class ReferentialIntegrityTableEntry {

  void addSourceForQueries(final String queryId) {
    if (!sourceForQueries.add(queryId)) {
      throw new IllegalStateException("Already source for query: " + queryId);
    }
  }

    ReferentialIntegrityTableEntry();
  private  ReferentialIntegrityTableEntry(
      final Set<String> sourceForQueries,
      final Set<String> sinkForQueries
  );

}