Hi, That’s how I have done it in many occasions. Nowadays there is the possibility use Cassandra 3.0 and materialised views so that you don’t need to keep two tables up to date manually: http://www.datastax.com/dev/blog/new-in-cassandra-3-0-materialized-views <http://www.datastax.com/dev/blog/new-in-cassandra-3-0-materialized-views>
Hannu > On 17 Mar 2016, at 12:05, Bo Finnerup Madsen <bo.gunder...@gmail.com> wrote: > > Hi, > > We are pretty new to data modelling in cassandra, and are having a bit of a > challenge creating a model that caters both for queries and updates. > > Let me try to explain it using the users example from > http://www.datastax.com/dev/blog/basic-rules-of-cassandra-data-modeling > <http://www.datastax.com/dev/blog/basic-rules-of-cassandra-data-modeling> > > They define two tables used for reading users, one by username and one by > email. > --------------------------------------------------------------------- > CREATE TABLE users_by_username ( > username text PRIMARY KEY, > email text, > age int > ) > > CREATE TABLE users_by_email ( > email text PRIMARY KEY, > username text, > age int > ) > --------------------------------------------------------------------- > > Now lets pretend that we need to delete a user, and we are given a username > as a key. Would the correct procedure be: > 1) Read the email from users_by_username using the username as a key > 2) Delete from users_by_username using the username as a key > 3) Delete from users_by_email using the email as a key > > Or is there a smarter way of doing this? > > Yours sincerely, > Bo Madsen >
