2. Vertical Slices

The spine of this wiki.

A slice documents one realistic UI action end-to-end: from the click in the browser to the row written in the database, passing through every layer in between — the metadata read, the proc invoked, the cache invalidated. Slices are the only place we write narrative prose. Concepts and reference chapters are short by design; slices carry the load.

Slices are ordered by complexity. Each new slice introduces a new framework concept. Re-read earlier slices once you've read later ones — the cross-refs back-fill.

#	Slice	Concept(s) introduced
1	a CRUD module (Hello World)	modules, forms, master/slave, jurisdiction
2	multi-tenancy and product editions	sBrandsId/sSubsidiaryId scoping, licence-gated editions
3	a module with a report	views, report templates, jxls
4	extending — a custom field	gdsconfigformcustomslave, schema-less extension
5	extending — a per-customer SQL override	script/客户/, override channel
6	a hardware-integrated module	xlyPlc, serial, RPC into the press
7	a module with workflow (deferred)	Activiti, biz_flow, approval — needs a deployment with active flows

Slices 1–5 are mainstream. Slice 6 is optional for readers who'll never touch hardware. Slice 7 is deferred: it needs a deployment that actually runs an approval flow before it can be traced end-to-end.