linked-data

Search Multiple Queries from List in SPARQL

由 霸气de小男生 提交于 2019-12-08 19:01:27
I want to find sales data for a set of 300 addresses using the UK Land Registry database. The database permits SPARQL queries, however I am completely new to SPARQL, and do not know how to make multiple queries at once (e.g. search for 300 addresses in one SPARQL query). This is an example land registry query for a single address. So I have two questions: 1) How can I search for multiple addresses in one query? 2) Is there a way to connect a database list of addresses to automate the query? Help and direction will be hugely appreciated. In the example query, the first five triple patterns in

How to install SILK workbench?

由 浪子不回头ぞ 提交于 2019-12-08 10:05:17
问题 I want to install Silk - The Linked Data Integration Framework. I have downloaded latest version (2.6.1) of SILK WorkBench (https://github.com/silk-framework/silk/releases). I want to install it in both Mac and Windows Machine. Project README file is saying that "The bin-folder contains scripts for running the Silk Workbench on Windows, Linux and iOS." I have tried to run silk-workbench.bat file. However it is giving me following errors. Mac: ./silk-workbench.bat: line 1: @REM: command not

Linked Data (RDF) Content Negotiation with apache

由 孤者浪人 提交于 2019-12-08 07:48:52
问题 I was wondering if someone could provide me with the typical rule, to serve the appropriate file when a resource is requested, with respect to the content type required. To be more specific here is my situation: I have a purl URL that i redirect to an URL on my apache server. I would like to resource URL to be like a generic URL for the resource, and then serve the appropriate doc depending on the content Type: RDF, TTL, or HTML. Hence i would like to know how to do that within the .htaccess

Search Multiple Queries from List in SPARQL

由 最后都变了- 提交于 2019-12-08 07:42:33
问题 I want to find sales data for a set of 300 addresses using the UK Land Registry database. The database permits SPARQL queries, however I am completely new to SPARQL, and do not know how to make multiple queries at once (e.g. search for 300 addresses in one SPARQL query). This is an example land registry query for a single address. So I have two questions: 1) How can I search for multiple addresses in one query? 2) Is there a way to connect a database list of addresses to automate the query?

SPARQL: How to obtain label in available languages if first option is not available

由 [亡魂溺海] 提交于 2019-12-07 05:23:21
问题 If a Wikidata resource returned by my query has no available label in the language I filtered for I obtained an empty cell. SELECT * WHERE { ?country wdt:P31 wd:Q6256. ?country rdfs:label ?country_name FILTER(LANG(?country_name) = 'jbo'). } link How to request to have a label returned in one of any of the available languages if the first language fails? 回答1: First, prefer langMatches for checking language tags. This is especially important in your case, since you might want, for instance, a

Difference between rdf:seeAlso and rdfs:seeAlso

由 不羁岁月 提交于 2019-12-06 09:27:59
What is the difference between rdf:seeAlso and rdfs:seeAlso ? When I can use rdf:seeAlso and when I can use rdfs:seeAlso ? Can you do any examples? First, note that rdf and rdfs are prefixes commonly used to reference the RDF syntax and RDF schema vocabularies respectively. The rdf is typically used for http://www.w3.org/1999/02/22-rdf-syntax-ns# , so that rdf:seeAlso would expand to http://www.w3.org/1999/02/22-rdf-syntax-ns#seeAlso . However, if you follow the vocabulary reference, you won't find a term defined for seeAlso . The RDF syntax is used for basic types such as rdf:type, rdf

DISTINCT only on one value with SPARQL

由 点点圈 提交于 2019-12-05 20:35:51
问题 I want to retrieve with SPARQL the list of the italian cities with more than 100k of population and I'm using the following query: PREFIX dbo: <http://dbpedia.org/ontology/> SELECT ?city ?name ?pop WHERE { ?city a dbo:Settlement . ?city foaf:name ?name . ?city dbo:populationTotal ?pop . ?city dbo:country ?country . ?city dbo:country dbpedia:Italy . FILTER (?pop > 100000) } In the results I get for example in two different lines (which represent the same entity, but with different names): http

SPARQL: How to obtain label in available languages if first option is not available

由 江枫思渺然 提交于 2019-12-05 10:20:05
If a Wikidata resource returned by my query has no available label in the language I filtered for I obtained an empty cell. SELECT * WHERE { ?country wdt:P31 wd:Q6256. ?country rdfs:label ?country_name FILTER(LANG(?country_name) = 'jbo'). } link How to request to have a label returned in one of any of the available languages if the first language fails? Joshua Taylor First, prefer langMatches for checking language tags. This is especially important in your case, since you might want, for instance, a label in English, and langMatches(lang(?label), "en") will find a label with the tag "en", or

Modelling an equivalent of database NULL in RDF

由 岁酱吖の 提交于 2019-12-04 12:03:51
问题 I would like to know if there is a standard or generally accepted way of representing an equivalent of NULL used in databases for RDF data. More specifically, I'm interested in a way to distinguish the following cases for a value o of a property p ( p is the predicate, o the object of an RDF triple): The value is not applicable , i.e. property p does not exist or does not make sense in the context. The value is unknown , i.e. it should be there but we don't know it. The value doesn't exist ,

Sparql query with Blank node can be complex

由 痞子三分冷 提交于 2019-12-04 06:10:58
I read this blog article, Problems of the RDF model: Blank Nodes , and there's mentioned that using blank nodes can complicate the handling of data. Can you give me an example why using blank nodes is difficult to perform a SPARQL query? I do not understand the complexity of blank nodes. Can you explain me the meaning and semantics of an existential variable? I do not understand clearly this explanation given in the RDF Semantics Recommendation, 1.5. Blank Nodes as Existential Variables . Joshua Taylor Existential Variables In the (first-order) predicate calculus, there is existential
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