Re: How do you explore a SPARQL Endpoint?

The RDF Pipeline Framework also has a perl script that reads RDF (Turtle), figures out the data's implied schema -- classes and predicates -- and outputs a summary. The code is open source (Apache 2.0 licensed) and resides on github: https://github.com/dbooth-boston/rdf-pipeline/blob/master/to

Re: How do you explore a SPARQL Endpoint?

Sorry, ignore priore email, it was sent prematurely. We had occasion to need the ability to eplore a triple store in an application we were building for a client using a triple store (TS). Triples were being created using scripts and being updated into the TS,we also had an application that allowe

Re: How do you explore a SPARQL Endpoint?

We had occasion to need this ability on an application we were building for a client using a triple store (TS). Triples were being created using scripts and being updated into the TS,we also had an application that allowed users to enter information which added more triples. All of this was backed

Re: How do you explore a SPARQL Endpoint?

This work [1] might be helpful to some people. It automatically learns a "schema" from a given RDF dataset, including most probable classes and properties and most probable relations/paths between given classes and etc. Next, it can automatically translate a casual user's intuitive graph query or s

Re: How do you explore a SPARQL Endpoint?

On Sun, Jan 25, 2015 at 11:44 PM, Bernard Vatant wrote: > Hi Pavel > > Very interesting discussion, thanks for the follow-up. Some quick answers > below, but I'm currently writing a blog post which will go in more details > on the notion of Data Patterns, a term I've been pushing last week on the

Re: How do you explore a SPARQL Endpoint?

Hi Pavel Very interesting discussion, thanks for the follow-up. Some quick answers below, but I'm currently writing a blog post which will go in more details on the notion of Data Patterns, a term I've been pushing last week on the DC Architecture list, where it seems to have gained some traction.

Re: How do you explore a SPARQL Endpoint?

Hi Bernard, On Fri, Jan 23, 2015 at 11:28 AM, Bernard Vatant wrote: > Hi Pavel > > Maybe what you are missing is that RDF data, by design, do not need a > schema. Right, I am aware of that. I think it's important to separate the absence of the schema from the absence of an explicit representatio

Re: How do you explore a SPARQL Endpoint?

Just to give some example of what the situation is, consider the profile of Dublin Core which is specified at page 32 in the following document http://www.adobe.com/content/dam/Adobe/en/devnet/xmp/pdfs/XMPSpecificationPart1.pdf which quotes "The XMP data modelling of these is consistent with app

Re: How do you explore a SPARQL Endpoint?

The optimistic approach: SELECT * WHERE { ?ontology a owl:Ontology . OPTIONAL { ?ontology owl:versionIRI ?version } } Then retrieve those separately over HTTP. (Trying to extract the ontology over SPARQL would be much more work - there might or might not live in separate graphs and might and

Re: How do you explore a SPARQL Endpoint?

On 1/23/15 4:37 AM, Pavel Klinov wrote: Alright, so this isn't an answer and I might be saying something totally silly (since I'm not a Linked Data person, really). If I re-phrase this question as the following: "how do I extract a schema from a SPARQL endpoint?", then it seems to pop up quite o

Re: How do you explore a SPARQL Endpoint?

Hi Pavel Maybe what you are missing is that RDF data, by design, do not need a schema. Since the very notion of schema for RDF data has no meaning at all, and the absence of schema is a bit frightening, people tend to give it a lot of possible meanings, depending on your closed world or open world

Re: How do you explore a SPARQL Endpoint?

Alright, so this isn't an answer and I might be saying something totally silly (since I'm not a Linked Data person, really). If I re-phrase this question as the following: "how do I extract a schema from a SPARQL endpoint?", then it seems to pop up quite often (see, e.g., [1]). I understand that t

Re: How do you explore a SPARQL Endpoint?

Complementary: SELECT count (*) WHERE { ?s ?p ?o . } It is useful to know the number of triples in the sparql endpoint. Regards. On Thu, 22 Jan 2015 15:27:24 +0100 Bernard Vatant wrote: Hi Juan My strategy is as following Q1 : Which types are used? SELECT DISTINCT ?type WHERE {?x rdf:typ

RE: How do you explore a SPARQL Endpoint?

, 2015 11:01 AM To: Bernard Vatant Cc: Semantic Web; public-lod public Subject: Re: How do you explore a SPARQL Endpoint? May be not just looking at the classes and properties but looking at their frequencies using counts can give a better idea about what sort of data is exposed. If there is a Void

Re: How do you explore a SPARQL Endpoint?

Hi Juan, All, We are actually working on some solutions that can help people to explore what is inside a “dataset” deployed in an endpoint, to have a better and more exhaustive view about the information and structure of the data. The proposed SPARQL queries are excellent, however most of th

Re: How do you explore a SPARQL Endpoint?

May be not just looking at the classes and properties but looking at their frequencies using counts can give a better idea about what sort of data is exposed. If there is a Void information it certainly helps. Tools such as http://data.aalto.fi/visu also help. Similar approach described here [1] .

Re: How do you explore a SPARQL Endpoint?

Some other pointers and queries from https://github.com/fadmaa/rdf-analytics/blob/master/queries.txt == query 7 (graph summary query)== /* this computes the "schema" of an RDF dataset. This is based on the queries generated by Sindice Sparqled: https://github.com/sindice/sparql

Re: How do you explore a SPARQL Endpoint?

Interesting to note that the answers so far are converging towards looking first for types and predicates, but bottom-up from the data, and not queries looking for a declared model layer using RDFS or OWL, such as e.g., SELECT DISTINCT ?class WHERE { {?class a owl:Class} UNION {?class a rdfs:Class

Re: How do you explore a SPARQL Endpoint?

It's also good to start exploring with just the ?predicates, because not all resources necessarily have a type. (Or predicates on a type might not always be on all instances of that types). Also, whenever you find a new type of resource - remember to explore both what it links to ?p ?o ; and wh

Re: How do you explore a SPARQL Endpoint?

In order to explore the schema (or better said: the types of the actual nodes and properties) you could do: select ?type1 ?pred ?type2 where { ?subj ?pred ?obj. ?subj a ?type1. ?obj a ?type2. } Depending on the triple store, it could be useful to filter some trivial types. Il 22/01/15 15:28

Re: How do you explore a SPARQL Endpoint?

SELECT DISTINCT ?type WHERE { ?x rdf:type ?type . } SELECT DISTINCT ?p WHERE { ?s ?p ?o . } then SELECT ?s WHERE { ?s a } LIMIT 100 and then DESCRIBE or SELECT ?p ?o WHERE { ?p ?o . } Having some statisti

Re: How do you explore a SPARQL Endpoint?

Look in the Service Description and see what they put in there. Otherwise see if there is any documentation linked from the sparql endpoint page. On Thu, Jan 22, 2015 at 3:19 PM, Luca Matteis wrote: > "Give me all your types" seems the most sensible thing to do. > Otherwise full text search. >

Re: How do you explore a SPARQL Endpoint?

Hi Juan My strategy is as following Q1 : Which types are used? SELECT DISTINCT ?type WHERE {?x rdf:type ?type} Q2 : Which predicates are used? SELECT DISTINCT ?p WHERE {?x ?p ?o} Q3 : Which predicates are used by instances of the type :foo found in Q1 I'm interested in SELECT DISTINCT ?p WHERE

Re: How do you explore a SPARQL Endpoint?

On 2015-01-22 15:09, Juan Sequeda wrote: Assume you are given a URL for a SPARQL endpoint. You have no idea what data is being exposed. What do you do to explore that endpoint? What queries do you write? Juan Sequeda +1-575-SEQ-UEDA www.juansequeda.com I suspect that the obligatory query tha

Re: How do you explore a SPARQL Endpoint?

Hi the most basic query is the usual query for concepts, something like: SELECT DISTINCT ?concept WHERE { ?uri a ?concept. } then, given a specific concept, you can infer from the data what are the predicates/properties for it: SELECT DISTINCT ?prp WHERE { [] ?prp . } and so on... Apart from

Re: How do you explore a SPARQL Endpoint?

"Give me all your types" seems the most sensible thing to do. Otherwise full text search. On Thu, Jan 22, 2015 at 3:09 PM, Juan Sequeda wrote: > Assume you are given a URL for a SPARQL endpoint. You have no idea what data > is being exposed. > > What do you do to explore that endpoint? What queri

How do you explore a SPARQL Endpoint?

Assume you are given a URL for a SPARQL endpoint. You have no idea what data is being exposed. What do you do to explore that endpoint? What queries do you write? Juan Sequeda +1-575-SEQ-UEDA www.juansequeda.com