DPLA is working on moving to a more RDF-aware stack, including Marmotta[1]
as a triplestore, Linked Data Platform server, and Linked Data cache layer.

You can check out our data model[2], which we use as a common format for
special collections/archives/museum metadata aggregated from our partners.
Marmotta gives us RDF persistence with graph query via SPARQL, and a REST
interface via LDP[3].  Most/all of our actual interactions with the data
are mediated by ActiveTriples[4], an ORM-like interface to RDF resources.
From there, it's just like any other application, with the benefits (and
pitfalls) offered by a graph model, Open World, URIs, etc... becoming
tangible from time to time.

[1] http://marmotta.apache.org/
[2] http://dp.la/info/wp-content/uploads/2013/04/DPLA-MAP-V3.1-2.pdf
[3] http://www.w3.org/TR/ldp/
[4] https://github.com/ActiveTriples/ActiveTriples

On Fri, Dec 19, 2014 at 7:32 AM, Forrest, Stuart <[log in to unmask]> wrote:

> Thanks Jeff
>
> Interesting concept, can you give me any examples of their usage, what
> kinds of data etc.?
>
> Thanks
>
>
> ================================================================================
> Stuart Forrest PhD
> Library Systems Specialist
> Beaufort County Library
> 843 255 6450
> [log in to unmask]
>
> http://www.beaufortcountylibrary.org
>
> For Leisure, For Learning, For Life
>
>
>
>
> -----Original Message-----
> From: Code for Libraries [mailto:[log in to unmask]] On Behalf Of
> Mixter,Jeff
> Sent: Friday, December 19, 2014 10:20 AM
> To: [log in to unmask]
> Subject: Re: [CODE4LIB] rdf triplestores
>
> A triplestore is basically a database backend for RDF triples. The major
> benefit is that it allows for SPARQL querying. You could imagine a
> triplestore as being the same thing as a relational database that can be
> queried with SQL.
>
> The drawback that I have run into is that unless you have unlimited
> hardware, triplestores can run into scaling problems (when you are looking
> at hundreds of millions or billions of triples). This is a problem when you
> want to search for data. For searching I use a hybrid Elasticsearch (i.e.
> Lucene) index for the string literals and the go out to the triplestore to
> query for the data.
>
> If you are looking to use a triplestore it is important to distinguish
> between search and query.
>
> Triplestore are really good for query but not so good for search. The
> basic problem with search is that is it mostly string based and this
> requires a regular expression query in SPARQL which is expensive from a
> hardware perspective.
>
> There are a few triple stores that use a hybrid model. In particular Jena
> Fuseki (http://jena.apache.org/documentation/query/text-query.html)
>
> Thanks,
>
> Jeff Mixter
> Research Support Specialist
> OCLC Research
> 614-761-5159
> [log in to unmask]
>
> ________________________________________
> From: Code for Libraries <[log in to unmask]> on behalf of Forrest,
> Stuart <[log in to unmask]>
> Sent: Friday, December 19, 2014 10:00 AM
> To: [log in to unmask]
> Subject: Re: [CODE4LIB] rdf triplestores
>
> Hi All
>
> My question is what do you guys use triplestores for?
>
> Thanks
> Stuart
>
>
>
> ================================================================================
> Stuart Forrest PhD
> Library Systems Specialist
> Beaufort County Library
> 843 255 6450
> [log in to unmask]
>
> http://www.beaufortcountylibrary.org
>
> For Leisure, For Learning, For Life
>
>
>
> -----Original Message-----
> From: Code for Libraries [mailto:[log in to unmask]] On Behalf Of
> Stefano Bargioni
> Sent: Monday, November 11, 2013 8:53 AM
> To: [log in to unmask]
> Subject: Re: [CODE4LIB] rdf triplestores
>
> My +1 for Joseki.
> sb
>
> On 11/nov/2013, at 06.12, Eric Lease Morgan wrote:
>
> > What is your favorite RDF triplestore?
> >
> > I am able to convert numerous library-related metadata formats into
> RDF/XML. In a minimal way, I can then contribute to the Semantic Web by
> simply putting the resulting files on an HTTP file system. But if I were to
> import my RDF/XML into a triplestore, then I could do a lot more. Jena
> seems like a good option. So does Openlink Virtuoso.
> >
> > What experience do y'all have with these tools, and do you know how to
> import RDF/XML into them?
> >
> > --
> > Eric Lease Morgan
> >
>