Query the semantic graph with SPARQL

Query the semantic graph with SPARQL

Shepard’s semantic substrate stores every semantic annotation as a triple in an n10s-managed RDF graph. The SPARQL playground lets you write SELECT and ASK queries against that graph and inspect the results in a table or raw JSON — directly from the browser.

Open the playground

From the top navigation bar choose Tools → SPARQL playground, or go to /semantic/sparql directly.

You can also open it pre-filled from an entity’s context menu:

• On a Collection detail page: ⋮ → Query this collection’s annotations
• On a DataObject detail page: ⋮ → Query this entity’s annotations

Either link appends ?focusAppId=<appId>&scope=collection|data-object so the query is seeded with a FILTER for that entity and the URL remains bookmarkable.

Run a query

1. Leave the Repository ID field set to internal (the default n10s-backed store that holds all annotations you create through the UI or the MCP tools).
2. Type or paste a SPARQL SELECT or ASK query into the editor.
3. Click Run query or press Ctrl+Enter.

Results appear below the editor:

• Table (default) — one column per projected variable. Click any column header to sort. Switch to JSON to see the raw SPARQL 1.1 JSON result set.
• ASK — shows true / false as a coloured badge.

Click Reset to restore the default example query.

Example queries

List all annotations on a specific DataObject

Replace <appId> with the DataObject’s appId (visible in the URL or in the Semantic Annotations panel on its detail page).

PREFIX schema: <https://schema.org/>

SELECT ?predicate ?object
WHERE {
  ?s schema:identifier "<appId>" .
  ?s ?predicate ?object .
}

Find all DataObjects annotated with a given term

PREFIX oa: <http://www.w3.org/ns/oa#>

SELECT ?subject ?value
WHERE {
  ?subject oa:hasBody ?value .
  FILTER(CONTAINS(STR(?value), "turbopump"))
}
LIMIT 50

Check whether a specific annotation exists (ASK)

ASK {
  ?s <urn:shepard:thermography:recordingType> "evaluation" .
}

Restrictions

Only SELECT and ASK are accepted. INSERT, DELETE, UPDATE, DROP, CLEAR, LOAD, and COPY are rejected by the server-side SparqlQueryValidator and return a 400 error. Use the annotation API or the MCP tools to write data.

Admin SPARQL access

The admin SPARQL panel at /admin#sparql-playground uses the same query engine and accepts the same syntax. It is restricted to instance-admin users and is intended for schema-level inspection rather than day-to-day annotation queries.

Troubleshooting

See also

• Annotating data with semantic tags
• Semantic annotations reference
• Browse vocabularies — find predicate IRIs to use in queries