Core concepts: models, views, sync, and actions

Vocabulary

ViewModel

A named composite model (aggregate/join) over source tables, defined in a *.model.ts file.

Watched columns

The subset of source columns whose changes trigger a re-project. Unwatched columns produce no work.

Projector

A SQL function that takes a set of keys and returns the current composite row(s).

Key map

SQL that maps a changed source row to the ViewModel key(s) it affects.

Delta

A captured insert/update/delete on a source table.

Outbox

A transactional table storing every materialized change for subscriber consumption.

Three guarantees

1. Conditional — a view is enqueued only when an intersected watched column actually changes (IS DISTINCT FROM).
2. Incremental — only affected keys are recomputed, not the whole view.
3. Consistent — after the queue drains, mv_<view> equals a full re-projection from scratch.

Refresh strategies