CQL improvements in Cassandra 2.0

Cassandra 2.0 introduces several enhancements to the CQL front, including the ability to drop columns and support for lightweight transactions using IF keyword in INSERT, UPDATE, and DELETE statements. It also offers conditional schema modification statements and experimental support for triggers. Secondary indexing is now allowed on non-primary key CQL3 columns, but not yet on collection columns. Additionally, Cassandra 2.0 introduces the second version of its native protocol for CQL, which brings improvements over the first version.