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From Kalpana Suraesh <ks4...@gmail.com>
Subject Re: deleting columns with CAS (2.0.0-beta2)
Date Mon, 29 Jul 2013 20:11:31 GMT
Yep, for example, I created a simple users table and then issued a delete
with an IF statement. i.e

CREATE TABLE users (
         user_name varchar,
         password varchar,
         state varchar,
         PRIMARY KEY (user_name)
       );
INSERT INTO users
         (user_name, password, state)
         VALUES ('jsmith', 'ch@ngem3a', 'alive');
DELETE password FROM users WHERE user_name = 'jsmith' IF state = 'alive';

And note that the delete won't go through if the state is something else,
i.e. 'dead', as expected.


On Mon, Jul 29, 2013 at 12:58 AM, aaron morton <aaron@thelastpickle.com>wrote:

> > I presume it can be done because conditional deletes work through CQL3.
> Out of interest where do you have an example or a reference for this?
>
> Cheers
>
> -----------------
> Aaron Morton
> Cassandra Consultant
> New Zealand
>
> @aaronmorton
> http://www.thelastpickle.com
>
> On 26/07/2013, at 8:07 AM, Kalpana Suraesh <ks4001@gmail.com> wrote:
>
> > Hi,
> >
> > I've been playing around with CAS (compare-and-swap) in the 2.0 beta,
> using the Thrift API. I can't at all figure out how to delete columns while
> using CAS, however. I'm able to update/insert columns by adding them to the
> list of updates that is passed as a parameter to
> org.apache.cassandra.thrift.Cassandra.Client#cas(). But there seems to be
> no indication as to how to delete.
> >
> > I presume it can be done because conditional deletes work through CQL3.
> However, I'm interested in using Hector/Java (particularly as CQL3 does not
> yet allow batched conditional statements).
> >
> > Any help would be great!
> >
> > Thanks,
> > Kalpana
>
>


-- 
--
Kalpana Suraesh

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