On 1/21/07, Damaris Fuentes <dfl_maradentro / yahoo.es> wrote:

> Well, it's just I think my questions are quite silly for the mailing
> list, which is very advanced, as far as what I've seen in it... :(

I don't think that should discourage you from posting your question(s)
there. If anyone's an expert on ActiveRDF it should be them!

> My questions are the following:
> - ActiveRDF can work with Jena, as FAQ[1] says. However, there is no
> adapter for Jena [2]. Furthermore, Jena is not a database by itself,
> it's a framework with no DB (DB can be then MySQL, Oracle, etc.). I
> would like to know more about this cause my application will have to do
> inferences.

Like you, I haven't seen an adapter for Jena in the official release
of ActiveRDF. I did a Google search of the ActiveRDF mailing list
(using the search string "jena site:lists.deri.org") and came up with
this hit:

    http://lists.deri.org/pipermail/activerdf/2006-November/000144.html

Based on this (the announcement of ActiveRDF 1.0, from last November)
it sounds like the Jena adapter is still under development. Perhaps
it's in their source code repository if you check that out (I haven't
done that).

You're right of course that Jena isn't a database per se. I'm
*guessing* that the ActiveRDF adapter for Jena is analogous to the
adapter for Redland (which isn't a database either). The adapter for
Redland is a wrapper around a Redland model, which could be backed by
either a database or in-memory store.

> - There is no adapter for YARS if I wanted to use it.

See previous link, which also claims that a YARS adapter is "under development".

> - If my adapter is "rdflite" and I load data from a file, has my file to
> be in N3 format?

I've only used the Redland adapter so far, but I found that by default
it was looking for N3 formatted triples. I found, however, that by
adding a second argument in the call to load that I could load an
RDF/XML formatted file, e.g.

    store = ConnectionPool.add_data_source(:type => :redland)
    store.load("example.rdf", "rdfxml")

I don't know if this will work with the rdflite adapter, though.

> - I'm doing the examples for writing with RDFlite. However, I haven't
> installed RDFLite yet so, is there information there on how to install
> RDFLite, or SQLite3, and how my connection should be established? I
> would like to test all of this with RDFLite before changing to something
> like Jena.

This page:

    http://wiki.activerdf.org/GettingStartedGuide

has some instructions about installing the RDFLite adapter, which
appears to depend on sqlite3, the sqlite3 gem, and ferret. It looks
like there are also some instructions there about how to establish a
connection once you've got it all installed.

Hope this helps,

Lyle

P.S. I would strongly recommend following up on the ActiveRDF mailing
list. They could for example tell you more about the current
development status of the Jena and YARS adapters.