Cassandra - Partition Key, Clustering key

Partition Key: It will be hashed and saved across nodes.\
Clustering Key: It will group in the same partition key.

PRIMARY KEY((partion key), clustering key)\
Example)\
create table User(\
email text,\
name text,\
desc text,\
user_id uuid\
PRIMARY KEY((email), name, user_id)\
) WITH CLUSTERING ORDER BY (name DESC, user_id ASC);

Primary Key: email\
Clustering Key: name, user_id

Reason of adding a user_id is to ensure the uniqueness of primary key.