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From Kalpana Suraesh <ks4...@gmail.com>
Subject Re: deleting columns with CAS (2.0.0-beta2)
Date Wed, 31 Jul 2013 17:42:46 GMT
Actually, it was pointed out to me that there's a comment in
org.apache.cassandra.service.StorageProxy#cas() that says:

            // finish the paxos round w/ the desired updates
            // TODO turn null updates into delete?
            Commit proposal = Commit.newProposal(key, ballot, updates);

so it looks like the deletes I wanted have not been implemented yet. I'd be
interested to know if there's a bug that I can track for this, though.

Thanks,
Kalpana


On Mon, Jul 29, 2013 at 1:11 PM, Kalpana Suraesh <ks4001@gmail.com> wrote:

> 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
>



-- 
--
Kalpana Suraesh

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