SPARQL 1.2 Query Results JSON Format

W3C Working Draft

More details about this document
This version:
https://www.w3.org/TR/2024/WD-sparql12-results-json-20240418/
Latest published version:
https://www.w3.org/TR/sparql12-results-json/
Latest editor's draft:
https://w3c.github.io/sparql-results-json/spec/
History:
https://www.w3.org/standards/history/sparql12-results-json/
Commit history
Test suite:
https://w3c.github.io/rdf-tests/
Latest Recommendation:
https://www.w3.org/TR/2013/REC-sparql11-results-json-20130321
Editors:
Andy Seaborne
Ruben Taelman
Gregory Williams
Thomas Pellissier Tanon
Former editors:
Andy Seaborne
Kendall Grant Clark
Lee Feigenbaum
Elias Torres
Feedback:
GitHub w3c/sparql-results-json (pull requests, new issue, open issues)
public-rdf-star-wg@w3.org with subject line [sparql12-results-json] … message topic … (archives)

Abstract

SPARQL is a set of standards for the query and update of RDF data, along with ways to access such data over the web. This document describes the representation of SELECT and ASK query results using JSON.

Status of This Document

This section describes the status of this document at the time of its publication. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at https://www.w3.org/TR/.

This specification is published by the RDF Star Working Group as part of the update of specifications for format and errata.

This document was published by the RDF-star Working Group as a Working Draft using the Recommendation track.

Publication as a Working Draft does not imply endorsement by W3C and its Members.

This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress. Future updates to this specification may incorporate new features.

This document was produced by a group operating under the W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.

This document is governed by the 03 November 2023 W3C Process Document.

2. Introduction

This document describes how to serialize SPARQL results (SELECT and ASK query forms) in a JSON format. The format is designed to be a complete representation of the information in the query results. The results of a SELECT query are serilialized as an array, where each array element is one "row" of the query results; the results of an ASK query give the boolean value of the query result.

An Internet Media Type is provided for application/sparql-results+json.

There is also a SPARQL 1.2 Query Results XML Format which follows a similar design pattern but uses XML as the serialization.

Unless otherwise noted in the section heading, all sections and appendices in this document are normative.

3. JSON Results Object

The results of a SPARQL Query are serialized in JSON as a single top-level JSON object. This object has a "head" member and either a "results" member or a "boolean" member, depending on the query form.

This example shows the results of a SELECT query. The query solutions are represented in an array which is the value of the "bindings" key, in turn part of an object that is the value of the "results" key:

{
  "head": { "vars": [ "book" , "title" ]
  } ,
  "results": { 
    "bindings": [
      {
        "book": { "type": "uri" , "value": "http://example.org/book/book6" } ,
        "title": { "type": "literal" , "value": "Harry Potter and the Half-Blood Prince" }
      } ,
      {
        "book": { "type": "uri" , "value": "http://example.org/book/book7" } ,
        "title": { "type": "literal" , "value": "Harry Potter and the Deathly Hallows" }
      } ,
      {
        "book": { "type": "uri" , "value": "http://example.org/book/book5" } ,
        "title": { "type": "literal" , "value": "Harry Potter and the Order of the Phoenix" }
      } ,
      {
        "book": { "type": "uri" , "value": "http://example.org/book/book4" } ,
        "title": { "type": "literal" , "value": "Harry Potter and the Goblet of Fire" }
      } ,
      {
        "book": { "type": "uri" , "value": "http://example.org/book/book2" } ,
        "title": { "type": "literal" , "value": "Harry Potter and the Chamber of Secrets" }
      } ,
      {
        "book": { "type": "uri" , "value": "http://example.org/book/book3" } ,
        "title": { "type": "literal" , "value": "Harry Potter and the Prisoner Of Azkaban" }
      } ,
      {
        "book": { "type": "uri" , "value": "http://example.org/book/book1" } ,
        "title": { "type": "literal" , "value": "Harry Potter and the Philosopher's Stone" }
      }
    ]
  }
}

This example shows the result from an ASK query:

{ 
  "head" : { } ,
  "boolean" : true
}

Other keys, with different names, may be present in the JSON Results Object but are not defined by this specification.

4. Variable Binding Results

The results of a SPARQL SELECT query are serialized as an array of bindings of variables. The value of the "head" key is an array of all variables projected in the query's SELECT clause.

4.1 "head"

The "head" member gives the variables mentioned in the results and may contain a "link" member.

{
"head" { 
   "vars" : [ ... ] ,
   "link" : [ ... ] }

4.1.1 "vars"

The "vars" member is an array giving the names of the variables used in the results. These are the projected variables from the query. A variable is not necessarily given a value in every query solution of the results.

"vars" : [ "book" , "title" ]

The order of variable names should correspond to the variables in the SELECT clause of the query, unless the query is of the form SELECT * in which case order is not significant.

4.2 "results"

The value of the "results" member is an object with a single key, "bindings".

4.2.1 "bindings"

The value of the "bindings" member is an array with zero or more elements, one element per query solution. Each query solution is a JSON object. Each key of this object is a variable name from the query solution. The value for a given variable name is a JSON object that encodes the variable's bound value, an RDF term. There are zero elements in the array if the query returned an empty solution sequence. Variables names do not include the initial "?" or "$" character. Each variable name that appears as a key within the "bindings" array will have appeared in the "vars" array in the results header.

A variable does not appear in an array element if it is not bound in that particular query solution.

The order of elements in the bindings array reflects the order, if any, of the query solution sequence.

"bindings" : [
  {
    "a" : { ... } ,
    "b" : { ... } 
  } ,
  {
    "a" : { ... } ,
    "b" : { ... } 
  }
]

If the query returns no solutions, an empty array is used.

"bindings" : []

4.2.2 Encoding RDF terms

An RDF term (IRI, literal, blank node, or quoted triple) is encoded as a JSON object. All aspects of the RDF term are represented. The JSON object has a "type" member and other members depending on the specific kind of RDF term.

RDF Term JSON form
IRI I {"type": "uri", "value": "I"}
Literal S {"type": "literal","value": "S"}
Literal S with language tag L without base direction { "type": "literal", "value": "S", "xml:lang": "L"}
Literal S with language tag L with base direction L { "type": "literal", "value": "S", "xml:lang": "L", "its:dir": "B"}
Literal S with datatype IRI D { "type": "literal", "value": "S", "datatype": "D"}
Blank node, label B {"type": "bnode", "value": "B"}
Quoted triple, with subject S, predicate P, and object O {"type": "triple", "value": {"subject": "S", "predicate": "P", "object": "O"}}

The blank node label is scoped to the results object. That is, two blank nodes with the same label in a single SPARQL Results JSON object are the same blank node. This is not an indication of any internal system identifier the SPARQL processor may use. Use of the same label in another SPARQL Results JSON object does not imply it is the same blank node.

The subject, predicate, and object of a quoted triple are encoded using the same format, recursively.

Note

The xml:lang and its:dir keys resemble terms in XML namespaces due to alignment with the SPARQL 1.2 Query Results XML Format specification, but such namespaces do not exist in JSON, which means that these keys are to be used "as is".

5. Boolean Results

The results of a SPARQL ASK query are serialized as a boolean value, giving the result of the query evaluation.

5.1 "head"

5.2 "boolean"

The result of an ASK query form are encoded by the "boolean" member, which takes either the JSON value true or the JSON value false.

"boolean" : true

6. Examples

This section is not normative.

6.1 Variable Binding Results Examples

The following JSON is a serialization of the XML document output.srx:

{
  "head": {
    "link": [ "http://www.w3.org/TR/rdf-sparql-XMLres/example.rq" ],
    "vars": [
      "x",
      "hpage",
      "name",
      "mbox",
      "age",
      "blurb",
      "friend"
    ]
  },
  "results": {
    "bindings": [
      {
        "x":     { "type": "bnode",   "value": "r1" },
        "hpage": { "type": "uri",     "value": "http://work.example.org/alice/" },
        "name":  { "type": "literal", "value": "Alice" },
        "mbox":  { "type": "literal", "value": "" },
        "blurb": {
          "datatype": "http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral",
          "type": "literal",
          "value": "<p xmlns=\"http://www.w3.org/1999/xhtml\">My name is <b>alice</b></p>"
        },
        "friend": { "type": "bnode", "value": "r2" }
      },
      {
        "x":      { "type": "bnode",   "value": "r2" },
        "hpage":  { "type": "uri",     "value": "http://work.example.org/bob/" },
        "name":   { "type": "literal", "value": "Bob", "xml:lang": "en" },
        "mbox":   { "type": "uri",     "value": "mailto:bob@work.example.org" },
        "friend": { "type": "bnode",   "value": "r1" }
      }
    ]
  }
}

6.2 Variable Binding Results Examples with Quoted Triples

The following JSON is a serialization of the XML document output-quoted.srx that contains quoted triples:

{
  "head": {
    "link": [ "http://www.w3.org/TR/rdf-sparql-XMLres/example-quoted.rq" ],
    "vars": [
      "x",
      "name",
      "quoted"
    ]
  },
  "results": {
    "bindings": [
      {
        "x":    { "type": "bnode",   "value": "r1" },
        "name": { "type": "literal", "value": "Alice" },
        "quoted": {
          "type": "triple",
          "value": {
            "subject":   { "type": "uri",     "value": "http://example.org/alice" },
            "predicate": { "type": "uri",     "value": "http://example.org/name" },
            "object":    { "type": "literal", "value": "Alice", "datatype": "http://www.w3.org/2001/XMLSchema#string" }
          }
        }
      },
      {
        "x":    { "type": "bnode",   "value": "r2" },
        "name": { "type": "literal", "value": "Bob", "xml:lang": "en" },
        "quoted": {
          "type": "triple",
          "value": {
            "subject":   { "type": "uri",     "value": "http://example.org/bob" },
            "predicate": { "type": "uri",     "value": "http://example.org/name" },
            "object":    { "type": "literal", "value": "Bob", "datatype": "http://www.w3.org/2001/XMLSchema#string" }
          }
        }
      }
    ]
  }
}

7. Internet Media Type, File Extension and Macintosh File Type

The Internet Media Type (formerly known as MIME Type) for the SPARQL Query Results JSON Format is "application/sparql-results+json".

It is recommended that SPARQL Query Results JSON Format files have the extension ".srj" (all lowercase) on all platforms.

It is recommended that SPARQL Query Results JSON Format files stored on Macintosh HFS file systems be given a file type of "TEXT".

This information that follows is intended to be submitted to the IESG for review, approval, and registration with IANA.

Type name:
application
Subtype name:
sparql-results+json
Required parameters:
None
Optional parameters:
None
Encoding considerations:
The encoding considerations of the SPARQL Query Results JSON Format is identical to those of the "application/json" as specified in [RFC4627].
Security considerations:
SPARQL query results uses URIs. See Section 7 of [RFC3986].
SPARQL query results uses IRIs. See Section 8 of [RFC3987].
The security considerations of the SPARQL Query Results JSON Format is identical to those of the "application/json" as specified in [RFC4627].
Interoperability considerations:
There are no known interoperability issues.
Published specification:
http://www.w3.org/TR/sparql11-results-json/
Applications which use this media type:
No known applications currently use this media type.
Additional information:
Magic number(s):
n/a
File extension(s):
".srj"
Macintosh file type code(s):
"TEXT"
Person & email address to contact for further information:
Andy Seaborne <public-rdf-dawg-comments@w3.org>
Intended usage:
COMMON
Restrictions on usage:
None
Author/Change controller:
The SPARQL specification is a work product of the World Wide Web Consortium's SPARQL Working Group. The W3C has change control over these specifications.

8. Privacy Considerations

TODO

9. Security Considerations

TODO

10. Internationalization Considerations

TODO

A. Change Log

This section is non-normative.

TODO

B. Index

B.1 Terms defined by this specification

B.2 Terms defined by reference

C. References

C.1 Informative references

[RFC3986]
Uniform Resource Identifier (URI): Generic Syntax. T. Berners-Lee; R. Fielding; L. Masinter. IETF. January 2005. Internet Standard. URL: https://www.rfc-editor.org/rfc/rfc3986
[RFC3987]
Internationalized Resource Identifiers (IRIs). M. Duerst; M. Suignard. IETF. January 2005. Proposed Standard. URL: https://www.rfc-editor.org/rfc/rfc3987
[RFC4627]
The application/json Media Type for JavaScript Object Notation (JSON). D. Crockford. IETF. July 2006. Informational. URL: https://www.rfc-editor.org/rfc/rfc4627
[SPARQL12-CONCEPTS]
SPARQL 1.2 Concepts. The W3C RDF-star Working Group. W3C. W3C Working Draft. URL: https://w3c.github.io/sparql-concepts/spec/
[SPARQL12-ENTAILMENT]
SPARQL 1.2 Entailment Regimes. Peter Patel-Schneider. W3C. 15 June 2023. W3C Working Draft. URL: https://www.w3.org/TR/sparql12-entailment/
[SPARQL12-FEDERATED-QUERY]
SPARQL 1.2 Federated Query. Ruben Taelman; Gregory Williams. W3C. 21 March 2024. W3C Working Draft. URL: https://www.w3.org/TR/sparql12-federated-query/
[SPARQL12-GRAPH-STORE-PROTOCOL]
SPARQL 1.2 Graph Store Protocol. Andy Seaborne; Thomas Pellissier Tanon. W3C. 16 June 2023. W3C Working Draft. URL: https://www.w3.org/TR/sparql12-graph-store-protocol/
[SPARQL12-NEW]
What’s New in SPARQL 1.2. The W3C RDF-star Working Group. W3C. W3C Working Draft. URL: https://w3c.github.io/sparql-new/spec/
[SPARQL12-PROTOCOL]
SPARQL 1.2 Protocol. Andy Seaborne; Ruben Taelman; Gregory Williams; Thomas Pellissier Tanon. W3C. 14 December 2023. W3C Working Draft. URL: https://www.w3.org/TR/sparql12-protocol/
[SPARQL12-QUERY]
SPARQL 1.2 Query Language. Olaf Hartig; Andy Seaborne; Ruben Taelman; Gregory Williams; Thomas Pellissier Tanon. W3C. 21 March 2024. W3C Working Draft. URL: https://www.w3.org/TR/sparql12-query/
[SPARQL12-RESULTS-CSV-TSV]
SPARQL 1.2 Query Results CSV and TSV Formats. Ruben Taelman; Gregory Williams; Thomas Pellissier Tanon. W3C. 10 November 2023. W3C Working Draft. URL: https://www.w3.org/TR/sparql12-results-csv-tsv/
[SPARQL12-RESULTS-XML]
SPARQL 1.2 Query Results XML Format. Ruben Taelman; Dominik Tomaszuk; Thomas Pellissier Tanon. W3C. 30 November 2023. W3C Working Draft. URL: https://www.w3.org/TR/sparql12-results-xml/
[SPARQL12-SERVICE-DESCRIPTION]
SPARQL 1.2 Service Description. Ruben Taelman; Gregory Williams. W3C. 14 December 2023. W3C Working Draft. URL: https://www.w3.org/TR/sparql12-service-description/
[SPARQL12-UPDATE]
SPARQL 1.2 Update. Ruben Taelman; Andy Seaborne; Thomas Pellissier Tanon. W3C. 28 September 2023. W3C Working Draft. URL: https://www.w3.org/TR/sparql12-update/