RDF.Query.execute
You're seeing just the function
execute
, go back to RDF.Query module for more information.
Execute the given query
against the given graph
.
The query
can be given directly as RDF.Query.BGP
struct created with one
of the builder functions in this module or as basic graph pattern expression
accepted by bgp/1
.
The result is a list of maps with the solutions for the variables in the graph
pattern query and will be returned in a :ok
tuple. In case of an error a
:error
tuple is returned.
Example
Let's assume we have an example_graph
with these triples:
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix ex: <http://example.com/> .
ex:Outlaw
foaf:name "Johnny Lee Outlaw" ;
foaf:mbox <mailto:jlow@example.com> .
ex:Goodguy
foaf:name "Peter Goodguy" ;
foaf:mbox <mailto:peter@example.org> ;
foaf:friend ex:Outlaw .
iex> {:_, FOAF.name, :name?} |> RDF.Query.execute(example_graph())
{:ok, [%{name: ~L"Peter Goodguy"}, %{name: ~L"Johnny Lee Outlaw"}]}
iex> [
...> {:_, FOAF.name, :name?},
...> {:_, FOAF.mbox, :mbox?},
...> ] |> RDF.Query.execute(example_graph())
{:ok, [
%{name: ~L"Peter Goodguy", mbox: ~I<mailto:peter@example.org>},
%{name: ~L"Johnny Lee Outlaw", mbox: ~I<mailto:jlow@example.com>}
]}
iex> query = [
...> {:_, FOAF.name, :name?},
...> {:_, FOAF.mbox, :mbox?},
...> ] |> RDF.Query.bgp()
...> RDF.Query.execute(query, example_graph())
{:ok, [
%{name: ~L"Peter Goodguy", mbox: ~I<mailto:peter@example.org>},
%{name: ~L"Johnny Lee Outlaw", mbox: ~I<mailto:jlow@example.com>}
]}
iex> [
...> EX.Goodguy, FOAF.friend, FOAF.name, :name?
...> ] |> RDF.Query.path() |> RDF.Query.execute(example_graph())
{:ok, [%{name: ~L"Johnny Lee Outlaw"}]}