title: How to code in reactor to update a specific field in a cassandra DB record
body: <p>I am using ReactiveCassandraRepository and I can create new record as below.</p>
  
  <pre><code>public Mono&lt;String&gt; saveAbc(Abc toBeSaved) {
      return abcRepository.save(toBeSaved).map(saved -&gt; saved.getId());
  }
  </code></pre>
  
  <p>But I could not imagine how to update a specific field in a DB record since 2 reactive operations (findById &amp; save) are involved.</p>
  
  <p>I wrote a code as below to create or update status if exists, but seems to be not working.</p>
  
  <pre><code>public Mono&lt;String&gt; saveAbc(Abc toBeSaved) {
      return abcRepository.findById(toBeSaved.getId())
          .map(current -&gt; abcRepository.save(transform(toBeSaved, current)).map(saved -&gt; saved.getId()))
          .flatMap(id -&gt; id);
  }
  
  private Abc transform(Abc toBeSaved, Abc current) {
      if(current == null) {
          return toBeSaved;
      } else {
          current.setStatus(toBeSaved.getStatus());
          return current;
      }
  }
  </code></pre>
  
  <p>Can someone please assist on that?</p>