SPARQL Construct

LDIO Component Name: Ldio:SparqlConstructTransformer see reference guide

Apache Nifi Component Name: SPARQL Interactions Processors see reference guide

The SPARQL Construct Transformer will modify the model based on the given SPARQL Construct Query.

SPARQL Construct is a query language used in semantic Web technologies to create RDF (Resource Description Framework) graphs from existing RDF data. It allows users to specify a pattern of data they wish to extract from the RDF data and construct a new graph based on that pattern.

The SPARQL Construct query language provides a powerful way to create new RDF data by using existing data as the input. It can be used to transform RDF data into different formats, as well as to simplify the structure of RDF data by aggregating or filtering data.

This SPARQL Construct Transfomer building block can be used to execute model transformations.

Splitting models using SPARQL Construct

This component can be used to split models into multiple models using graphs. For example, the below query will create a dataset containing multiple models defined by ‘GRAPH’. The SPARQL construct component will extract all named models from the dataset and add all statements from the default model. The component will then return a collection of models.

CONSTRUCT {
    GRAPH ?s {
        ?s ?p ?o
    }
}
WHERE { ?s ?p ?o }

SPARQL functions

We support some additional geo functions that can call inside your SPARQL Construct query,

with the following namespace:

prefix geoc: https://opengis.net/def/function/geosparql/custom#

Function	Description	Input	Output
geoc:lineAtIndex	get LineString from MultiLineString by index.	MultiLineString(wktLiteral) & index	LineString(wktLiteral)
geoc:firstCoordinate	get first Coordinate of LineString.	LineString(wktLiteral)	Coordinate(wktLiteral)
geoc:lastCoordinate	get last Coordinate of LineString.	LineString(wktLiteral)	Coordinate(wktLiteral)
geoc:lineLength	calculate total line length of LineString.	LineString(wktLiteral)	distance in meters
geoc:midPoint	calculate midpoint of LineString.	LineString(wktLiteral)	Coordinate(wktLiteral)
geoc:pointAtFromStart	calculate point on LineString by distance.	LineString(wktLiteral) & distance in meters	Coordinate(wktLiteral)