Consider trying… UserTimeline CF
row_key: <user_id> column_names: <timestamp, other_user_id, action> column_values: action details To get the changes between two times specify the start and end timestamps and do not include the other components of the column name. e.g. from <1234, NULL, NULL> to <6789, NULL, NULL> Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 30/08/2012, at 11:32 PM, Morgan Segalis <msega...@gmail.com> wrote: > Sorry for the scheme that has not keep the right tabulation for some people... > Here's a space-version instead of a tabulation. > > user1 row : | lte | > lte -1 | lte -2 | > lte -3 | lte -4 | > values : | user2-name-change | user3-pic-change | > user4-status-change | user2-pic-change | user2-status-change | > > If for example, user2 changes it's picture, the row should look like that : > > user1 row : | lte | > lte -1 | lte -2 | > lte -3 | lte -4 | > values : | user2-pic-change | user2-name-change > | user3-pic-change | user4-status-change | user2-status-change | > > Le 30 août 2012 à 13:22, Morgan Segalis a écrit : > >> Hi everyone, >> >> I'm trying to use cassandra in order to store a "timeline", but with values >> that must be unique (replaced). (So not really a timeline, but didn't find a >> better word for it) >> >> Let's me give you an example : >> >> - An user have a list of friends >> - Friends can change their nickname, status, profile picture, etc... >> >> at the beginning the CF will look like that for user1: >> >> lte = latest-timestamp-entry, which is the timestamp of the entry (-1 -2 -3 >> means that the timestamp are older) >> >> user1 row : | lte | >> lte -1 | lte -2 | lte >> -3 | lte -4 | >> values : | user2-name-change | user3-pic-change >> | user4-status-change | user2-pic-change | user2-status-change | >> >> If for example, user2 changes it's picture, the row should look like that : >> >> user1 row : | lte | >> lte -1 | lte -2 | lte >> -3 | lte -4 | >> values : | user2-pic-change | >> user2-name-change | user3-pic-change | user4-status-change | >> user2-status-change | >> >> notice that user2-pic-change in the first representation (lte -3) has >> "moved" to the (lte) on the second representation. >> >> That way when user1 connects again, It can retrieve only informations that >> occurred between the last time he connected. >> >> e.g. : if the user1's last connexion date it between "lte -2" and "lte -3", >> then he will only be notified that : >> >> - user2 has changed his picture >> - user2 has changed his name >> - user3 has changed his picture >> >> I would not keep the old data since the "timeline" is saved locally on the >> client, and not on the server. >> I really would like not to search for each column in order to find the >> "user2-pic-change", that can be long especially if the user has many friends. >> >> Is there a simple way to do that with cassandra, or I am bound to create >> another CF, with column title holding the action e.g. "user2-pic-change" and >> for value the timestamp when it appears ? >> >> Thanks, >> >> Morgan. >> >
