Comments on: Introduction to NOSQL and cassandra, part 2

By: Links about Apache Cassandra « Waltersf's Blog

Links about Apache Cassandra « Waltersf's Blog — Wed, 03 Mar 2010 21:37:32 +0000

[...] Links about Apache Cassandra Arquivado em: Uncategorized — Tags:cassandra, nosql — waltersf @ 9:37 pm Nice introduction about Cassandra Althought the video is in Hebrew, you can read the slides (in English). http://prettyprint.me/2010/01/20/introduction-to-nosql-and-cassandra-part-2/ [...]

By: Ran Tavory

Ran Tavory — Fri, 29 Jan 2010 07:24:13 +0000

Hi Mehar, one of the differences b/w SQL and Column oriented stores such as Cassandra is that you have to think very good when inserting your data, about how you’re going to retrieve it. Unlike SQL, in cassandra you only have primary keys, no secondary indexes. What you’re describing cannot simply be achieved in cassandra unless you plan for it ahead of time.
So if, for example, you create a CF Categories which is keyed by “Category1″ etc and holds the list of all records belonging to Category1 then that would be possible. But the usual case is that this scheme also calls for a lot of data denormalizations and repetition, so there’s a tradeoff.
You may also be interested in lazyboy, which sort of implements secondary indexes scheme over cassandra.

By: Mehar Chaitanya

Mehar Chaitanya — Fri, 29 Jan 2010 06:04:00 +0000

Hi Ran

I got some idea about cassandra after reading the above

We had some requirement like below

I have a table which has the columns like Category_name,Section_name,article,is_published_by with multiple records in the table.

I want to retrieve a query based on condition like belongs some category_name ‘X’ so then all values which belongs to X category will be retrieved along with other 3 columns

For E.g.,

select * from Table where category_name =’Category1′;

Here we are using category_name as key and retrieving all the records

Please let me know if it would be possible.

Can you please help me on this and kindly share your views.