SPARQL 1.2 Query Results JSON Format

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 First Public Working Draft using the Recommendation track.

Publication as a First Public 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.

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 2 November 2021 W3C Process Document.

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.

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.

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

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

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.

The optional "link" member gives an array of URIs, as strings, to refer for further information. The format and content of these link references is not defined by this document.

"link" : [ "http://example/dataset/metadata.ttl" ]

The value of the "results" member is an object with a single key, "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" : []

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	`{ "type": "literal", "value": "S", "xml:lang": "L"}`
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", "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.

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

The "link" member has the same format as the SELECT "link" member.

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

This section is not normative.

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" }
      }
    ]
  }
}

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" }
          }
        }
      }
    ]
  }
}

The Internet Media Type / 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.

[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. Birte Glimm; Chimezie Ogbuji. W3C. W3C Working Draft. URL: https://w3c.github.io/sparql-entailment/spec/
[SPARQL12-FEDERATED-QUERY]: SPARQL 1.2 Federated Query. Eric Prud'hommeaux; Carlos Buil Aranda. W3C. W3C Working Draft. URL: https://w3c.github.io/sparql-federated-query/spec/
[SPARQL12-GRAPH-STORE-PROTOCOL]: SPARQL 1.2 Graph Store HTTP Protocol. Chimezie Ogbuji. W3C. W3C Working Draft. URL: https://w3c.github.io/sparql-graph-store-protocol/spec/
[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. Lee Feigenbaum; Gregory Williams; Kendall Clark; Elias Torres. W3C. W3C Working Draft. URL: https://w3c.github.io/sparql-protocol/spec/
[SPARQL12-QUERY]: SPARQL 1.2 Query Language. Steven Harris; Andy Seaborne. W3C. W3C Working Draft. URL: https://w3c.github.io/sparql-query/spec/
[SPARQL12-RESULTS-CSV-TSV]: SPARQL 1.2 Query Results CSV and TSV Formats. Andy Seaborne. W3C. W3C Working Draft. URL: https://w3c.github.io/sparql-results-csv-tsv/spec/
[SPARQL12-RESULTS-XML]: SPARQL 1.2 Query Results XML Formats. Sandro Hawke; Dave Beckett; Jeen Broekstra. W3C. W3C Working Draft. URL: https://w3c.github.io/sparql-results-xml/spec/
[SPARQL12-SERVICE-DESCRIPTION]: SPARQL 1.2 Service Description. Gregory Williams. W3C. W3C Working Draft. URL: https://w3c.github.io/sparql-service-description/spec/
[SPARQL12-UPDATE]: SPARQL 1.2 Update. Paula Gearon; Alexandre Passant; Axel Polleres. W3C. W3C Working Draft. URL: https://w3c.github.io/sparql-update/spec/

SPARQL 1.2 Query Results JSON Format

Abstract

Status of This Document

2. Introduction

3. JSON Results Object

4. Variable Binding Results

4.1 "head"

4.1.1 "vars"

4.1.2 "link"

4.2 "results"

4.2.1 "bindings"

4.2.2 Encoding RDF terms

5. Boolean Results

5.1 "head"

5.1.1 "link"

5.2 "boolean"

6. Examples

6.1 Variable Binding Results Examples

6.2 Variable Binding Results Examples with Quoted Triples

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

8. Privacy Considerations

9. Security Considerations

10. Internationalization Considerations

A. Change Log

B. Index

B.1 Terms defined by this specification

B.2 Terms defined by reference

C. References

C.1 Informative references

SPARQL 1.2 Query Results JSON Format

Abstract

Status of This Document

1. Set of Documents

2. Introduction

3. JSON Results Object

4. Variable Binding Results

4.1 "head"

4.1.1 "vars"

4.1.2 "link"

4.2 "results"

4.2.1 "bindings"

4.2.2 Encoding RDF terms

5. Boolean Results

5.1 "head"

5.1.1 "link"

5.2 "boolean"

6. Examples

6.1 Variable Binding Results Examples

6.2 Variable Binding Results Examples with Quoted Triples

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

8. Privacy Considerations

9. Security Considerations

10. Internationalization Considerations

A. Change Log

B. Index

B.1 Terms defined by this specification

B.2 Terms defined by reference

C. References

C.1 Informative references