SPARQL Protocol for RDF

https://www.w3.org/TR/rdf-sparql-protocol/

by mindcrime • 9 years ago

43 52 9 years ago

rspeer7• 9 years ago

SPARQL is what happens when you try to define an API for doing everything, from abstract principles, and end up with an API that does nothing.

It wraps your database in a worse database with a worse query language. It makes simple queries into kilobyte-long GET query strings that get morasses of XML-namespace nonsense as a response, or more likely, a server timeout.

While the W3C was screwing around with SPARQL, everyone else came up with JSON-based REST APIs. They work well. Not even the core W3C people use SPARQL anymore.

slaymaker1907• 9 years ago

You just keep thinking that until you see the god awful mess of REST apis that happens when you need to make an endpoint for every single slightly different query.

linkmotif3• 9 years ago

Yeah REST... it's for the truly patient and perseverant. Not to mention the pedantic. "REST principles"—heh. Also: JSON :(.

Thank God GraphQL is changing this paradigm and has useable and even powerful clients already. Only bad thing about GraphQL is that it targets JSON but at least it's typed and schematic.

But I guess we all benefited from REST, in the sense that it killed the whole 900-page XML book scene which was maybe the worst thing ever.

rspeer7• 9 years ago

Yeah, that's kind of how APIs have to work. It turns out it's not feasible or desirable to just let arbitrary people make arbitrary queries. SPARQL doesn't make it any more feasible, it just ignores feasibility.

lemmsjid2• 9 years ago

I'm confused. Isn't SPARQL a query language for RDF? I've used SPARQL extensively against triple stores. It's quite handy and pretty easy to pick up once you grok how RDF is structured. I wouldn't even compare it with the concept of RESTful APIs--they're attacking two different problems.

rspeer7• 9 years ago

What were your triple stores running on? A database, right?

Do your SPARQL queries turn into anything within orders of magnitude of an efficiently indexed SQL query when they get to the database?

hcarvalhoalves• 9 years ago

Comparing SPARQL to REST doesn't make sense. RDF is a different beast.

rspeer7• 9 years ago

The linked article is describing a world where you encode SPARQL in HTTP query parameters and get back RDF+XML. It really is attempting to be an API for querying everything, but querying nothing well.

You can write reasonable REST APIs for RDF. You can even formalize it with JSON-LD if you care to.

mindcrime5• 9 years ago

We use SPARQL heavily. YMMV. shrug

dragonwriter5• 9 years ago

It wraps your database in a worse database with a worse query language.

SPARQL doesn't necessarily wrap a database with a different underlying query language. And it's a much better query language than SQL for RDF data.

It makes simple queries into kilobyte-long GET query strings

Don't do that. I mean, seriously, the protocol supports queries with GET, but it also supports t o different mechanisms for querying over POST.

that get morasses of XML-namespace nonsense as a response

SPARQL does not mandate XML responses (for graph responses, it doesn't specify a non-XML serialization, but still on requires RDF/XML or a semantically equivalent structure. For other responses, there are defined JASON, XML, and CSV/TSV formats.

While the W3C was screwing around with SPARQL, everyone else came up with JSON-based REST APIs.

SPARQL's defined API is more REST than most of those.

They work well.

Not for the purpose SPARQL is aimed at, which is—admittedly—not a particularly common use case, and certainly not what your typical web service needs.

mfrager• 9 years ago

SPARQL is not an API framework as much as it is a query language. Many powerful graph databases are queried via SPARQL.

rspeer7• 9 years ago

As a feature to put on a checklist, not as the way they expect you to use them. Powerful graph databases generally have to come up with their own query languages.

ghukill• 9 years ago

Are there queries that SPARQL can perform over a triplestore that cannot be done with SQL over normalized data? Perhaps not.

But data normalization to that end is a moving target, while a bag of subject-predicate-object statements are quite doable. This, I believe, is a uniquely powerful characteristic of linked data / graph query languages and protocols.

To that end, agree with the comment above that GraphQL is mighty exciting.

linkmotif3• 9 years ago

GraphQL, though, is a bit of a lie nomenclature-wise. As I've experienced it, it's got nothing much to do with graphs, at least not in the sense that SPARQL deals with triples that form a graph. In this department I am really interested in TinkerPop [0].

I would love, some day, to spend some more time with triple stores, RDF and semantic technologies.

[0] http://tinkerpop.apache.org/docs/current/reference/

handojin• 9 years ago

You might really enjoy datomic (www.datomic.com). Everything is stored as entity attribute value time and you query with a dialect of datalog. You can check out www.learndatalogtoday.org to get a flavor.

barakm• 9 years ago

+1 Insightful. In fact, there's research toward showing the two are equivalent in possibility space of what can be represented/queried (https://arxiv.org/abs/1102.1889)

But yes, linked data and graphs are super powerful once the data is triplified. Suddenly you have an abstraction above the contents of your data into the 'shape' of your data.

SPARQL and RDF aren't going away, but they're the academic thing that I and others are trying to make useful. GraphQL is scratching the surface, but it's super exciting that it's scratching at all, imo.

(Disclosure: Founded CayleyGraph, supporting the open source https://github.com/cayleygraph/cayley, which I maintain and mostly wrote)

miguelrochefort• 9 years ago

Nothing makes me happier than seeing the semantic web hit the front page.

Too bad most people don't understand it.

mindcrime5• 9 years ago

Same here. Honestly though, I'm surprised. I submitted this even though it's kinda old, because I was reading up on federated SPARQL queries, and had a random thought that somebody might find it interesting. I didn't actually expect any significant number of upvotes, or for this to make the front-page.

My feeling is, the Semantic Web vision is still growing and still permeating it's way through things. I think it's taken longer than probably anybody expected, but it's an ambitious-as-fuck-all idea too, so that should hardly be surprising.

The thing is, in this fad-driven industry, once something slips off the hype wagon, and isn't "cool" or "sexy" anymore, it's something of a struggle to get people interested. Everybody is all "ooooooh, shiny!" and off to chase the javascript framework du jour.

phlakaton• 9 years ago

Count me as one of them, though I'm more conversant about it than some. Let me ask then: what would you have people understand?

dnt404-1• 9 years ago

Anybody can share some light on companies that uses semantic web technologies? Currently at university have a semantic web class but I am finding it difficult where the use case are to create value for business or startup.

tannhaeuser2• 9 years ago

Facebook Open Graph crawlers use RDF in HTML head-meta elements conveying data about authors of web pages.

Similarly, Google Corporate Contacts extracts RDF from web pages (but can also use JSON microdata).

W3C's newly published open social standard is based on RDF (as JSON-LD) I believe.

RDF and SPARQL has lots of uses in libraries and bibliographic apps such as citation managers, as well as in publication of open data, in particular medical and bio informatics data.

Dublin Core (as RDF) is frequently used for standard document metadata, for example in PDF.

hsivonen• 9 years ago

Does Facebook now actually do RDFa-compliant processing for OGP? Back when OGP was introduced they didn't. https://lists.w3.org/Archives/Public/www-archive/2011Apr/006...

Vinnl2• 9 years ago

I believe Schema.org uses (/can use?) linked data that e.g. Google can again use to provide more relevant information about your content: https://developers.google.com/schemas/

fxaguessy• 9 years ago

Yes, for example at Wallix, we created awless.io a CLI for AWS, that uses RDF (https://github.com/wallix/triplestore) to model cloud data. So far this linked data has help us since it is loosely coupled and has graph-like properties.

anon12532• 9 years ago

We use quite a bit of SPARQL to reason over medical ontologies. It's not exactly "semantic web", but ontological knowledge (such as the Gene Database, UMLS, etc) are naturally serialized in graphs, which makes them an excellent fit for RDF triplestores, hence SPARQL. We regularly query millions of concepts with billions of relations in milliseconds. True, RDF under the hood is just a EAV model, but thinking about the identity between triples, graphs, and logic programming makes a lot of sense for us.

https://joelkuiper.eu/semantic-web

jerven• 9 years ago

I love SPARQL, although I often say it causes problems for developers but solves problems for organizations.

I know I am not in the average developer sphere, but working as a data provider to the wider public (ok scientific public) SPARQL is fantastic. First is that classic rest+json give data but do not allow analytics. Second is that SPARQL has federation. While CPU time wise it is inefficient for scientists its saves them months trying to get a local copy of the db setup.

SPARQL implementations are reasonably efficient and certainly do not need to be less efficient than SQL stores (even if they often are). However, as it is a query language not an implementation it can behave completely different. i.e. it can have great K/V performance with relatively poor analytics e.g. Marklogic or Oracle NoSQL SPARQL. or poor K/V perf but good analytic e.g. virtuoso or Oracle Semnet on its RDBMS. You can switch implementation and have completely different performance characteristics without needing to redo your data model etc...

As lead developer for the public facing rest and sparql endpoints of the UniProt consortium I know which is cheaper to run, SPARQL by an order of magnitude even if it uses more hardware.

Even inside the consortium developers who should have easy access to our SQL databases use our public SPARQL endpoint because it is easier to do so. That includes developers who have been writing SQL for decades and are not afraid of an explain plan. Opening a webpage is just quicker than getting SQL developer started and requires a whole lot less of tunneling.

Also a 1.5Tb on disk database such as sparql.uniprot.org is not going to be fun in all cases. The equivalent spread over the different production SQL databases is no fun either and no smaller (in this case actually federated until recently with oracle links, now some are postgres).

lolive• 9 years ago

One of the benefit of SPARQL is that you can extract a subset of a given dataset as RDF. And can inject it into another RDF graph.

Eventually, you can build-up your dataset by picking subsets of other datasets, and link your own data graph with all that.

(The top of the top is to use SPARQL federated query, so you can do all that a query-time).

If you consider SPARQL as a way to implement REST API, it is the most flexible API a data producer can provide: you can run whatever query on my dataset, I force nothing.

What I see as a failure in the SPARQL ecosystem, it is the lack of SPARQL query repositories for all public datasets.

I tried to develop a tool for that (cf datao.net) but it never took off.

anon12532• 9 years ago

For those who like to know a conceptually a bit more about RDF/Sparql: https://joelkuiper.eu/semantic-web

Bonus: my SPARQL Clojure wrapper https://github.com/joelkuiper/yesparql

SPARQL Protocol for RDF

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