s | p_blank | o_blank |
---|---|---|
/id/statistical-geography/S01001308 | http://www.w3.org/1999/02/22-rdf-syntax-ns#type | geosparql: Geometry |
/id/statistical-geography/S01001308 | geosparql: asWKT | POLYGON ((-4.289348410845235 55.4696561637572, -4.290520054582934 55.46967018707348, -4.290544357926891 55.470361809836774, -4.289717434671257 55.4708356769447, -4.28588182782603 55.470449008367616, -4.284753478393355 55.47101428815172, -4.285546371943022 55.47094062777025, -4.285656587425296 55.471477849509654, -4.286323024135968 55.471510338183116, -4.286739596322241 55.47241933050758, -4.289118216983262 55.474145491373015, -4.289910293892205 55.47388799384158, -4.290004926973198 55.474973772687, -4.288820443862457 55.475013911145396, -4.289020874481515 55.47546855042228, -4.288142435911968 55.47560182462245, -4.287847172090902 55.47514895721542, -4.286938162400186 55.47530077042707, -4.286637009678224 55.476384959500386, -4.28436401530027 55.4723828135786, -4.285085895424424 55.47227945387444, -4.281388145166799 55.46962509250098, -4.282938300166505 55.469344513772654, -4.289348410845235 55.4696561637572)) |
The most flexible way to access the data is by using SPARQL, a query language, analagous to SQL for relational databases, for retrieving and manipulating data from graph databases like ours. We support SPARQL 1.1 query syntax. Many online tutorials are available.
To submit a SPARQL query from your code, you issue an HTTP GET or POST to our endpoint:http://statistics.gov.scot/sparql
, with the query itself as a url-encoded parameter called query
.
For example, to run the following simple SPARQL query and get the results as JSON:
SELECT * WHERE {?s ?p ?o} LIMIT 10
Issue a POST to the endpoint, with the query in the body, and an Accept header of sparql-results+json
:
POST http://statistics.gov.scot/sparql HTTP/1.1
Host: statistics.gov.scot
Accept: application/sparql-results+json
Content-Type: application/x-www-form-urlencoded
query=SELECT+%2A+WHERE+%7B%3Fs+%3Fp+%3Fo%7D+LIMIT+10
Issue a GET to the following URL (note the .json
extension - see the formats section for more detail on this):
GET http://statistics.gov.scot/sparql.json?query=SELECT+%2A+WHERE+%7B%3Fs+%3Fp+%3Fo%7D+LIMIT+10
Scroll down to the end of this page for examples of both of these methods in a few different languages.
As with other aspects of our API, to get the data in different formats, you can use either (a) a format extension or (b) an HTTP Accept header. Available result formats depend on the type of SPARQL query. There are four main forms:
SELECT
queries return tabular results, and the formats available reflect this:
Format | Extensions | Accept Headers |
---|---|---|
XML | .xml |
application/xml, application/sparql-results+xml |
JSON | .json |
application/json, application/sparql-results+json |
Text | .txt, .text | text/plain |
CSV | .csv | text/csv |
CONSTRUCT
and DESCRIBE
queries return graph data, so the results are available in the same formats as our resource APIs:
Format | Extensions | Accept Headers |
---|---|---|
RDF/XML | .rdf | application/rdf+xml |
N-triples | .nt, .txt, .text | application/n-triples, text/plain |
Turtle | .ttl | text/turtle |
JSON-LD | .json | application/ld+json, application/json |
ASK
queries return a boolean result:
Format | Extensions | Accept Headers |
---|---|---|
XML | .xml | application/xml, application/sparql-results+xml |
JSON | .json | application/json, application/sparql-results+json |
Text | .txt, .text | text/plain |
We accept page
and per_page
parameters for paginating the results of SELECT queries (we automatically modify your query to apply LIMIT
and OFFSET
clauses). For other query types (i.e. DESCRIBE, CONSTRUCT, ASK), pagination like this doesn’t make so much sense, so these parameters are ignored.
For requests made through the website (i.e. HTML format), the page size is defaulted to 20. For requests to our sparql endpoint for data formats (i.e. non-HTML), there will be no defaults for these parameters (i.e. results are unlimited. For performance reasons we generally advise LIMITing your query if possible).
You can parameterise your SPARQL by including %{tokens}
in your queries, and providing values for the tokens in the request parameters.
Note that the following tokens are reserved and cannot be used as parameters for substitution:
controller
action
page
per_page
id
commit
utf8
query
Our servers are configured to allow access from all domains. This means that if you’re writing JavaScript to request data from our server in to a web page hosted on another domain, your browser should check this header and allow it.
If you need to support very old browsers, you can additionally pass a callback
parameter and the results will be wrapped in that function. For example:
http://statistics.gov.scot/sparql.json?callback=myCallbackFunction&query=SELECT+%2A+WHERE+%7B%3Fs+%3Fp+%3Fo%7D+LIMIT+10
This help topic on the jQuery website has more details.
Here’s a couple of examples running a query using the widely available cURL command line program.
Request the results as XML, using a POST:
curl -X POST -H "Accept: application/sparql-results+xml" -d "query=SELECT%20*%20WHERE%20%7B%3Fs%20%3Fp%20%3Fo%7D%20LIMIT%2010" http://statistics.gov.scot/sparql
Request the results as JSON, using a GET:
curl -X GET -H "Accept: application/sparql-results+json" http://statistics.gov.scot/sparql?query=SELECT%20*%20WHERE%20%7B%3Fs%20%3Fp%20%3Fo%7D%20LIMIT%2010
This example HTML page uses jQuery to issue a POST to our SPARQL endpoint, requesting the results as JSON.
<!DOCTYPE html>
<html lang='en'>
<head>
<script src='http://code.jquery.com/jquery-1.9.1.min.js'></script>
</head>
<body>
<script type='text/javascript'>
var query = 'SELECT * WHERE {?s ?p ?o} LIMIT 10';
var url = 'http://statistics.gov.scot/sparql.json';
$.ajax({
method: 'POST',
dataType: 'json',
url: url,
data: {query: query},
success: function(data) {
alert('success: ' + data.results.bindings.length + ' results');
console.log(data);
}
});
</script>
</body>
</html>