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Posted to user@cassandra.apache.org by Jeremiah Jordan <JE...@morningstar.com> on 2011/04/06 18:23:11 UTC
Secondary Index keeping track of column names
In 0.7.X is there a way to have an automatic secondary index
which keeps track of what keys contain a certain column? Right now we
are keeping track of this manually, so we can quickly get all of the
rows which contain a given column, it would be nice if it was automatic.
-Jeremiah
________________________________
Jeremiah Jordan
Application Developer
Morningstar, Inc.
Morningstar. Illuminating investing worldwide.
+1 312 696-6128 voice
jeremiah.jordan@morningstar.com
www.morningstar.com
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Re: Secondary Index keeping track of column names
Posted by Roland Gude <ro...@yoochoose.com>.
You could simulate it thoug. Just Add some Meta Column with a boolean Value indicating if the referred Column is in the Row or Not. Then Add an Index in that Meta Column and query for it.
I. E. Row a: (c=1234),(has_c=Yes)
Quert : List cf where has_c=Yes
Am 06.04.2011 um 18:52 schrieb "Jonathan Ellis" <jb...@gmail.com>:
> No, 0.7 indexes handle equality queries; you're basically asking for a
> IS NOT NULL query.
>
> On Wed, Apr 6, 2011 at 11:23 AM, Jeremiah Jordan
> <JE...@morningstar.com> wrote:
>> In 0.7.X is there a way to have an automatic secondary index
>> which keeps track of what keys contain a certain column? Right now we
>> are keeping track of this manually, so we can quickly get all of the
>> rows which contain a given column, it would be nice if it was automatic.
>>
>> -Jeremiah
>>
>> ________________________________
>> Jeremiah Jordan
>> Application Developer
>> Morningstar, Inc.
>>
>> Morningstar. Illuminating investing worldwide.
>>
>> +1 312 696-6128 voice
>> jeremiah.jordan@morningstar.com
>>
>> www.morningstar.com
>>
>> This e-mail contains privileged and confidential information and is
>> intended only for the use of the person(s) named above. Any
>> dissemination, distribution, or duplication of this communication
>> without prior written consent from Morningstar is strictly prohibited.
>> If you have received this message in error, please contact the sender
>> immediately and delete the materials from any computer.
>>
>
>
>
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of DataStax, the source for professional Cassandra support
> http://www.datastax.com
>
Re: Secondary Index keeping track of column names
Posted by Jonathan Ellis <jb...@gmail.com>.
No, 0.7 indexes handle equality queries; you're basically asking for a
IS NOT NULL query.
On Wed, Apr 6, 2011 at 11:23 AM, Jeremiah Jordan
<JE...@morningstar.com> wrote:
> In 0.7.X is there a way to have an automatic secondary index
> which keeps track of what keys contain a certain column? Right now we
> are keeping track of this manually, so we can quickly get all of the
> rows which contain a given column, it would be nice if it was automatic.
>
> -Jeremiah
>
> ________________________________
> Jeremiah Jordan
> Application Developer
> Morningstar, Inc.
>
> Morningstar. Illuminating investing worldwide.
>
> +1 312 696-6128 voice
> jeremiah.jordan@morningstar.com
>
> www.morningstar.com
>
> This e-mail contains privileged and confidential information and is
> intended only for the use of the person(s) named above. Any
> dissemination, distribution, or duplication of this communication
> without prior written consent from Morningstar is strictly prohibited.
> If you have received this message in error, please contact the sender
> immediately and delete the materials from any computer.
>
--
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com