Learning Apache Cassandra

Collection columns and concurrent updates

Happily, Cassandra's collection columns allow us to bypass the entire read-mutate-write process, allowing us to express the exact operation we want to do in CQL without regard to the current value of the column.

Defining collection columns

Given the limitations of the serialized approach, let's drop our text column and replace it with a collection column of the same name. Cassandra offers three flavors of collections: lists, sets, and maps. We'll explore all three in this chapter, starting with a set column, which is the most appropriate for our starred_by_users column:

ALTER TABLE "user_status_updates"
DROP "starred_by_users";

ALTER TABLE "user_status_updates"
ADD "starred_by_users" SET<text>;

The last line ...