Extension:SemanticUpdateOnPurge

The SemanticUpdateOnPurge extension updates all semantic data created with Semantic MediaWiki when purging a page. This extension is motivated by bug 22751 which actually isn't considered a real bug. Anyway, with this extension "dynamic attributes" are more comfortable and efficient to use if you have to use them. However, as you can see in the bug report, it is not recommended or supported by the SMW developers to use inline query results in attributes.

Another scenario where this extension can be useful is if you use the External Data extension. If your external data sources change their values you can simply update the semantics on the MW article by pressing purge.

Compatibility
The extension works with Semantic-MediaWiki 1.6.x (and probably 1.6). It does not work with MediaWiki 1.18 currently. There were reports that the functionality was broken somewhere around the 1.5.x branch of SMW, though, it has been reported working with some older SMW versions than 1.6 as well (current version should at least work with some old SMW versions).