Pre-Migration Cleanup: Root User References

Problem

Some projects have resources where knora-base:attachedToUser references the root user (username root). The root user must never be imported into another DSP instance. The project migration import fails if admin.nq contains the root user, whether the root user already exists on the target instance or not.

Detection

When exporting a project, the export service logs a warning if the root user is referenced. Search the export logs for the following pattern:

Export includes root user 'http://rdfh.ch/users/...' Resources referencing root require pre-migration cleanup before import.

Cleanup Procedure

For each affected project, run the following SPARQL UPDATE to reassign resources from the root user to a designated project user. Replace the placeholders with actual values.

PREFIX knora-base: <http://www.knora.org/ontology/knora-base#>

DELETE {
  GRAPH ?g {
    ?resource knora-base:attachedToUser <ROOT_USER_IRI> .
  }
}
INSERT {
  GRAPH ?g {
    ?resource knora-base:attachedToUser <DESIGNATED_USER_IRI> .
  }
}
WHERE {
  GRAPH ?g {
    ?resource knora-base:attachedToUser <ROOT_USER_IRI> .
  }
  FILTER(STRSTARTS(STR(?g), "http://www.knora.org/data/SHORTCODE/"))
}

Replace:

• ROOT_USER_IRI with the root user's IRI (e.g., http://rdfh.ch/users/root)
• DESIGNATED_USER_IRI with a project member's IRI who should be the new owner
• SHORTCODE with the project's shortcode (e.g., 0110)

Notes

• This is a one-time manual step per project.
• Choose a designated user who is an active project member.
• The cleanup modifies the source instance's data — run it before exporting.
• Built-in users (SystemUser, AnonymousUser) do not need cleanup. Their triples are automatically stripped during import.