Return-Path: X-Original-To: apmail-cassandra-user-archive@www.apache.org Delivered-To: apmail-cassandra-user-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 326D8E448 for ; Wed, 27 Feb 2013 09:36:19 +0000 (UTC) Received: (qmail 63167 invoked by uid 500); 27 Feb 2013 09:36:16 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 63014 invoked by uid 500); 27 Feb 2013 09:36:16 -0000 Mailing-List: contact user-help@cassandra.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@cassandra.apache.org Delivered-To: mailing list user@cassandra.apache.org Received: (qmail 62992 invoked by uid 99); 27 Feb 2013 09:36:15 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 27 Feb 2013 09:36:15 +0000 X-ASF-Spam-Status: No, hits=1.5 required=5.0 tests=HTML_MESSAGE,RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of arodrime@gmail.com designates 209.85.217.171 as permitted sender) Received: from [209.85.217.171] (HELO mail-lb0-f171.google.com) (209.85.217.171) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 27 Feb 2013 09:36:08 +0000 Received: by mail-lb0-f171.google.com with SMTP id gg13so339135lbb.30 for ; Wed, 27 Feb 2013 01:35:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:mime-version:in-reply-to:references:from:date:message-id :subject:to:content-type; bh=BPS/k+n87hTJBNcaX98hUgAuVIJYqt3VC+6VU25Y2dI=; b=EZEpWNGOXzHHRCz3/eHgJSxGzIGJNd9KTEEU0gCVwJRH5H/sXjVU8CrpJ9cu2x4i4X LV3aG+bJdWnhJNoqTIYig4rLbRbpphYnN0Ppl9GKTLOZPxZxOReKeERfQRcjFZ7d5HMN bZ9rJtFghJCNGZRcqbEEBXmhs2gCNwE1uteR8orYJUvXeuFcBB0cpDqnKs49z+21SVVj radnWoEpXJjRyJDjegC9e9rWvri17s44F2HfTNAwcXcswwxiVs4fIdEfzykV4tVUosXY fFp1bh4ORrdIUrlnlVwbFht3on+5vUT169TvnaAvfvps0OA/nxCCZJh8uGS0PMiD5iqp Jkig== X-Received: by 10.152.47.242 with SMTP id g18mr1326196lan.42.1361957747051; Wed, 27 Feb 2013 01:35:47 -0800 (PST) MIME-Version: 1.0 Received: by 10.112.44.230 with HTTP; Wed, 27 Feb 2013 01:35:26 -0800 (PST) In-Reply-To: References: From: Alain RODRIGUEZ Date: Wed, 27 Feb 2013 10:35:26 +0100 Message-ID: Subject: Re: NULL values To: user@cassandra.apache.org Content-Type: multipart/alternative; boundary=bcaec5540422b6526204d6b17f78 X-Virus-Checked: Checked by ClamAV on apache.org --bcaec5540422b6526204d6b17f78 Content-Type: text/plain; charset=ISO-8859-1 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 > 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 > > > > > > > Dit bericht is vertrouwelijk en kan geheime informatie bevatten enkel > bestemd voor de geadresseerde. Indien dit bericht niet voor u is bestemd, > verzoeken wij u dit onmiddellijk aan ons te melden en het bericht te > vernietigen. Aangezien de integriteit van het bericht niet veilig gesteld > is middels verzending via internet, kan Atos Nederland B.V. niet > aansprakelijk worden gehouden voor de inhoud daarvan. Hoewel wij ons > inspannen een virusvrij netwerk te hanteren, geven wij geen enkele garantie > dat dit bericht virusvrij is, noch aanvaarden wij enige aansprakelijkheid > voor de mogelijke aanwezigheid van een virus in dit bericht. Op al onze > rechtsverhoudingen, aanbiedingen en overeenkomsten waaronder Atos Nederland > B.V. goederen en/of diensten levert zijn met uitsluiting van alle andere > voorwaarden de Leveringsvoorwaarden van Atos Nederland B.V. van toepassing. > Deze worden u op aanvraag direct kosteloos toegezonden. > > This e-mail and the documents attached are confidential and intended > solely for the addressee; it may also be privileged. If you receive this > e-mail in error, please notify the sender immediately and destroy it. As > its integrity cannot be secured on the Internet, the Atos Nederland B.V. > group liability cannot be triggered for the message content. Although the > sender endeavours to maintain a computer virus-free network, the sender > does not warrant that this transmission is virus-free and will not be > liable for any damages resulting from any virus transmitted. On all offers > and agreements under which Atos Nederland B.V. supplies goods and/or > services of whatever nature, the Terms of Delivery from Atos Nederland B.V. > exclusively apply. The Terms of Delivery shall be promptly submitted to you > on your request. > > Atos Nederland B.V. / Utrecht > KvK Utrecht 30132762 > --bcaec5540422b6526204d6b17f78 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
Cassandra (C*) has no NULL values. C* is column schemaless= , meaning you can have different columns on each row of the same ColumnFami= ly (CF).

So if you want to check if a certain colu= mn 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= 9;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 neede= d by a client, it's an internal work.

Alain


2013/2/27 Sloot, Hans-Peter <hans-peter.sloot@atos.net>=

Hi,=

=A0=

How does C= assandra handle NULL values?

I want to = know how I can see rows where a certain column has no values.

=A0=

For exampl= e if I set the TTL for columns is it possible to select rows where the ttl = has expired for deletion.

=A0=

Regards Ha= ns-Peter






Dit bericht is vertrouwelijk en kan geheime informatie bevatten enkel beste= md voor de geadresseerde. Indien dit bericht niet voor u is bestemd, verzoe= ken wij u dit onmiddellijk aan ons te melden en het bericht te vernietigen.= Aangezien de integriteit van het bericht niet veilig gesteld is middels verzending via internet, kan Atos N= ederland B.V. niet aansprakelijk worden gehouden voor de inhoud daarvan. Ho= ewel wij ons inspannen een virusvrij netwerk te hanteren, geven wij geen en= kele garantie dat dit bericht virusvrij is, noch aanvaarden wij enige aansprakelijkheid voor de mogelijke aanwezig= heid van een virus in dit bericht. Op al onze rechtsverhoudingen, aanbiedin= gen en overeenkomsten waaronder Atos Nederland B.V. goederen en/of diensten= levert zijn met uitsluiting van alle andere voorwaarden de Leveringsvoorwaarden van Atos Nederland B.V. va= n toepassing. Deze worden u op aanvraag direct kosteloos toegezonden.

This e-mail and the documents attached are confidential and intended solely= for the addressee; it may also be privileged. If you receive this e-mail i= n error, please notify the sender immediately and destroy it. As its integr= ity cannot be secured on the Internet, the Atos Nederland B.V. group liability cannot be triggered for the messag= e content. Although the sender endeavours to maintain a computer virus-free= network, the sender does not warrant that this transmission is virus-free = and will not be liable for any damages resulting from any virus transmitted. On all offers and agreements under w= hich Atos Nederland B.V. supplies goods and/or services of whatever nature,= the Terms of Delivery from Atos Nederland B.V. exclusively apply. The Term= s of Delivery shall be promptly submitted to you on your request.

Atos Nederland B.V. / Utrecht
KvK Utrecht 30132762


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