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From: Jonathan Ellis <jbellis@gmail.com>
Date: Fri, 21 May 2010 18:07:34 -0700
Message-ID: <AANLkTinJkPeBQrlVMUIrPYl48zdCIjn7vjTBdvx3vgCl@mail.gmail.com>
Subject: Re: An ORM like plugin for Cassandra under Datanucleus
To: user@cassandra.apache.org
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Thanks!

You should probably add it to http://wiki.apache.org/cassandra/ClientOption=
s.

On Fri, May 21, 2010 at 12:22 PM, Pedro Gomes
<pedrogomes@lsd.di.uminho.pt> wrote:
> Hi all
> In the following weeks I have developed a plugin to the java persistence
> platform=A0Datanucleus,=A0similar to the one presented by Google for App =
Engine
> and a Hbase already present in the platform .
> Datanucleus:=A0http://www.datanucleus.org/project/download.html
> For now it allows the persistence of simples fields and one-one, one-many=
,
> and many-many relations, supporting collections and maps, arrays are next
> through the Java Data Objects (JDO) API.
> The platform allows a query language JDOQL, but I didn't add the support =
for
> it.
> You can access the project under :
> http://github.com/PedroGomes/datanucleus-cassandra
> Any feedback or doubts are welcome.
> I still have, though, some doubts on the implementation. To store many-ma=
ny,
> and one to many relations in Cassandra, i.e., one collection/map of point=
ers
> to other objects=A0I see two options:
> -The column, in the Column family class, correspondent to the relation
> contains a collection or map that codes the relation, i.e. it stores the =
ids
> to the objects,. This can be dangerous if the collection/map grows large.
> -You have a column family that codes relations, one simple Column family =
per
> relation, or a Super Column family that codes all relations . This approa=
ch
> however, =A0makes each fetch from the collection takes 3 read steps, but =
each
> object id is stored=A0separately.
> Other option that I'm thinking is a hybrid solution where the user choose=
s
> the pretended option.
> If someone can give some advice on this, I would be thankful.
> Grateful
> Pedro Gomes
>
>
>
>
>
>


--=20
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com