title: Why doesn't my Cassandra update work?
body: <p>I have the following Cassandra table:</p>
  
  <p><code>create table start_stop (id text, start text, end text, price double, PRIMARY KEY (id, start));</code></p>
  
  <p>I do an insert like this:</p>
  
  <p><code>insert into start_stop (id, start) values ('123', 'w');</code></p>
  
  <p>Now I want to do an update:</p>
  
  <p><code>update start_stop set end = 'z' where id = '123';</code></p>
  
  <p>and I get an error:
  <code>InvalidRequest: code=2200 [Invalid query] message="Some clustering keys are missing: start"</code></p>
  
  <p>How can I fix this, aside from doing a query to look up the start value before doing an update?</p>