Re: [Tracker] The quadruple, team conversations on IRC

On Fri, 2009-07-31 at 14:07 +0300, Ivan Frade wrote:
About the quad store,

On Fri, Jul 31, 2009 at 1:17 PM, Martyn Russell <martyn lanedo com>
        On 29/07/09 13:53, Philip Van Hoof wrote:
                o. We want to start having a quadruple alongside the
                decomposed sqlite
                   o. Such a quadruple will allow us to implement
                   o. Such a quadruple will allow us to implement
                named graph support

        I think we need some real world examples here. At least from
        what I have seen with 0.6. the problems come when we want to
        store data like LastPlayed or Tags and from multiple
        locations. For example, if there are 2 media players or
        perhaps a file can be used in a video player AND a music
        player and they both want to store LastPlayed independently or
        have Tags uniquely set by themselves not shown between all
        Are there any others good examples I have missed here?

Named graph means to add a fourth element to the "triplets" (then are
not triplets anymore, i guess). We can use that forth parameter for a
lot of things or for none:

* we can use it to mark the "source" of the information (hard-disk,
removable-device, flickr, facebook), 
* we can use it for backup... (how? where is the logic to decide if
something is ready for backup?... )
* we can use it for sync (again, how? a pseudo code from the
application point of view)
* we can use it to differentiate the embedded and not embedded

 BUT we cannot use it for the 4 things at the same time, unless we
have the same triplet 4 times... 

It is possible if you use a different graph URI for each SPARQL update
(=origin), and then describe that graph with an arbitrary amount of
statements (as in your list). However, it might increase the amount of
data quite a bit if used intensively. I don't know whether the overhead
is justified.


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