Using a counter

A counter is a special column for storing a number that is updated by increments or decrements.

To load data into a counter column, or to increase or decrease the value of the counter, use the UPDATE command. Apache Cassandra rejects USING TIMESTAMP or USING TTL in the command to update a counter column.

Procedure

Create a table for the counter column.

CREATE TABLE IF NOT EXISTS cycling.popular_count (
  id UUID PRIMARY KEY,
  popularity counter
);

Loading data into a counter column is different than other tables. The data is updated rather than inserted.

BEGIN COUNTER BATCH

  UPDATE cycling.popular_count
  SET popularity = popularity + 1
  WHERE id = 6ab09bec-e68e-48d9-a5f8-97e6fb4c9b47;

  UPDATE cycling.popular_count
  SET popularity = popularity + 125
  WHERE id = 6ab09bec-e68e-48d9-a5f8-97e6fb4c9b47;

  UPDATE cycling.popular_count
  SET popularity = popularity - 64
  WHERE id = 6ab09bec-e68e-48d9-a5f8-97e6fb4c9b47;

APPLY BATCH;

UPDATE cycling.popular_count
SET popularity = popularity + 2
WHERE id = 6ab09bec-e68e-48d9-a5f8-97e6fb4c9b47;

The popularity column has a value of 64.

CQL
Result

SELECT *
FROM cycling.popular_count;

bplist00�XUTI-Data�_$com.apple.traditional-mac-plain-text_public.utf8-plain-text_public.utf16-plain-textO*select_all_from_popular_count.results copy_*select_all_from_popular_count.results copyOTselect_all_from_popular_count.results copyB[u��	&

Additional increments or decrements changes the value of the counter column.

Cassandra Documentation

Version:

Using a counter

Procedure