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From Peter Tillotson <slatem...@yahoo.co.uk>
Subject Re: Java bits: Horizontal Scalibility and DAO layer design
Date Wed, 27 Jul 2011 19:41:03 GMT
I had a quick look at DAO and my common uses case is, row names
appearing as column ID's elsewhere (indexes etc). I also wanted to track
deltas at a column level and have a reasonable sized client side cache.

I ended up with two abastract DAO's, one for Column Family, one for
Super column factory, then subclasses with overridden methods for build
/ deconstruct POJOs.

Managing a bag of columns in this way makes column level locking easy,
and the delta approach minimizes the network traffic.


On 27/07/11 16:15, Selcuk Bozdag wrote:
> Hi,
> 
> The question I am asking is a bit about the design of a data access
> objects layer on top of a cassandra datastore.
> 
> I had a look at project Kundera which basically implies JPA approach
> by creating POJOs and mapping them through annotations. Looks
> promising but what if I would like to have new columns inside the data
> store(i.e. an attribute of a pojo class) without changing the
> codebase? How could I achieve such an extensiblity on the DAO layer?
> What would be the most relevant design pattern?
> 
> Please do not take the question regarding Kundera, it was just an
> example. The eventual design should let me CRUD POJOs while gaining an
> ability to be extended.
> 
> Regards,
> 
> Selcuk
> 


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