title: Update single column in cassandra
body: <p>I have following cassandra column family:</p>
  
  <pre><code>create column family cfn
   with comparator = UTF8Type
   and key_validation_class = UUIDType
   and column_metadata =[
        {column_name:email, validation_class: UTF8Type,index_type: KEYS}
        {column_name:full_name, validation_class: UTF8Type}
   ];
  </code></pre>
  
  <p>I want to update "full_name" of given "email" but i don't know the row key i only have "email". How can i do that using hector thrift api?</p>
  
  <p>I know that i will have to insert a new column as there is no update kind of thing in cassandra. Will it be necessary to get row key before inserting new column for the same row?</p>