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From gabriele renzi <>
Subject Modeling question
Date Thu, 26 Nov 2009 08:52:30 GMT
hi everyone,

in my team, we are considering using cassandra for our project in
place of a (pseudo)relational solution, but I am not sure on how we
should handle a couple of modeling issues.
Basically, my problem is how to bring into cassandra a db where
elements are in the form <primary, secondary, attached data..> with
the pair <primary, secondary> is unique (think <node, node, arc
weight>) and we mostly do queries in the form
   select secondary, data from db where primary= x  ---- perfect fit
for cassandra

and in batch jobs we want to rewrite the whole thing _but_ using the
other key for lookup, akin to
 1. insert or update (primary, secondary, data) values (.. .. .. )  --
we can do this using the primary lookup
 2. delete from db where secondary = x and not in just inserted -- how
do we do this?

it is my understanding that cassandra does not support secondary
indexes so we would have to do a full scan to perform the #2
operation, or we should mantain the second index by ourselves indexed
on secondary and containing references to the primary.

Am I missing something? Sorry for the dumb question/faq but I am not
smart enough to shift my mental easily :)

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