Wikidata is a new addition to the WikiMedia foundation that focusses on providing machine-readable data that can be re-used by other sites.

SemanticMediaWiki is a large extension for mediawiki that allows users to embed semantic data in the wiki.

SemanticMediawiki has been around for ages, and seems to have a solid userbase. I'm interested in setting up an open data site, and am considering these two options. I'm wondering why WikiData decided to build their own solution, rather than use SemanticMediawiki? And what are the pros and cons of each solution?

  • Could you please provide more details about what kind of "open data site" you have in mind? Feb 5, 2015 at 10:16
  • I don't know enough about the two projects, but some of the 'semantic web' type solutions aren't always as efficient as flat tabular data. They're better for linking sparsely populated information. W3C has a list of 'Large Triple Stores' and when you consider that each triple is a single fact ... I have DB tables w/ 185 fields and 150M rows. That would put me at #4 on the list ... and that's only one table in that database.
    – Joe
    Feb 5, 2015 at 13:16
  • A single table with 185 fields? O_o That seems like a fairly unusual situation. @PatrickHoefler: I'd prefer not to discuss specifics, but something like a database of places, people, and organisations, that includes the ability to easily enter data and perform complex queries (like "give me a map of all the places owned by organisations related to this person" or similar).
    – naught101
    Feb 6, 2015 at 0:26

1 Answer 1


It really depends on what you're trying to achieve.

This is what the Semantic Mediawiki project has to say on the relationship between Semantic MediaWiki and Wikidata:

The software that powers Wikidata is a set of MediaWiki extensions collectively known as Wikibase, and though Wikibase has similarities to Semantic MediaWiki, it is a distinct set of software. However, some of SMW's backend code has been spun off into a separate library, called "DataValues", that is used by both SMW and Wikibase as a framework for storing data.

There is the potential that Wikibase and Semantic MediaWiki will compete against one another as software, with some wikis choosing to use Wikibase instead of SMW as their data storage system. This seems doubtful, however: the Wikibase user interface is geared for a highly multilingual, highly general knowledge base like Wikipedia. Wikis with a specific focus and only one or a handful of languages would be better off with the greater structure and simplicity of Semantic MediaWiki.

They also have a dedicated page explaining some of the differences between SMW and Wikidata:

The main use case of Wikidata (a centralised, multi-lingual site that serves as a data repository) is different from that of SMW (a data-enhanced MediaWiki), and this leads to a number of differences.

Central to a wikidata statement is that its factual claim is supported by reference(s) (source of the claim). For example, when SMW makes a claim about the population of Berlin it would only be annotated with Berlin has a population of 3,5 Mio where Wikidata would make an extended statement describing it as Berlin's population being 3,5 Mio as of 2011 according to the German statistical office.

  • Ah, great info. I guess that extra info that wikidata stores necessarily makes its UI more complicated, it's a trade-off...
    – naught101
    Feb 5, 2015 at 13:14

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