Denormalize your data to support the query, e.g.: CREATE TABLE name_by_cust_id (cust_id int, name text, PRIMARY KEY > (cust_id)); > SELECT name WHERE cust_id = 3;
For additional queries, similarly denormalize. Refer to https://academy.datastax.com/courses for free online courses covering this thoroughly. On Sun, Sep 6, 2015 at 2:59 PM, ssaitalatech <ssaitalat...@gmail.com> wrote: > > > > Sent from Samsung Mobile. > > > > > > 1. Hi All, > > > > 1. I am trying to model RDBMS joins into cassandra. As I am new to > cassandra, I need your help/suggestion on this. Below is the information > regarding the query: > 2. > 3. I have a query in RDBMS as follows: > 4. > 5. select t3.name from Table1 t1, Table2 t2, Table3 t3, Table4 t4 > where > 6. t2.cust_id = 3 and t4.sid = t1.sid and t1.colid = t2.colid and > t4.cid = t3.cid > 7. > 8. > 9. Now, trying to make a shimilar query in cassandra: > 10. > 11. As per my learning experience in Cassandra, I got the below 2 > solutions: (as cassandra does not support joins) > 12. > 13. ****Solution 1:***** > 14. > 15. 1) Fetch all the records with t2.cust_id = 3 > 16. 2) Now again run another query that will do the condition t3.sid = > t1.sid on the results returned from point 1. > 17. 3) continue the same for all the conditions. > 18. > 19. Drawbacks with this approach: > 20. > 21. For each join, I have to do a network call to fetch the details. > Also, it will take more time..as I am running multiple conditions > 22. > 23. > 24. ****Solution 2: ***** > 25. > 26. 1) Create a map table for every possible join. > 27. > 28. Drawbacks with this aproach: > 29. > 30. I think, this is not a right approach. So join to table (map > table) mapping idea is not right. > 31. > 32. pastebin link for the same: http://pastebin.com/FRAyihPT > 33. Please suggest me on this. > > > >
