Entities, stores and migrations

An entity is a kind of stored record with a lasting identity, like a table with types.

A field's settings, such as generated:, unique: and on_delete:, go in a block after its type, one per line.

unique: true in a field's block means no two records may hold the same value in that field.

Any field typed X.id is a reference to a record of X.

A parent doesn't declare its children.

A lifecycle describes the stages a record goes through and when it drops out of normal view.

A store is somewhere your app keeps records: a PostgreSQL database, or a Redis server.

A field whose type is one of your app's enums with data, objects, lists, sets or maps is kept in one jsonb column.

You never name a column type.

You don't write the indexes your queries need.

Entities describe the schema you want.

A backfill can be an expression over each row's own stored fields, so a migration can reshape data rather than only fill it with one value.

A seed creates data for development by calling your app's own actions, so validation, lifecycle and policy apply to it.

An entity may live in a Redis store, for data that is short-lived and harmless to lose.

An entity's file holds only its data definition: its store, fields, unique rules, indexes, lifecycle, policy and record cache.

The runtime needs tables of its own, for example to hold events until they are delivered.