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From Chen Xinli <chen.d...@gmail.com>
Subject Re: kundera: Open source JPA 1.0 compliant ORM for Cassandra
Date Thu, 19 Aug 2010 14:32:26 GMT
I have a question about lucandra: the row-ids from reversed-index is
computed in cassandra , or using a client to get reversed index first and
computed in client machine?

2010/8/19 Animesh Kumar <animesh.kumar@impetus.co.in>

> Hi Jonathan,
>
> Glad that you liked the effort. Kundera team is constantly watching
> Cassandra developments to pick features up as soon as they become available,
> for example, secondary indexes, schema generator support etc.
>
> I would like to highlight few important stuffs about Kundera:
>
> 1. Kundera has been architected so as to be able to use any existing
> Cassandra client library, Hector, Pelops whatever, in simple adaptor design
> format. Kundera though supports Pelops only, however should anyone want to
> write a custom adaptor for any of his favorite client libraries he can
> easily do it.
>
> 2. Kundera - for now - uses Lucandra to store reverse-indexes into
> Cassandra itself. Support for Solr will be introduced very soon.
>
> 3. Kundera supports JPA defined relationships like, OneToOne, OneToMany,
> ManyToOne and ManyToMany between concrete entity objects with full Cascade
> support and Lazy/Eager loading strategies. This is achieved by storing
> foreign row-ids into holding entity's CF row. Kundera doesn't support entity
> embedding or entity inheritance yet, but they are in pipeline.
>
> 4. Kundera converts JPA queries to Lucene queries which run on Lucene
> indexes to fetch row-ids which are used to look-up data from Cassandra CFs.
> You can also directly execute Lucene queries.
>
> This might have given you a better picture of Kundera, should you need more
> information you can visit: http://kundera.googlecode.com
>
> Thanks,
> Animesh
> iLabs, Impetus
>
>
>
> -----Original Message-----
> From: Jonathan Ellis [mailto:jbellis@gmail.com]
> Sent: Sunday, August 01, 2010 11:01 PM
> To: user@cassandra.apache.org
> Subject: Re: kundera: Open source JPA 1.0 compliant ORM for Cassandra
>
> Glad to see this, and I hope you'll be able to take advantage of the
> secondary index features coming in 0.7.
>
> Supporting different lower-level "drivers" seems like wasted effort to me,
> fwiw.
>
> On Sat, Jul 31, 2010 at 8:54 AM, Sanjay Sharma
> <sanjay.sharma@impetus.co.in> wrote:
> > Hi All,
> >
> > We are happy to announce and share a new ORM over Cassandra - kundera
> >
> > The project is Apache licensed and hosted at
> http://kundera.googlecode.com
> >
> >
> >
> > The project uses custom Cassandra Annotations and is fully JPA 1.0
> > compliant. @ColumnFamily and @SuperColumnFamily are the main Cassandra
> > specific annotations.
> >
> >
> >
> > Search/Indexing is automatically included by using "Lucandra" and drives
> the
> > JPA-QL query support. Use of Lucandra also enables users to write Lucene
> > queries along with JPA-QL queries.
> >
> >
> >
> > As per the main author of kundera - Animesh -" The idea behind Kundera is
> to
> > make working with Cassandra drop-dead simple and fun. Kundera does not
> > reinvent the wheel by making another client library; rather it leverages
> the
> > existing libraries and builds - on top of them - a wrap-around API to
> help
> > developers do away with unnecessary boiler plate codes, and program a
> > neater-and-cleaner code that reduces code-complexity and improves
> quality.
> > And above all, improves productivity."
> >
> >
> >
> > The current implementation uses the versatile "Pelops" library as the
> > underlying client API and plans are to add support for Hector and Thrift
> > clients as well.
> >
> >
> >
> > Here is a sample kundera Entity bean -
> >
> > @Entity
> >
> > @ColumnFamily(keyspace = "Keyspace1", family = "SimpleComment")
> >
> > public class SimpleComment {
> >
> >     @Id
> >
> >     private String id;
> >
> >     @Column(name = "userId")
> >
> >     private String userId;
> >
> >     @Column(name = "comment")
> >
> >     private String commentText;
> >
> >
> >
> >     ......
> >
> > }
> >
> > JPA queries are as simple as-
> >
> >         Query query = entityManager.createQuery("SELECT c from
> SimpleComment
> > c where userId='me'");
> >
> >         List<SimpleComment> list = query.getResultList();
> >
> >
> >
> > There is already support for Spring based persistence integration like
> the
> > good old Spring+Hibernate integration and is as simple as this-
> >
> >     <bean id="entityManagerFactory"
> >
> class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
> >
> >         <property name="persistenceUnitName" value="myPersistenceUnit"/>
> >
> >                 </bean>
> >
> > More examples are available in kundera's wiki and Animesh's blogs. The
> > spring integration example is here
> >
> >
> >
> > Regards,
> >
> > Sanjay Sharma
> >
> > iLabs, Impetus
> >
> > ________________________________
> > Impetus is sponsoring 'Hadoop India User Group Meet Up'- a technology
> > un-conference on July 31, 2010 at Impetus Office, Noida. The event will
> shed
> > light on Hadoop technology and channelized efforts to develop an active
> > Hadoop community.
> >
> > Click http://www.impetus.com/ to know more. Follow our updates on
> > www.twitter.com/impetuscalling .
> >
> >
> > NOTE: This message may contain information that is confidential,
> > proprietary, privileged or otherwise protected by law. The message is
> > intended solely for the named addressee. If received in error, please
> > destroy and notify the sender. Any use of this email is prohibited when
> > received in error. Impetus does not represent, warrant and/or guarantee,
> > that the integrity of this communication has been maintained nor that the
> > communication is free of errors, virus, interception or interference.
> >
>
>
>
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of Riptano, the source for professional Cassandra support
> http://riptano.com
>
> Impetus is sponsoring 'Hadoop India User Group Meet Up'- a technology
> un-conference on July 31, 2010 at Impetus Office, Noida. The event will shed
> light on Hadoop technology and channelized efforts to develop an active
> Hadoop community.
>
> Click http://www.impetus.com/ to know more. Follow our updates on
> www.twitter.com/impetuscalling .
>
>
> NOTE: This message may contain information that is confidential,
> proprietary, privileged or otherwise protected by law. The message is
> intended solely for the named addressee. If received in error, please
> destroy and notify the sender. Any use of this email is prohibited when
> received in error. Impetus does not represent, warrant and/or guarantee,
> that the integrity of this communication has been maintained nor that the
> communication is free of errors, virus, interception or interference.
>



-- 
Best Regards,
Chen Xinli

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