SemanticPropagation

This page has been built to document a problem that sometimes occurs in Semantic Mediawiki (we still do not know if it is typical of every installation, but at least it is for our version of the software).

The use-case for this problem is the following: someone needs to add a new research area. So she creates a new wiki page and copies the main structure from another research area, modifying the template to fit the new information. However, after this modification the update is not propagated to all the other pages that should use this information. Why? How can this problem be fixed?

Well, the "why" part is the more difficult to answer :-) Actually parts of Semantic Mediawiki are still not 100% stable and documented, however we have an idea: the new semantic information is added when the new page is saved, however it needs to be propagated to the others. In particular, templates or pages that embed this knowledge in the form of an ASK query should be refreshed (probably there is also a cache problem?)

So, when you perform an operation similar to the one we just described you should also be aware of the other pages that might use this information. Once you create the new page, go and check the other pages in the same order in which they access this information. For instance, if you create a new research area:

• check the page Research Areas. If the area does not appear, refresh the page. If refresh does not work, open it for editing and save it even without modifying it, then check again;
• check the page Property:PrjResArea, which matches projects with research areas, refresh and check as above;
• check the page Property:HasResArea, which matches people with research areas, refresh and check as above.

If at the end of your operations the research area correctly appears in all the pages, then the "bug" should be fixed.

If you happen to find another use-case for this error, please document it here so everyone who is going to have similar problems in the future will find an answer to her problems here!