Hi,
I want to use Cassandra for a new project, as you can guess I have a RDBMS
background however do not have any experience with NoSQL databases except
key/value pair in memory data grids/caches. (Oracle Coherence /Memcached.).
I'm trying to find out how do you perform queries with calculations on the fly
without inserting the data as calculated from the beginning.
Lets say we have latitude and longitude coordinates of all users and we have
Distance(from_lat, from_long, to_lat, to_long) function whichgives distance
between lat/longs pairs in kilometers.
Ex:user1_lat = 40 user1_long = 20user2_lat = 30 user3_long = 50
So, if we want to do same operation in regular RDBMS we can use this kind of
query to get users near to user_1's location.
* select user from users where Distance(40, 20, user.lat, user.long) = 5
How do we do this kind of operations in cassandra?
If we insert data as calculated from the beginning, lets say we have 1 million
users, then do we need to do 1 million insert operations for just updating 1
users coordinates? (Ofcourse no but then how?).
I believe huge complexity calculations are possible with Cassandra, but do not
know about querying out of accessing the data by it's key.
Thanks,
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