Re: deleting columns with CAS (2.0.0-beta2)
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 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 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 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
Re: deleting columns with CAS (2.0.0-beta2)
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 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 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
deleting columns with CAS (2.0.0-beta2)
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
