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From Marco Matarazzo <marco.matara...@hexkeep.com>
Subject Re: NULL values
Date Wed, 27 Feb 2013 09:57:39 GMT
You may also be interested in this: 

https://issues.apache.org/jira/browse/CASSANDRA-3783


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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