Admin: Automated edit (via update-page on MediaWiki MCP Server)

2026-07-06T05:20:21Z

Automated edit (via update-page on MediaWiki MCP Server)

← Older revision		Revision as of 10:50, 6 July 2026
Line 1:		Line 1:
	{{Doc header		{{Doc header
	\|type=guide		\|type=guide
	\|domain=platform
	\|title=Model Forking Demo		\|title=Model Forking Demo
	\|order=999		\|order=999

Admin: Automated edit (via create-page on MediaWiki MCP Server)

2026-07-06T05:16:42Z

Automated edit (via create-page on MediaWiki MCP Server)

New page

{{Doc header
|type=guide
|domain=platform
|title=Model Forking Demo
|order=999
|introduced=1.0
}}

{{Info|title=Sandbox demonstration|1=This page demonstrates a '''model forking (branching)''' workflow using the wiki's copy-on-write versioning and Cargo/SMW stack. While the [[Sandbox/Version demo|version demo]] shows time-based evolution, this demo shows '''parallel forks''' maintained by different entities with an upstream/downstream sync relationship.}}

== The problem ==

When multiple organizations adopt a shared data model:

* They need '''custom fields''' for their specific workflows
* They can't be forced to accept every upstream change immediately
* They need to '''cherry-pick''' which upstream changes to adopt
* The upstream needs to evolve without breaking downstream consumers

This is the same problem '''git branches''' solve in source code — applied to data model governance.

== The forking workflow ==

{| class="wikitable"
! Step !! What happens
|-
| '''1. Publish''' || The development entity publishes the canonical model (single source of truth).
|-
| '''2. Fork''' || A production entity copies the model at a specific version and begins maintaining its own fork.
|-
| '''3. Diverge''' || Both sides evolve independently. The dev entity adds/removes/renames fields rapidly. The prod entity adds its own custom fields.
|-
| '''4. Sync''' || The prod entity chooses to pull in upstream changes — deciding per-field whether to adopt, adapt, or decline.
|-
| '''5. Repeat''' || This is a continuous cycle, not a one-time migration.
|}

== The models ==

=== Upstream (source of truth) ===

* [[Sandbox/ModelFork/DevEntity/PatientModel|DevEntity PatientModel (latest — v2.0.0)]]
* [[Sandbox/ModelFork/DevEntity/PatientModel/1.0.0|DevEntity PatientModel v1.0.0]] (frozen snapshot — copy-on-write fork)

=== Downstream (production forks) ===

* [[Sandbox/ModelFork/Prod/AcmeCare/PatientModel|AcmeCare PatientModel]] — Forked from Dev v1.0.0, added insurance + physician fields

== Key differences from versioning ==

{| class="wikitable"
! Dimension !! Versioning ([[Sandbox/Version demo|demo]]) !! Forking (this demo)
|-
| '''Axis''' || Time (1.0 → 2.0 → 3.0) || Space (Dev ← Prod₁, Dev ← Prod₂)
|-
| '''Ownership''' || Single entity || Multiple independent entities
|-
| '''Divergence''' || Accumulates, rarely removes || Can diverge significantly
|-
| '''Sync''' || Not applicable || Selective cherry-pick from upstream
|-
| '''Copy-on-write''' || Version freeze → subpage || Fork creation → subpage
|}

== Structured field data ==

Every model below stores its fields in the [[Special:CargoTables/ModelField|ModelField]] Cargo table. This query shows all fields across all forks:

{{#cargo_query:tables=ModelField
|fields=Model,Field,FieldType,Notes
|where=Model LIKE 'PatientModel%'
|order by=Model, Field
|format=table
}}

[[Category:Sandbox]]

Sandbox/ModelFork - Revision history

Admin: Automated edit (via update-page on MediaWiki MCP Server)

Admin: Automated edit (via create-page on MediaWiki MCP Server)