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graphqlsparqlrdfsemantic-webontology

What is the difference between GraphQL and SPARQL?

I'm doing a lot of research right now on Semantic Web and complex data models that represent relationships between individuals and organizations. I knew a little semantic ontologies although I never understood what it was used if not make graphs.

I saw on university wiki that the language to question an ontology is the SPARQL (tell me if I'm wrong).

But recently I saw a company that had created a semantic ontology put it in the form of GraphQL that I did not know (https://diffuseur.datatourisme.gouv.fr/graphql/voyager/).

It seems to me that semantic ontologies are made to better find information, for example to make a chatbot (it's what I want to do), but here they transformed a semantic ontology into an API, is it right? To make a GraphQL, should I build first a semantic ontology?

Could you explain to me a little the difference between all this, honestly it's a little vague for me.

Solution

  • Context

    Datatourisme is a platform that allows to publish (via the Producteur component) and to consume (via the Diffuseur component) POI-related open data.

    It seems you have linked to a particular application developed over Diffuseur with a help of GraphQL Voyager. The application illustrates capabilities of the GraphQL API exposed by Diffuseur.

    The API documentation is available here (in French):

    Problem

    • Datatourisme stores data in the RDF format (presumably using the Blazegraph triplestore)
    • Datatourisme provides access via GraphQL (not SPARQL)

    Why RDF

    • Partly due to some "schemaless", RDF is convenient in heterogeneous data integration tasks:

      Tourism national ontology structuring in a common sharing format the whole tourism data extracted from different official French data bases: entertainment and events, natural and cultural sites, leisure and sports activities, touristic products, tours, accomodations, shops, restaurants.

    • RDF is semantic: in particular, RDF is self-describing.

    SPARQL

    • SPARQL is W3C-standardized language for RDF querying. There were also proposed other RDF query languages.

      BTW, it is possible to query non-RDF sources with SPARQL, e. g. defining R2RML mappings.

    • RDF self-descibeness and SPARQL standardness remove the need to create or to learn a new (shitty) API every day.

    GraphQL

    • Similar to SPARQL, GraphQL allows to avoid multiple requests.

    • GraphQL allows to wrap different data sources of different kinds, but typically they are REST APIs.

      As you can see, it is possible to wrap a SPARQL endpoint (there also exists HyperGraphQL).

    Why GraphQL

    Why Datatourisme have preferred GraphQL?

    • GraphQL is closer to developers and technologies they use en masse. In the past, JSON-LD had the same motivation (however, see my note about JSON-LD here).

    • As it seems, Diffuseur's GraphQL layer provides API keys support and prevents too complex SPARQL queries.

    Are data still semantic

    • The answer depends on what you mean by semantic. There was an opinion that even relational model is quite semantical...

    • I'd answer affirmatively, if it's possible to extract e. g. the comment to the :rcs property with GraphQL (and the answer seems to be negative).

    Conclusion

    Answering your direct question:

    • it is not necessary (though possible) to create a semantic ontology first in order to use GraphQL;
    • it is not necessary (though possible) to use GraphQL after creating a semantic ontology.

    Answering your indirect question:

    • probably you need a semantic ontology in order to build such chatbot;
    • probably you need something else in addition.

    See also: How is the knowledge represented in Siri – is it an ontology or something else?

    Update

    In addition to HyperGraphQL, there are other interesting convergence projects: