Dropping a keyspace 

Remove a keyspace and all the database objects it contains.

Use the DROP KEYSPACE command to remove a keyspace along with all data and the database objects, such as tables, user defined functions, aggregates and types contained in the keyspace.

Note: When auto_snapshot is enabled in the cassandra.yaml, the keyspace is automatically backed up on the node where the command is executed. To manually backup the keyspace, see Taking a snapshot.

Procedure

Drop the keyspace.
DROP KEYSPACE keyspace_name;