[Nepomuk] Refactoring for Soprano 3

Max Hofer mh182 at gmx.net
Tue Oct 13 21:20:12 CEST 2009

On Tuesday 13 October 2009 16:57:58 Sebastian Trüg wrote:
> Hello,
> Soprano 2 IMHO has a nice design. Backend, Model, and FilterModel suited my
> needs very well and were nice to use. But now it slowly reaches its limits.
> With Virtuoso the introduction of transactions become very important. I
>  tried to stack them on top of Model as you can see in the experimental
>  branch[1] but the resulting design is flawed and cannot be any different
>  since we need to stay binary compatible for KDE.
> Thus, it is time for a redesign and also time for you to state your needs
>  and ideas.
> Attached you find a preliminary design in the form of a crude UML diagram.
>  It is based on the sesame2 idea of Respository vs. RespositoryConnection.
Is there a general overview (description) how sesame2 and the other backends 
work in the overall concept of Nepomuk and Soprano?

Before I can give my 2 cents I needs to grasp the overall concept ... which 
may take some weeks.

> A few words of explanation:
> - Model is split into two classes Repository and RepositoryConnection.
>   Each RespositoryConnection represents its own transaction object, i.e.
>   can perform multiple transactions.
If you say "perform multiple transactions" do you mean those transactions are 
performed sequentially per connection? Or can they also be processed in 

> - A Repository can create an arbitrary number of RespositoryConnection
>   objects.
> - Backend is now RepositoryFactoy (better name welcome). It is used to
>   create StorageRepositories which replace StorageModel and have settings
>   like storage dir and the like.
> - FilterRepository and FilterRepositoryConnection replace the current
>   FilterModel.
Newbie question: on which objects are filter applied? The result of the query?

>   A FilterRepository would need to create its own connections which carry
>   as a member a parent connection created by the parent Repository.
> This is the basis I would like to start the discussion from.
> Another issue is inference which I would like to integrate deeper into
> Soprano. The straight forward design would be to add a flags parameter to
> method like query() and listStatements() which can for example be
> EnableInference.

More information about the Nepomuk mailing list