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From "Jens Rantil" <jens.ran...@tink.se>
Subject Re: Empty cqlsh cells vs. null
Date Fri, 24 Oct 2014 11:38:19 GMT
> What do you mean by “cqlsh explicitely writes ‘null’ in those cells” ?  Are you
seing textual value “null” written in the cells ?




Just to clarify, I am seeing three types of output for an int field. It’s either:

 * Empty output. Nothing. Nil. Also ‘’.

 * An integer written in green. Regexp: [0-9]+

 * Explicitly ‘null’ written in red letters.




My question concerns what the difference between Empty output and ‘null’ is. I’m also
curious how my Datastax Java driver will handle this, but that’ll be my next quest, I guess.




Thanks,

Jens


———
Jens Rantil
Backend engineer
Tink AB

Email: jens.rantil@tink.se
Phone: +46 708 84 18 32
Web: www.tink.se

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On Thu, Oct 23, 2014 at 4:36 PM, DuyHai Doan <doanduyhai@gmail.com> wrote:

> Hello Jens
> What do you mean by "cqlsh explicitely writes 'null' in those cells" ?  Are
> you seing textual value "null" written in the cells ?
>  Null in CQL can have 2 meanings:
> 1. the column did not exist (or more precisely, has never been created)
> 2. the column did exist sometimes in the past (has been created) but then
> has been deleted (tombstones)
> On Thu, Oct 23, 2014 at 8:37 AM, Jens Rantil <jens.rantil@tink.se> wrote:
>>  Hi,
>>
>> Not sure this is a Datastax specific question to be asked elsewhere. In
>> that case, let me know.
>>
>> Anyway, I have populated a Cassandra table from DSE Hive. When I fire up
>> cqlsh and execute a SELECT against the table I have columns of INT type
>> that are empty. At first I thought these were null, but it turns out that
>> cqlsh explicitly writes "null" in those cells. What can I make of this? A
>> bug in Hive serialization to Cassandra?
>>
>> Cheers,
>> Jens
>>
>> —
>> Sent from Mailbox <https://www.dropbox.com/mailbox>
>>
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