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From aaron morton <aa...@thelastpickle.com>
Subject Re: how to know there are some columns in a row
Date Wed, 08 Jun 2011 00:18:25 GMT
> If you have a method to retrieve the number of columns of a row (without their values),
 I can't see why you couldn't retrieve the column names (without their values). It's perharps
harder than I think... But it would be rather useful ! 

Internally this just gets the full columns and counts them. 

The main reason I was dismissive was the complication it brings when dealing with a Column.
If a Column has no value would it be because there is no value associated with it or because
only the column name was requested? For now when you have a Column you have all the information
about the column. 

There may also be some modelling arguments to be made. 

it's not been a show stopper for people in the past, but that does not mean it's a bad idea.

Cheers

-----------------
Aaron Morton
Freelance Cassandra Developer
@aaronmorton
http://www.thelastpickle.com

On 8 Jun 2011, at 10:30, Patrick de Torcy wrote:

> But I want values in my columns... Imagine a cf with authors as keys. Each author has
written several books. So each row has columns with the title as column names and the text
of the book as value (ie a lot of data). If a user wants to know the different books for an
author, I'd like to be able to have the column names without the values, then a user can pick
a book name. In this case I can retrieve the value from this column (and only for this one).
> Of course, I could have an additionnal column which will manage the column names (=titles),
but it's not very efficient and could be source of errors...
> If you have a method to retrieve the number of columns of a row (without their values),
 I can't see why you couldn't retrieve the column names (without their values). It's perharps
harder than I think... But it would be rather useful ! 
> 
> Thanks !
> 
> On Mon, Jun 6, 2011 at 2:08 AM, aaron morton <aaron@thelastpickle.com> wrote:
> You can create columns without values. 
> 
> Are you talking about reading them back through the API ? 
> 
> I would suggest looking at your data model to see if there is a better way to support
your read patterns. 
> 
> Cheers
> 
> -----------------
> Aaron Morton 
> Freelance Cassandra Developer
> @aaronmorton
> http://www.thelastpickle.com
> 
> On 6 Jun 2011, at 10:18, Patrick de Torcy wrote:
> 
>> It would be definetely useful to be able to have columns (or super columns) names
WITHOUT their values. If these ones are pretty big or if there are a lot of columns, that
would generate traffic not necessarily needed (if in the end you are just interrested by some
column).
>> Moreover it doesn't seem to be a feature too difficult to implement (well, I think...)
>> 
>> Patrick
> 
> 


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