[Developers] Question about references to wikipedia articles

[Colin Evans]

Hi Kavitha,
Every Freebase topic that has a corresponding Wikipedia topic has a set 
of keys with the namespace "/wikipedia/en" and also a "/wikipedia/en_id" 
key.  You can see examples of those keys here: 
http://freebase.com/view/explore/topic/en/abraham_lincoln

The "en" keys are the Wikipedia article titles and redirects that 
correspond to the Freebase topic.  The "en_id" is the Wikipedia page_id 
from the Mediawiki database.

We re-synchronize with Wikipedia roughly twice a month, with a strong 
emphasis on keeping Freebase topics stable.  Thus, if a page is split, 
merged, moved, or deleted in Wikipedia, the corresponding topic(s) in 
Freebase will reflect the changes conservatively or maybe not at all, 
depending on the data and our current sync algorithm.  We work hard to 
keep Freebase.com aligned with Wikipedia, so for most cases the "en" 
keys should be a good mapping.

The dbpedia extraction is run on a regular basis from scratch, and 
therefore their canonical reference is to a specific article version in 
a specific Wikipedia dump.  Because Freebase.com is continuously 
synchronizing with Wikipedia, there isn't a more canonical reference 
than the "en" and "en_id" keys. 

If you're looking to reconcile a specific dbpedia dump with 
Freebase.com, I'd recommend aligning on article names and redirects -- 
the "en" keys in Freebase.  There may be some inconsistencies as 
Wikiepdia redirects move around over time, but this will probably work 
for the majority of records. 

Also, I'd like to get in a plug for the new Freebase Wikipedia 
Extraction, which is the basis for a lot of our sync algorithms and data 
mining of Wikipdia.  The "freebase_names" table has a mapping of 
Freebase guids to Wikipedia article names, which should make alignment 
easier: http://download.freebase.com/wex/doc/#freebase_names

Hope that helps!
-Colin

Kavitha Srinivas wrote:
> Is there a way to get a canonical reference to the current version of  
> the wikipedia article for a given guid in freebase?  We are trying to  
> establish connections between freebase and dbpedia, and it looks like  
> dbpedia has a canonical reference, whereas freebase uses a link to  
> the version from which it was created.  Finding equivalences between  
> dbpedia and freebase has not been easy, and is prone to errors.  Thanks!
> Kavitha
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