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From aaron morton <aa...@thelastpickle.com>
Subject Re: Data from multiple tables (Join Data)
Date Tue, 20 Jul 2010 10:01:31 GMT
I'm not sure what your overload concern is. You either need to make multiple requests or de-normalise
so that your query can be resolved from one CF. There are no joins. 

Try it and see would be the best advice. You can always add more nodes to the cluster. 

Aaron



On 20 Jul 2010, at 19:19, bujji wrote:

> hi Aaron,
> 
> Thanks for your reply
> I can integrate some transaction mechanism with Cassandra so that i can do the transactions.
> 
> but is it possible to get data from more than one table without much overload and in
an efficient way ?
> give me some good example if possible...
> 
> Thanks,
> Visu
> 
> 
> On Tue, Jul 20, 2010 at 10:45 AM, Aaron Morton <aaron@thelastpickle.com> wrote:
> Cassandra may not be the best fit for a billing system. I'm guessing the lack of transactions
would be a problem if you want to update inventory levels.
> 
> If you want to get data from multiple column families you will need to make multiple
calls, or de-normalise the data so you can get all the data you need from one column family
for a single key. Such as storing the inventory data in the same column family as the product
info. Perhaps using a Super Column Family with a super column for the ProductData, another
for the Inventory etc. You could then read all the colums in the CF for one product and get
all the data you want without doing a join.
> 
> In general do-normalise to remove the need for joins. Also be aware of the transaction
guarantees you are giving up. 
> 
> Hope that helps. 
> Aaron
> 
> 
> On 20 Jul, 2010,at 04:03 PM, bujji <sivaits4u@gmail.com> wrote:
> 
>> Hi all,
>> 
>> I am new to Cassandra...
>> 
>> I want to use to cassandra for a billing system.
>> 
>> As I saw in many places that Joins won't work in BigTable implementation but i feel
i needed it for my App.
>> 
>> I am unable to get the data from multiple tables (columnFamilies) like products and
inventory
>> 
>> As I am trying to do some joins implementation but fails....
>> 
>> Can I do it without joins ?
>> 
>> Can anybody give me some good model to use for my application or any standard example

>> please help me folks,
>> 
>> Thanks ,
>> Bujji
> 


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