Expiring data with time-to-live (TTL) example
Use the INSERT and UPDATE commands for setting the expire time (TTL) for data in a column.
Both the INSERT and UPDATE commands support setting
                a time for data in a column to expire. Use CQL to set the expiration time
                    (TTL).
Procedure
- 
                Use the INSERTcommand to set a calendar listing in the calendar table to expire in 86400 seconds (one day).INSERT INTO cycling.calendar ( race_id, race_name, race_start_date, race_end_date ) VALUES ( 200, 'placeholder', '2015-05-27', '2015-05-27' ) USING TTL 86400; 
- 
                Extend the expiration period to three days (259200 seconds) by using the
                    UPDATEcommand with theUSING TTLkeyword. Also set the race name.UPDATE cycling.calendar USING TTL 259200 SET race_name = 'Tour de France - Stage 12' WHERE race_id = 200 AND race_start_date = '2015-05-27' AND race_end_date = '2015-05-27'; 
- 
                Delete a column's existing TTL by setting its value to zero.
                UPDATE cycling.calendar USING TTL 0 SET race_name = 'Tour de France - Stage 12' WHERE race_id = 200 AND race_start_date = '2015-05-27' AND race_end_date = '2015-05-27'; You can set a default TTL for an entire table by setting the table's default_time_to_live property. Setting TTL on a column using the INSERT or UPDATE command overrides the table TTL. 
