@Test
  public void testRelations() throws SqlJetException, IOException {
    SetMultimap<String, String> gene2diseases = HashMultimap.create();
    for (String gene : table.rowKeySet()) {
      gene2diseases.putAll(gene, table.row(gene).keySet());
    }
    List<String> entryStrings = Lists.newArrayList();
    for (Entry<String, String> e : gene2diseases.entries()) {
      entryStrings.add(e.getKey() + "\t" + e.getValue());
    }
    String relationString = Joiner.on('\n').join(entryStrings);
    Files.write(relationString, new File("result/disgenet-relations.txt"), Charsets.UTF_8);
  }