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Re: A Proposed 5th Rule/Principle for Linked Data

June 1, 2010

Joining the conversation with Matthew Rowe, Alex Passant, Olaf Hartig, Bernhard Schandl and Hannes Mühleisen.

Matthew’s post proposes:
“So, if you have a URI which describes a resource that has fixed data (e.g. the DBPedia URI for the Battle of Waterloo) then pushing data such a URI should not be allowed. There may be a case where a resource description needs to be updated (e.g. my data.dcs URI), however the party who wishes to update the URI must be authorised as being permitted to do so.Moving towards pushing data would not only reduce the computation forced on dataset generation processes, but would also produce a writable web of data, something which would querying of up-to-date resource descriptions.”

Although I’m not sure about reducing computation (many people could be trying to update resources at the same time all the time), I surely see a lot of value in a writable web of data. I envision a network of trusted Linked Data servers where one party can digitally sign a SPARQL UPDATE and send the update to another trusted party. The server receiving the update could then check that the command comes from a ‘friend’ and decide to accept it. (Update: as Matthew also noted,) Allowing writes without authentication would generate a structured spam nightmare!

One point with which I disagree is Matthew’s comment that there are fixed data about which no push should be allowed. In our paper at WebSci’2010, we took a stab at studying types of relationships with regard to how “fixed” they may be, and we call attention to the fact that dynamic data exist and are very valuable. One could want to add, for example, that the Battle of Waterloo is being staged in a play somewhere. This is one example of “associative” relationship that, although not trying to define the Battle of Waterloo, potentially has significant value for users/agents visiting that resource. In that work we dynamically extracted very simple relationships from Twitter and allowed users to save the ones they thought were interesting. I advocate that pushes about “fixed data” should not only be allowed, but encouraged if we want to increase value in the Linked Open Data cloud.

Our project page is here:
And our paper at WebSci2010:
Dynamic Associative Relationships on the Linked Open Data Web

  1. I think nobody seriously questions that certain data sets must not be modified without authentication, or must not be modified at all. Matthew also mentioned the need for authentication in his blog post.

  2. Hi Bernhard,
    sorry for the lack of eloquence. I updated the post to reflect my recognition that he mentions authentication. I just wanted to allude to a possible way to implement such authenticated updates, and be louder than he was (with the risk of being annoying) about the need for it. 🙂

    The point about “certain datasets must not be modified at all” though, I’m not sure. Matthew says: “there will be fixed data and changeable data. I think that the former should not change.” So he does mention that some (sub)sets should not be touched.

    Maybe what we need to do is to organize the discussion to figure out what types of push can be made to a store, and how we should authorize each type. Changes to a rigid definition [1] (PATCH) are inherently different from just updates (HTTP UPDATE) to some anti-rigid or non-rigid property, and should be handled differently.

    What do you think?


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