Semantic Drilldown

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Category:MediaWiki extension
Semantic Drilldown
Extension name Semantic Drilldown
About this article / disclaimer
Logo Placeholder.png
Screenshot Placeholder.png
Location of the main author New York
Coordinates of the main authors 40.712728, -74.006015
Developers Yaron Koren, David Loomer
Licences GPL
Description Semantic Drilldown is an extension to Semantic MediaWiki (SMW) that provides a page for drilling down through a site's data, using categories and filters on semantic properties. The list of pages in each top-level category can be viewed, and for each such category, filters can be created that cover a specific semantic property. If filters exist for a category, users can click on the different possible values for those filters, narrowing the set of results, and thus drill down through the data.
Mediawiki requirements Any recent version
Dependencies Semantic MediaWiki
Related extensions (documented here) Semantic Forms
Related extensions
Language support Many
Status stable
First release date 2007/12/01
Last release date (as of 2013/06/26!) 2013/06/01
Last version number 1.2.5 (June 2013)
Programming language PHP
Website home page
Support websites web site
Example websites
Last edited 2013/06/26



Semantic Drilldown is heavily tied in with the Semantic MediaWiki extension, and is meant to be used for drilling down structured data that has semantic markup. You must have version 1.5 or later of Semantic MediaWiki installed for the Semantic Drilldown extension to work: the code will not work without it, or with an earlier version.

Basic use

According, to the Semantic Drilldown page at, you first need "semantic contents", for example Semantic Forms.

(1) Analyze your data

You could use special:browseData to do so.

(2) Create filters

Every filter you want to be able to drill down with has to be defined separately, on a page in the "Filter:" namespace. The easiest way to create a filter is to simply go to the not-yet-created filter page, and click on the "Create with form" tab; this will show the 'CreateFilter' display Or, for you can go directly to Special:CreateFilter.


(3) Add filters to categories

Once you created filters, you can add the tag [[Has filter::Filter:filter-name]] (several possible) to a "semantic" top-level category page.

(4) Include/exclude categories

The use of Semantic DrillDown in a wiki like this one (i.e. not designed from the ground up as semantic mediawiki) requires some adjustments. The DrillDown special pages works from top-level categories. In this wiki there is only one, i.e. "Contents". The others that show up are mistakes :).

We could have used the following strategy to exclude all non-semantic categories:

  • By default no category will show up. In the LocalSettings.php file we set:
$sdgHideCategoriesByDefault = true;

But since we only have a single "normal" top-level category we just inserted this in the Contents page

  • Each category that should show up in the drilldown includes the following string:

Notice: For some weird reasons I can't insert two underscores in a row in the above (i.e. the nowiki filter doesn't work). Therefore use "__" instead of "_" !!

(5) Set some display options

You could set the title of the drilldown page for any specific category, for example:

 This category has the drilldown title [[Has drilldown title::Browse all cities]]. 

More options are available (to document)

Listing all filters