Re: Comment on "Model for Tabular Data and Metadata on the Web": Definition of null field

Thanks David,

It’s a good question. When I wrote it I meant the same as ‘empty field’. I’ve just committed a clarification about it, coupled with an issue in the document to remind me to raise it for discussion on the next call. See:

https://github.com/w3c/csvw/commit/d64c4097671b743da5b98f7b0ca4fcbea1973c27

I don’t think there should be any distinction between an ‘empty field’ and a ‘null field’ at the level of the core data model because I don’t think that common tools (eg Excel) will make the distinction. However, when annotations are added to the mix you might be able to say that an individual field is a null value. (These might not be empty values; some of the use cases we’ve seen are CSVs that use ‘-‘ or ‘999’ to indicate a null value.)

Jeni

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From: David Booth david@dbooth.org
Reply: David Booth david@dbooth.org
Date: 6 April 2014 at 14:58:18
To: public-csv-wg@w3.org public-csv-wg@w3.org, Jeni Tennison jeni@jenitennison.com, 'Gregg Kellogg' gregg@greggkellogg.com
Subject:  Comment on "Model for Tabular Data and Metadata on the Web": Definition of null field

> Hi Jeni and Gregg,
>  
> First of all, very nice work on this!
> http://w3c.github.io/csvw/syntax/
> I haven't read it in detail, but I do have a few comments/suggestions,
> which I will break into separate messages.
>  
> Section 2.1 Core Data Model
> http://w3c.github.io/csvw/syntax/#h3_core-model
> says "Some of these fields may be null fields". What exactly *is* a
> null field? I think this needs to be defined. Is it possible, in the
> absence of assistive metadata, for a CSV+ document to have a null field?
> In a CSV document, how would a null field be distinguishable from a
> field consisting of an empty string? Or are they the same? They
> certainly are not the same in a database.
>  
> Thanks!
> David
>  
>  
>  
>  
>  

--  
Jeni Tennison
http://www.jenitennison.com/

Received on Sunday, 6 April 2014 23:46:03 UTC