Thanks a lot. I have started with the videos too..I will get back if I see any problem.
Best Regards, Sandeep Kalra On Tue, Mar 1, 2016 at 12:36 PM, Jonathan Haddad <j...@jonhaddad.com> wrote: > I'd do something like this: > > CREATE TABLE questions ( > question_id timeuuid primary key, > question text > ); > > CREATE TABLE answers ( > question_id timeuuid, > answer_id timeuuid, > answer text, > primary key(question_id, answer_id) > ); > > CREATE TABLE comments ( > answer_id timeuuid, > comment_id timeuuid, > comment text, > primary key(question_id, answer_id) > ); > > You can select all the answers for a given question (ordered by the time > they appeared, yay) with : > SELECT * from answers where question_id = ? > > Same applies to comments. > > If you want to do categories as well, you'd want to modify the question > table to have category_id as the partition key. Again, I suggest you watch > the videos in Datastax Academy and not try to shortcut your data modeling > knowledge as it's really, really important and screwing it up will cost you > 100x the time as well as about a million headaches. > > On Tue, Mar 1, 2016 at 9:59 AM Sandeep Kalra <sandeep.ka...@gmail.com> > wrote: > >> I do not have limit of number of Answers or its comments. Assume it to >> be clone of StackOverflow.. >> >> >> >> Best Regards, >> Sandeep Kalra >> >> >> On Tue, Mar 1, 2016 at 11:29 AM, Jack Krupansky <jack.krupan...@gmail.com >> > wrote: >> >>> Clustering columns are your friends. >>> >>> But the first question is how you need to query the data. Queries drive >>> data models in Cassandra. >>> >>> What is the cardinality of this data - how many answers per question and >>> how many comments per answer? >>> >>> >>> -- Jack Krupansky >>> >>> On Tue, Mar 1, 2016 at 12:23 PM, Sandeep Kalra <sandeep.ka...@gmail.com> >>> wrote: >>> >>>> Hi all. >>>> >>>> I am beginner in Cassandra. >>>> >>>> I am working on Q&A project where I have to maintain a list of list for >>>> objects. >>>> >>>> For e.g. A Question can have list of Answers, and each Answer can then >>>> have list of Comments. >>>> >>>> -- >>>> As of now I have 3 tables. Questions, Answers, and Comments. I have >>>> stored UID of Answers in List<uid of answers> for question, and then each >>>> answer has List<UID of comments> in separate table. [Optionally a Comment >>>> may have replies] >>>> >>>> I do multiple queries to find the complete answers-list and then its >>>> related comments. >>>> >>>> This whole thing looks inefficient to me. >>>> -- >>>> >>>> Question: >>>> *Is there a better way to do it in Cassandra*. What can I do as far as >>>> re-designing database to have lesser queries. >>>> >>>> >>>> >>>> Best Regards, >>>> Sandeep Kalra >>>> >>>> >>> >>
