Re: [Semediawiki-user] How to retrieve data with empty (null) properies

[Yaron K. <ya...@gm...>]

I don't believe this is directly possible in SMW. I can think of two
workarounds, though:

- You can create a new Boolean semantic property, perhaps called "Has effort
value", that is set using an #if call; and then query on that property. This
is easier if you're using templates to store the data, but if not, you can
use a call to #show to get the value.

- The Semantic Drilldown extension can display the pages that have no value
for a property.

-Yaron


On Wed, Feb 25, 2009 at 10:59 AM, planetenxin <pla...@we...> wrote:

>
> Hi forum,
>
> i have properties that are not mandatory and therefore sometimes populated
> and sometimes not. I'd like to retrieve all pages with an "empty" property
> e.g. all pages where the optional property "Effort" is not set:
>
> {{#ask: [[Category:Requirement]][[Effort::NULL]]
> | ? Realized By Project
> | ? Binding Character
> | ? Process Word
> | ? Effort = Effort (MD)
> }}
>
> There are also other examples where the datatype is a string or text, e.g.
> "Realized By Project"
>
> /planetenxin
> --
> View this message in context:
> http://www.nabble.com/How-to-retrieve-data-with-empty-%28null%29-properies-tp22205767p22205767.html
> Sent from the Semantic Mediawiki - User mailing list archive at Nabble.com.
>
>
>
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