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From bujji <sivait...@gmail.com>
Subject Re: Data from multiple tables (Join Data)
Date Tue, 20 Jul 2010 07:19:46 GMT
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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