Extension:Semantic Drilldown


 * The following is the introductory section of http://www.mediawiki.org/wiki/Extension:Semantic_Drilldown on the Mediawiki website. Check that page for more detail and possible updating.

Semantic Drilldown is an extension to MediaWiki that provides a page for drilling down through a site's data, using categories and filters on semantic properties. It is heavily tied in with the Semantic MediaWiki extension, and is meant to be used for 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.

The "Browse data" page is the heart of the extension. It lists all the 'top-level' categories in the wiki; i.e., the categories that are not subcategories of another category, and the number of pages within that category. Each category name is a link to a 'drilldown' for the pages in that category. It lets the user select additional constraints to limit the number of results. These constraints come in two types:


 * Subcategories - if the category has any subcategories, those will show up in a "Subcategory" row. Each one will be a link that will let the user view only the pages that belong to that subcategory. The resulting drilldown page will include links for all the filters for the top-level category, and any subcategories of the selected subcategory. You can thus use the "Browse data" page to navigate through the entire category tree.


 * Filters - filters based on semantic properties can be manually created and added to any top-level category. Each such filter gets its own row within the constraints area, to let the user limit the results to only those pages that have certain values for a semantic property. There are four ways to set the possible values for a filter (described in detail below):
 * From property values - the default method; the filter simply shows all current values for this property.
 * Pages in a category - the filter's values can be all the pages that belong, either directly or through a subcategory, to a category.
 * By date range - results are grouped into date ranges, based on a specified time period.
 * Set manually - the filter's values can be set manually. For properties that are numbers, a numerical range can also be set for a filter value, instead of a single number.



In the display of the filter in the drilldown, values that do not have any results for them will not be displayed. The filter will also show two additional values: "Other" and "None". Pages that show up for "Other" are those that have a value for that filter's property other than one of the pre-specified values. Pages that show up for "None" are those that have no value for that property. "Other" and "None", like other filter values, will not show up if there are no results for them.

After any amount of clicking on different subcategories and filters, the user will be able to see, in the page header near the top of the page, the set of subcategories and filters he/she has clicked on, that currently set constraints on the result. The user can get rid of any constraint by clicking on the "x" next to its name in the header.

The drilldown 'results', i.e. the set of pages displayed at any given time during the drilling-down, are by default displayed in the same manner as in MediaWiki's category page; this display, however, can be customized, to show additional values for each page, or to show results in other formats such as tables, maps and timelines.