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From Michal Michalski <mich...@opera.com>
Subject Re: NULL values
Date Wed, 27 Feb 2013 10:15:22 GMT
W dniu 27.02.2013 10:57, Marco Matarazzo pisze:> You may also be 
interested in this:
 >
 > https://issues.apache.org/jira/browse/CASSANDRA-3783

CASSANDRA-3783 might not be the case here. The question is about using 
null in SELECT statements, which will require modifications in secondary 
indexes code, which is unlikely to be done now/soon (see Sylvain's 
comments in CASSANDRA-3783 and CASSANDRA-5081) and probably will be left 
to a follow-up ticket, while CASSANDRA-3783 will focus on INSERT/UPDATE 
statements (which would be very usefull together with prepared 
statements [CASSANDRA-5081]).

M.


>
> Also, I *guess* that a deleted column takes some (very small?) space with its tombstone,
until it's removed. But I leave the details to someone else, as I'm definitely not an expert.
>
>
> Il giorno 27/feb/2013, alle ore 10:35, Alain RODRIGUEZ <arodrime@gmail.com> ha
scritto:
>
>> Cassandra (C*) has no NULL values. C* is column schemaless, meaning you can have
different columns on each row of the same ColumnFamily (CF).
>>
>> So if you want to check if a certain column is NULL for a row, you just check if
it exist. By the way, you can store a column with a name and no value (empty value). This
empty value doesn't take any disk space AFAIK.
>>
>> About the TTL, their point is precisely to keep them for a predefined time. C* delete
them on without any action needed by a client, it's an internal work.
>>
>> Alain
>>
>>
>> 2013/2/27 Sloot, Hans-Peter <hans-peter.sloot@atos.net>
>> Hi,
>>
>>
>> How does Cassandra handle NULL values?
>>
>> I want to know how I can see rows where a certain column has no values.
>>
>>
>> For example if I set the TTL for columns is it possible to select rows where the
ttl has expired for deletion.
>>
>>
>> Regards Hans-Peter
>>
>>
>>
>>
>>
>>
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>
> --
> Marco Matarazzo
> == Hex Keep ==
>
> W: http://www.hexkeep.com
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> E: marco.matarazzo@hexkeep.com
>
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