I think that DBpedia links to Wikipedia by Wikipedia database dump, making it not up to date with on-line Wikipedia contents.
I was wondering if Wikidata uses on-line Wikipedia content or if it also works on Wikipedia dump?
The dependency is supposed to be the opposite, i.e. that Wikipedia should rely on data in Wikidata. This is however not fully implemented yet. If you look at the infobox on this cheese in French, all data comes from Wikidata, but not in English (yet). We are far from full implementation, so expect to see any combination of people pulling data from Wikipedia to Wikidata or the opposite in any article.
Wikidata doesn't automatically use data from Wikipedia. Data from Wikipedia is uploaded to Wikidata by hand or using some more or less automated tools to do batch uploads but ultimately under control of a user, as PetScan or Wikidata Game. The uploading work is in progress with thousands of articles in Wikipedias without an item in Wikidata and millions of items in Wikidata which lack some of the data that is in Wikipedias. For example, there is over a million of Wikidata items labelled as "human" but lacking gender, while most of those items have gender in some Wikipedia article explained in some human-readable way.
Use of Wikidata data in Wikipedias is only half automated: usually infoboxes and other templates in articles can use data from Wikidata but that need to be enabled in the infobox (and usually it's not straightforward) and it can be overridden by data locally stored in Wikipedia article. The effort of allowing that data to be used has often been done for data that is expected to be more updated in Wikidata (for example, geographical coordinates) but it isn't likely to be completed in a foreseeable future for data that is already right in Wikipedias and is not likely to get outdated.
And as Ainali expects, there is actually a lot of people pulling data from Wikipedias to Wikidata (my example) or updating templates in Wikipedia to use data from Wikidata.