rdf – addshore

Wikibase Phrase Entity, Viewing

April 11, 2025July 12, 2024 by addshore

This entry is part 7 of 7 in the series Wikibase Entities

In my previous post, we got to the point of being able to create a new Wikibase Entity, it is stored in the MediaWiki database as a page, however we can’t actually view it via any interface currently.

In this post, we will work through another set of code changes, tackling each issue as we see it arise, until we can see the entity represented in the various places that users might expect.

Viewing the page

The provided entity serialization is neither legacy nor current

When clicking on one of the links on Special:RecentChanges to a phrase page that we have created, we get our first error.

/wiki/Phrase:Phrase66900b01937842.29097733 MWContentSerializationException: The provided entity serialization is neither legacy nor current
from /var/www/html/w/extensions/Wikibase/lib/includes/Store/EntityContentDataCodec.php(253)Code language: JavaScript (javascript)

The full stack trace is a little large, but you can find it in a paste bin.

This error is very similar to an issue we saw in the creation blog post, but this time the codec class can not deserialize what we have stored in the database, as we have not registered a deserializer for phrases.

Adding a deserializer to the entity registration file is very simple:

Wikibase, from Entity to EntityDocument

April 11, 2025June 3, 2024 by addshore

This entry is part 2 of 7 in the series Wikibase Entities

The term document has already come up a few times while discussing what a Wikibase entity is, and if that should change (be that in name only, code or structures), including in my first post of this series.

Looking at the very first definition of entity in the duck duck go search that I performed 6 seconds ago, an entity is:

Something that exists as a particular and discrete unit.
The American Heritage® Dictionary of the English Language, 5th Edition

At the most basic level, it’s fairly straightforward to say that a Wikibase doesn’t hold the actual entities (such as a type of tree), rather data about said entities.

And in a nutshell, this data is collected within a document.

Image from “What is the semantic web” by onotext.com

Quoting a few choice people again, before diving deeper into this topic…

The “entities” in the Wikibase base are not Entities. They are descriptions of entities. The entity is the thing in the world not the data we have about it, even tough colloquially, we don’t make the distinction. But we have separate URIs for the thing and the description in the abstract and for specific renderings.
I think that’s important to mention when discussing what an entity “is”.
Daniel Kinzler in conversation, June 2024

The data model chose to use the term “Entity” for the top-level Thing/class in the hierarchy of the data model. But in reality, a better term would have been “Document” or “Record”. In general, the confusion is often due simply to folks that are more familiar with one of the domains than the other, between OOP Objects and Semantic Web Objects.
Thad Guidry in a comment, June 2024

Changing the concept URI of an existing Wikibase with data

November 6, 2019November 5, 2019 by addshore

Many users of Wikibase find themselves in a position where they need to change the concept URI of an existing Wikibase for one or more reasons, such as a domain name update or desire to have https concept URIs instead of HTTP.

Below I walk through a minimal example of how this can be done using a small amount of data and the Wikibase Docker images. If you are not using the Docker images the steps should still work, but you do not need to worry about copying files into and out of containers or running commands inside containers.