Query an Ontotext GraphDB repository with SPARQL from a FrameworX solution and show the result in a DataGrid that follows a tag.

How-to Guides → Solution Examples → Feature Examples → Data Foundation Examples → GraphDB SPARQL Query

Summary

The solution sends a SPARQL query to a GraphDB repository, receives the answer as a DataTable and shows it in a DataGrid. The query asks for every relationship of one character and the name of the object at the other end, for example starship → X-wing. A Text tag holds the character name, so changing the tag changes the table on screen.

The same pattern answers plant questions: replace the character with an equipment name and the relationships with feedsInto, and the query returns what is downstream of that equipment.

Technical Information

WebData row

In Reports → WebData, the row StarWars:

The row's Editor holds the query. {Tag.Character} is filled in with the tag value each time the query runs.

PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX voc: <https://swapi.co/vocabulary/>
SELECT ?relation ?item
WHERE {
  ?person rdfs:label "{Tag.Character}" ;
          ?rel ?obj .
  ?obj rdfs:label ?item .
  FILTER(STRSTARTS(STR(?rel), STR(voc:)))
  BIND(STRAFTER(STR(?rel), STR(voc:)) AS ?relation)
}
ORDER BY ?relation ?item

Tags

Script Task

The Server task QueryGraph runs every 10 seconds:

try
{
    @Tag.Err = "";
    DataTable t = await @Report.WebData.StarWars.SparqlQueryTableAsync();
    @Tag.Result = t;
    @Tag.Rows = t == null ? -1 : t.Rows.Count;
}
catch (Exception ex)
{
    @Tag.Err = ex.GetType().Name + ": " + ex.Message;
    @Info.Trace("SPARQL query failed: " + ex.Message);
}

Display

The main Display has a DataGrid with Data Source set to Tag.Result. It shows two columns, relation and item.

Expected result

Change Character while the solution runs, and the DataGrid shows the new character's relationships within 10 seconds.

Caveats

• The name must match the label in the graph exactly, including capital letters.
• {Tag.Character} is filled in only because the query is in the row's Editor. Query text passed as an argument to SparqlQueryTableAsync(query) is sent as written.
• The 10-second period suits a demonstration. In a solution, run the query on a tag change or from a button.

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