How is Jena able to index and search/compare properties with different data
types?
For example if I have this graph
:alice :foobar "2021-07-16"^^xsd:date;
:alice :foobar "foobar"^^xsd:string;
:alice :foobar "42"^^xsd:integer;
> Sent: Friday, July 16, 2021 at 10:06 AM
> From: "Andy Seaborne" <a...@apache.org>
> To: users@jena.apache.org
> Subject: Re: Does Jena use duck typing?
>
> Literals are always datatyped in RDF. No guessing.
>
>
>
> There syntax conveniences:
>
> "abc" is the same as writing "abc"^^xsd:string.
>
> The specs say to prefer writing output without ^^xsd:string.
>
> In Turtle and related syntaxes:
>
> 42 is an xsd:integer == "42"^^xsd:integer
>
> 42.99 is an xsd:decimal
>
> 42e0 is an xsd;double.
>
> "2021-07-16" is string.
> "2021-07-16"^^xsd;date is a date.
>
> and language strings "abc"@en have datatype rdf:langString.
>
> On 16/07/2021 08:35, Laura Morales wrote:
> > When I insert new triples into a Jena/Fuseki store, are *all* the quoted
> > literals treated as strings by default unless I specify the type explicitly
> > (eg. xsd:dateTime)? Or does Jena use duck typing to determine the best type
> > fit for storing the value?
> > What about numbers instead? Will Jena store 42 as an xsd:integer and 42.99
> > as xsd:double if I don't explicitly write the type?
> >
> > How can I specify a set of constraints in Fuseki for all the properties of
> > my model? For example "this property is a double, with range [1.0 .. 2.0]"
> > (the same way that I can specify constraints on Postgres for example)?
>
> Using ontology/schema/shapes.
>
> Andy
>
