. The same resource can have different URIs on different systems. This is because all URIs in Nepomuk are randomly generated. They follow a pattern -

`nepomuk:/TYPE/uuid`

where TYPE is either *res* or *ctx*. UUID stands for a Universally Unique Identifier. In Nepomuk this UUID is guaranteed to be unique on one system. A resource with the same UUID can exist as completely different resources on different systems.

== Doesn't Nepomuk need the location of the Resourcce? ==

Yes, we do! But just like "A rose by any other name would smell as sweet", the location of a resource is independent of its name. Its name ( UUID ) never changes. If the resource has a location then the location is stored as a URL using the property nie:url.

Not all resource have a location. Nepomuk is used to store abstract stuff like Contacts, Events and People, they do not have a location. Concrete stuff like pictures, videos and files do have locations.

== Tell me more about these URLS ==

A URL is like the physical representation of an object. In Nepomuk all URLs must have a proper scheme that KDE supports. Example `smb:/192.168.1.50/Multimedia/` or akonadi:?item=21. These all are stored in the nie:url property of the resource.

== You're lying! I see resource URIs like 'akonadi:?item=21' ==

This URI nomenclature has been decided in June 2011, we're still in the process of porting all existing URIs to URLS. We want there to be a clear distinction.
Well that's cause we're still in the process of porting

== Why go through all this trouble? ==

The rationale in having random UUID based URIs in Nepomuk is two fold. One, we have a guarantee that the URI is random, and means nothing. This is important when restoring backups or synchronization or when sharing resource among different systems. If you're restoring a resource and its URI already exists, no problem, just generate another one. It's not like they have any concrete meaning. The URL however does have a concrete meaning, and that we need to respect.

The second reason is that all URIs follow one naming convention? ( vHanda: What was the second reason? )

== What about the Semantic Web? ==

Nepomuk is the Semantic Desktop, while we acknowledge the fact of the Semantic Web, we currently do not go out of our way to support it. It's a messy situation, and we don't have a solution right now. If you have any ideas on how we can have better interoperability with the Semantic Web, then please let us on the Nepomuk Mailing List.

@@ Line 2: / Line 2: @@
 <translate>
-== Scope of this page ==
+== Scope of this page == <!--T:1-->
 This document describes in depth how URIs are stored in '''Nepomuk''', and their significance.
-==  What is a URI? ==
+==  What is a URI? == <!--T:3-->
 A URI or ''Uniform Resource Identifier'' is a string of characters used to identify or locate a resource. URIs can be of two types, or both -
 * URN - Uniform Resources Names
 * URL - Uniform Resource Locator.
 A URN is a unique way of identifying a resource. It does not provide any information about how the resource can be found> Rather it provides a way to uniquely identify a resource. For example - <tt>urn:isbn:037584614X</tt>. This urn tells you nothing about how to find the book that it just mentions a unique identifier. You can take the ISBN and somehow locate [http://www.amazon.com/Nick-Norahs-Infinite-Playlist-Rachel/dp/037584614X the book]
 A URL, in contrast, provides a way to access the resource. For example - <tt>file:///home/user/file</tt>. This url clearly dictates that the <tt>file</tt> protocol should be used along with the path <tt>/home/user/file</tt>. It does not give a unique way of identifying the resource. It just provides one way to access the resource.
-== So what does Nepomuk use? ==
+== So what does Nepomuk use? == <!--T:7-->
 Nepomuk URIs are in a way URNs, though unlike conventional URNs which provide a globally unique way of identifying a resource, they provide a unique way of identifying a resource '''on one machine'''. This is important - '''Nepomuk''' URIs are NOT machine independent. The same resource can have different URIs on different systems. This is because all URIs in '''Nepomuk''' are randomly generated. They follow a pattern -
 <blockquote>nepomuk:/res/uuid</blockquote>
 UUID stands for a ''Universally Unique Identifier''. In Nepomuk this UUID is guaranteed to be unique on one system. A resource with the same UUID can exist as completely different resources on different systems.
-== Doesn't Nepomuk need the location of the Resource? ==
+== Doesn't Nepomuk need the location of the Resource? == <!--T:11-->
 Yes, we do! But the location of a resource is independent of its name. Its name ( UUID ) never changes. If the resource has a location then the location is stored as a URL using the property [http://oscaf.sourceforge.net/nie.html#nie:url <code>nie:url</code>].
 Not all resources have a location. '''Nepomuk''' is also used to store abstract stuff like Contacts, Events and People, they do not have a location. Concrete stuff like pictures, videos and files do have locations.
-== Tell me more about these URLS ==
+== Tell me more about these URLS == <!--T:14-->
 A URL is like the physical representation of an object. In '''Nepomuk''' all URLs must have a proper scheme that KDE supports. Example <tt>smb:/192.168.1.50/Multimedia/</tt> or <tt>akonadi:?item=21</tt>. These all are stored in the nie:url property of the resource.
-== You're lying! I see resource URIs like <tt>akonadi:?item=21</tt> ==
+== You're lying! I see resource URIs like <tt>akonadi:?item=21</tt> == <!--T:16-->
 This URI nomenclature was decided in June 2011. We're still in the process of making sure all URIs follow our naming convention. With KDE 4.10, there will be a data migration client which will make sure the old data is converted to this new uri format.
-== Why go through all this trouble? ==
+== Why go through all this trouble? == <!--T:18-->
 The rationale in having random UUID based URIs in '''Nepomuk''' is two-fold. One, we have a guarantee that the URI is random, and means nothing. This is important when restoring backups or synchronization or when sharing resource among different systems. If you're restoring a resource and its URI already exists, no problem, just generate another one. It's not like they have any concrete meaning. The URL however does have a concrete meaning, and that we need to respect.
 The second reason is that all URIs follow one naming convention.
-== What about the Semantic Web? ==
+== What about the Semantic Web? == <!--T:21-->
 '''Nepomuk''' is the Semantic Desktop, while we acknowledge the existence of the Semantic Web, we currently do not go out of our way to support it. It's a messy situation, and we don't have a solution right now. If you have any ideas on how we can have better interoperability with the Semantic Web, then please come talk to us.
 [[Category:Documentation]]
 [[Category:Development]]
 [[Category:Tutorials]]
 </translate>

@@ Line 1: / Line 1: @@
-This document describes in depth how URIs are stored in Nepomuk, and their significance.
+<languages />
-= What is a URI? =
+== Scope of this page ==
-A URI or Uniform Resource Identifier is a string of characters used to identify or locate a resource. URIs can be of two types, or both -
+This document describes in depth how URIs are stored in '''Nepomuk''', and their significance.
 * URN - Uniform Resources Names
 * URL - Uniform Resource Locator.
@@ Line 11: / Line 16: @@
 A URL, in contrast, provides a way to access the resource. For example - <tt>file:///home/user/file</tt>. This url clearly dictates that the <tt>file</tt> protocol should be used along with the path <tt>/home/user/file</tt>. It does not give a unique way of identifying the resource. It just provides one way to access the resource.
-= So what does Nepomuk use? =
+== So what does Nepomuk use? ==
-Nepomuk URIs are in a way URNs, though unlike conventional URNs which provide a globally unique way of identifying a resource, they provide a unique way of identifying a resource '''on one machine'''. This is important - Nepomuk URIs are NOT machine independent. The same resource can have different URIs on different systems. This is because all URIs in Nepomuk are randomly generated. They follow a pattern -
+Nepomuk URIs are in a way URNs, though unlike conventional URNs which provide a globally unique way of identifying a resource, they provide a unique way of identifying a resource '''on one machine'''. This is important - '''Nepomuk''' URIs are NOT machine independent. The same resource can have different URIs on different systems. This is because all URIs in '''Nepomuk''' are randomly generated. They follow a pattern -
 <blockquote>nepomuk:/res/uuid</blockquote>
@@ Line 19: / Line 24: @@
 UUID stands for a ''Universally Unique Identifier''. In Nepomuk this UUID is guaranteed to be unique on one system. A resource with the same UUID can exist as completely different resources on different systems.
-= Doesn't Nepomuk need the location of the Resourcce? =
+== Doesn't Nepomuk need the location of the Resource? ==
 Yes, we do! But the location of a resource is independent of its name. Its name ( UUID ) never changes. If the resource has a location then the location is stored as a URL using the property [http://oscaf.sourceforge.net/nie.html#nie:url <code>nie:url</code>].
-Not all resource have a location. Nepomuk is also used to store abstract stuff like Contacts, Events and People, they do not have a location. Concrete stuff like pictures, videos and files do have locations.
+Not all resources have a location. '''Nepomuk''' is also used to store abstract stuff like Contacts, Events and People, they do not have a location. Concrete stuff like pictures, videos and files do have locations.
-= Tell me more about these URLS =
+== Tell me more about these URLS ==
-A URL is like the physical representation of an object. In Nepomuk all URLs must have a proper scheme that KDE supports. Example <tt>smb:/192.168.1.50/Multimedia/</tt> or <tt>akonadi:?item=21</tt>. These all are stored in the nie:url property of the resource.
+A URL is like the physical representation of an object. In '''Nepomuk''' all URLs must have a proper scheme that KDE supports. Example <tt>smb:/192.168.1.50/Multimedia/</tt> or <tt>akonadi:?item=21</tt>. These all are stored in the nie:url property of the resource.
-= You're lying! I see resource URIs like <tt>akonadi:?item=21</tt> =
+== You're lying! I see resource URIs like <tt>akonadi:?item=21</tt> ==
 This URI nomenclature was decided in June 2011. We're still in the process of making sure all URIs follow our naming convention. With KDE 4.10, there will be a data migration client which will make sure the old data is converted to this new uri format.
-= Why go through all this trouble? =
+== Why go through all this trouble? ==
-The rationale in having random UUID based URIs in Nepomuk is two fold. One, we have a guarantee that the URI is random, and means nothing. This is important when restoring backups or synchronization or when sharing resource among different systems. If you're restoring a resource and its URI already exists, no problem, just generate another one. It's not like they have any concrete meaning. The URL however does have a concrete meaning, and that we need to respect.
+The rationale in having random UUID based URIs in '''Nepomuk''' is two-fold. One, we have a guarantee that the URI is random, and means nothing. This is important when restoring backups or synchronization or when sharing resource among different systems. If you're restoring a resource and its URI already exists, no problem, just generate another one. It's not like they have any concrete meaning. The URL however does have a concrete meaning, and that we need to respect.
 The second reason is that all URIs follow one naming convention.
-= What about the Semantic Web? =
+== What about the Semantic Web? ==
-Nepomuk is the Semantic Desktop, while we acknowledge the existence of the Semantic Web, we currently do not go out of our way to support it. It's a messy situation, and we don't have a solution right now. If you have any ideas on how we can have better interoperability with the Semantic Web, then please come talk to us.
+[[Category:Documentation]]

@@ Line 3: / Line 3: @@
 = What is a URI? =
-A URI or Uniform Resource Identifier is a string of characters used to identify or locate a resource. URIs can be of two types, or both - URNs and URLs. A URN, Uniform Resource Name, is a unique way of identifying a resource. It does not provide any information about how the resource can be found, example - <tt>urn:isbn:0374193681</tt>. A URL, Uniform Resource Locator, provides a way to access the resource. Example - <tt>file:///home/user/file</tt>. This url clearly dictates that the 'file' protocol should be used along with the path <tt>/home/user/file</tt>. It does not give a unique way of identifying the resource. It just provides one way to access the resource.
+A URI or Uniform Resource Identifier is a string of characters used to identify or locate a resource. URIs can be of two types, or both -
-= So what does Nepomuk use? =
+A URN is a unique way of identifying a resource. It does not provide any information about how the resource can be found> Rather it provides a way to uniquely identify a resource. For example - <tt>urn:isbn:037584614X</tt>. This urn tells you nothing about how to find the book that it just mentions a unique identifier. You can take the ISBN and somehow locate [http://www.amazon.com/Nick-Norahs-Infinite-Playlist-Rachel/dp/037584614X the book]
-Nepomuk URIs are in a way URNs, though unlike conventional URNs which provide a globally unique way of identifying a resource, they provide a unique way of identifying a resource '''on one machine'''. This is important - Nepomuk URIs are NOT machine independent. The same resource can have different URIs on different systems. This is because all URIs in Nepomuk are randomly generated. They follow a pattern -
+A URL, in contrast, provides a way to access the resource. For example - <tt>file:///home/user/file</tt>. This url clearly dictates that the <tt>file</tt> protocol should be used along with the path <tt>/home/user/file</tt>. It does not give a unique way of identifying the resource. It just provides one way to access the resource.
-<blockquote>`nepomuk:/TYPE/uuid`</blockquote>
+= So what does Nepomuk use? =
-where -
+Nepomuk URIs are in a way URNs, though unlike conventional URNs which provide a globally unique way of identifying a resource, they provide a unique way of identifying a resource '''on one machine'''. This is important - Nepomuk URIs are NOT machine independent. The same resource can have different URIs on different systems. This is because all URIs in Nepomuk are randomly generated. They follow a pattern -
-TYPE is either '''res''' or '''ctx'''. ''res'' is an abbreviation for Resource, while ''ctx'' is an abbreviation for Context or Graph.
+<blockquote>nepomuk:/res/uuid</blockquote>
 UUID stands for a ''Universally Unique Identifier''. In Nepomuk this UUID is guaranteed to be unique on one system. A resource with the same UUID can exist as completely different resources on different systems.
@@ Line 19: / Line 21: @@
 = Doesn't Nepomuk need the location of the Resourcce? =
-Yes, we do! But just like "A rose by any other name would smell as sweet", the location of a resource is independent of its name. Its name ( UUID ) never changes. If the resource has a location then the location is stored as a URL using the property nie:url.
+Yes, we do! But the location of a resource is independent of its name. Its name ( UUID ) never changes. If the resource has a location then the location is stored as a URL using the property [http://oscaf.sourceforge.net/nie.html#nie:url <code>nie:url</code>].
-Not all resource have a location. Nepomuk is used to store abstract stuff like Contacts, Events and People, they do not have a location. Concrete stuff like pictures, videos and files do have locations.
+Not all resource have a location. Nepomuk is also used to store abstract stuff like Contacts, Events and People, they do not have a location. Concrete stuff like pictures, videos and files do have locations.
 = Tell me more about these URLS =
@@ Line 29: / Line 31: @@
 = You're lying! I see resource URIs like <tt>akonadi:?item=21</tt> =
-This URI nomenclature was decided in June 2011. We're still in the process of making sure all URIs follow our naming convention. Hopefully we can automate this process.
+This URI nomenclature was decided in June 2011. We're still in the process of making sure all URIs follow our naming convention. With KDE 4.10, there will be a data migration client which will make sure the old data is converted to this new uri format.
 = Why go through all this trouble? =
@@ Line 39: / Line 41: @@
 = What about the Semantic Web? =
-Nepomuk is the Semantic Desktop, while we acknowledge the existence of the Semantic Web, we currently do not go out of our way to support it. It's a messy situation, and we don't have a solution right now. If you have any ideas on how we can have better interoperability with the Semantic Web, then please let us on the Nepomuk Mailing List.
+Nepomuk is the Semantic Desktop, while we acknowledge the existence of the Semantic Web, we currently do not go out of our way to support it. It's a messy situation, and we don't have a solution right now. If you have any ideas on how we can have better interoperability with the Semantic Web, then please come talk to us.

@@ Line 5: / Line 5: @@
 == What is a URI? ==
-A URI or Uniform Resource Identifier is a string of characters used to identify or locate a resource. URIs can be of two types, or both - URNs and URLs. A URN, Uniform Resource Name, is a unique way of identifying a resource. It does not provide any information about how the resource can be found, example - urn:isbn:0374193681. A URL, Uniform Resource Locator, provides a way to access the resource. Example - file:///home/user/file. This url clearly dictates that the 'file' protocol should be used along with the path '/home/user/file'. It does not give a unique way of identifying the resource. It just provides one way to access the resource.
+A URI or Uniform Resource Identifier is a string of characters used to identify or locate a resource. URIs can be of two types, or both - URNs and URLs. A URN, Uniform Resource Name, is a unique way of identifying a resource. It does not provide any information about how the resource can be found, example - <tt>urn:isbn:0374193681</tt>. A URL, Uniform Resource Locator, provides a way to access the resource. Example - <tt>file:///home/user/file</tt>. This url clearly dictates that the 'file' protocol should be used along with the path <tt>/home/user/file</tt>. It does not give a unique way of identifying the resource. It just provides one way to access the resource.
 == So what does Nepomuk use? ==
@@ Line 17: / Line 17: @@
 TYPE is either '''res''' or '''ctx'''. ''res'' is an abbreviation for Resource, while ''ctx'' is an abbreviation for Context or Graph.
-UUID stands for a Universally Unique Identifier. In Nepomuk this UUID is guaranteed to be unique on one system. A resource with the same UUID can exist as completely different resources on different systems.
+UUID stands for a ''Universally Unique Identifier''. In Nepomuk this UUID is guaranteed to be unique on one system. A resource with the same UUID can exist as completely different resources on different systems.
 == Doesn't Nepomuk need the location of the Resourcce? ==
@@ Line 27: / Line 27: @@
 == Tell me more about these URLS ==
-A URL is like the physical representation of an object. In Nepomuk all URLs must have a proper scheme that KDE supports. Example `smb:/192.168.1.50/Multimedia/` or akonadi:?item=21. These all are stored in the nie:url property of the resource.
+A URL is like the physical representation of an object. In Nepomuk all URLs must have a proper scheme that KDE supports. Example <tt>smb:/192.168.1.50/Multimedia/</tt> or <tt>akonadi:?item=21</tt>. These all are stored in the nie:url property of the resource.
-== You're lying! I see resource URIs like 'akonadi:?item=21' ==
+== You're lying! I see resource URIs like <tt>akonadi:?item=21</tt> ==
 This URI nomenclature was decided in June 2011. We're still in the process of making sure all URIs follow our naming convention. Hopefully we can automate this process.

← Older revision		Revision as of 14:23, 14 July 2011
Line 41:		Line 41:
	== What about the Semantic Web? ==		== What about the Semantic Web? ==

−	Nepomuk is the Semantic Desktop, while we acknowledge the ~~fact~~ of the Semantic Web, we currently do not go out of our way to support it. It's a messy situation, and we don't have a solution right now. If you have any ideas on how we can have better interoperability with the Semantic Web, then please let us on the Nepomuk Mailing List.	+	Nepomuk is the Semantic Desktop, while we acknowledge the existence of the Semantic Web, we currently do not go out of our way to support it. It's a messy situation, and we don't have a solution right now. If you have any ideas on how we can have better interoperability with the Semantic Web, then please let us on the Nepomuk Mailing List.