Semantic MediaWiki combining templates and properties - Tutorial 12

Semantic MediaWiki’s real leverage comes from letting templates assign semantic properties automatically—turning page content into structured, queryable data without manual bookkeeping. Instead of only transcluding a template for display, the workflow here injects a property value through template parameters, so the same template can stamp different pages with different property values.

The tutorial builds on earlier template-variable mechanics: templates accept parameters via double curly braces, and the parameter values flow into the template’s internal logic. The key upgrade is inserting a semantic property “inside” the template. A property name is placed where the template variable would be, and the template parameter becomes the property value. In the example, the template is designed to set a property called “has page warning property,” whose allowed values are constrained to three options: inaccurate, incomplete, or draft. That value constraint matters because it keeps the wiki’s data consistent and makes later searches reliable.

To make this work smoothly, the template also needs a default property value. When no parameter is provided, the template should still emit a valid property assignment. The tutorial demonstrates setting the default to inaccurate, so pages using the template without an explicit parameter automatically become “inaccurate.” It then shows how the template output is converted into a semantic property assignment by using Semantic MediaWiki syntax: the template emits something equivalent to “has page warning property:: <value>”.

Once the property is created and its allowed values are limited (via Special:Create property), the tutorial demonstrates the practical payoff. Several pages are edited to use the template with different parameter values—one set to inaccurate, another to draft, and another to draft and then changed to inaccurate. After each change, the pages’ “Browse properties” section updates accordingly, confirming that template parameters are driving the semantic property values.

The final step shows why this matters: queries become effortless. A separate page (“inaccurate”) is used to collect all pages whose “has page warning property” equals inaccurate. When a page’s template parameter changes from draft to inaccurate, the query results update after a refresh, and the page list grows to include the newly updated page. The workflow scales beyond a single property: with more properties and more templates, a wiki can maintain structured status fields (accuracy, completeness, review state, recency, view counts) and generate dynamic lists of pages that match those criteria.

The takeaway is straightforward: combine templates, parameterized variables, property constraints, and defaults so semantic properties stay synchronized with page content. That sets up the next phase—building larger templates and using forms (often via infobox-style UI patterns) to fill these templates quickly and consistently across many pages.