GraphStore`
GraphStore`

SPARQLVariable

SPARQLVariable["var"]

represents a variable with label "var" in a SPARQL query.

更多信息和选项

  • SPARQLVariable["x"] is used in SPARQL graph patterns and expressions to distinguish a variable with label "x" from a string literal "x".
  • The SPARQLVariable wrapper is optional in places where only variables can appear.
  • A SPARQLVariable can appear in any position of an RDFTriple.
  • An RDFTriple that contains a SPARQLVariable is also known as a triple pattern.

范例

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基本范例  (1)

Given an RDFStore about people:

Query all persons together with their first name:

Get the first and last name:

Possible Issues  (1)

Given an RDFStore about people:

Define a pattern that matches the first and last name:

The strings "first" and "last" in the "concat" function are interpreted as literals:

To refer to the variables use the SPARQLVariable wrapper:

Wolfram Research (2019)，SPARQLVariable，Wolfram 语言函数，https://reference.wolfram.com/language/GraphStore/ref/SPARQLVariable.html.

文本

Wolfram Research (2019)，SPARQLVariable，Wolfram 语言函数，https://reference.wolfram.com/language/GraphStore/ref/SPARQLVariable.html.

CMS

Wolfram 语言. 2019. "SPARQLVariable." Wolfram 语言与系统参考资料中心. Wolfram Research. https://reference.wolfram.com/language/GraphStore/ref/SPARQLVariable.html.

APA

Wolfram 语言. (2019). SPARQLVariable. Wolfram 语言与系统参考资料中心. 追溯自 https://reference.wolfram.com/language/GraphStore/ref/SPARQLVariable.html 年

BibTeX

@misc{reference.wolfram_2024_sparqlvariable, author="Wolfram Research", title="{SPARQLVariable}", year="2019", howpublished="\url{https://reference.wolfram.com/language/GraphStore/ref/SPARQLVariable.html}", note=[Accessed: 22-November-2024 ]}

BibLaTeX

@online{reference.wolfram_2024_sparqlvariable, organization={Wolfram Research}, title={SPARQLVariable}, year={2019}, url={https://reference.wolfram.com/language/GraphStore/ref/SPARQLVariable.html}, note=[Accessed: 22-November-2024 ]}