Parameter Mapping

When creating a query it can be made more general by using special variables inside the query. Adding these variables allows for the API to insert given parameters that are used by the query, making it dynamic. Creating such a variable is done by adding a '_' between the '?' and the variable name, resulting in: ?_name With this variable name the parameter will replace the variable as a simple literal, by adding another term after the variable name the parameter will be interpreted differently. When using:

• ?_name_en it will be interpreted as a literal written in English, this can be done with any language tag.
• ?_name_integer it will be interpreted as an integer.
• ?_name_iri it will be interpreted as an IRI.
• ?_name_prefix_datatype it will be interpreted as a datatype of type ^^prefix:datatype.

When there will not always be a parameter to replace the variable two underscores can be used to create an optional parameter, resulting in: ?__name

This way of mapping the parameters is based on the conventions used by BASIL.

example

The code of the query would look like this (for more on the first seven lines you can read query decorators):

#+ summary: Returns the bands
#+ endpoint: http://dbpedia.org/sparql
#+ tags:
#+   - bands
#+ defaults:
#+   - type: http://dbpedia.org/ontology/Band
#+   - genre: http://dbpedia.org/resource/Grunge

PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX dbo: <http://dbpedia.org/ontology/>
PREFIX dbp: <http://dbpedia.org/property/>
PREFIX dbr: <http://dbpedia.org/resource/>

SELECT ?band WHERE {
  ?band a ?_type_iri .
  ?band dbo:genre ?__genre_iri .
  ?band dbo:activeYearsStartYear ?_year_xsd_date .

} 
LIMIT 30

Giving you control over the parameters in the API that looks like this: