Schemas

Date: April 2023

Status: Accepted, format specification superseded by ADR 009

Context

Users should be able to define properties and also specify which properties are expected for a given type of Subject.

Semantic MediaWiki and Wikibase both work with "global properties" and lack first-class schema support. In Semantic MediaWiki schema support is somewhat emulated via templates and Page Forms, though the core software does not understand or enforce those schemas.

Decision

• We have Schemas that define the type of a Subject and the properties that are expected for that type.
• Schemas are defined in JSON
• Schemas are stored on dedicated pages in the Schema namespace
• Schemas follow the JSON Schema specification

Consequences

• We can build forms to create and edit subjects based on their schema.
• We can validate subjects against their schema.
• We can build UIs for creating and editing schemas.
• Properties are namespaced within their schema instead of global. Thus, different types/schemas can have properties with the same name but a different definition.