Domain Model

Signal defines no schema of its own. Its only persisted entity is ActivityNotification, whose table, model, and repository all live in @nx/core. Connection and AES-key state are held in-memory per instance and are not modeled here.

1. Full ERD

ActivityNotification has no foreign-key relations in the schema — recipientId and organizerId are soft references to user / organizer IDs resolved at write time.

2. Entities

ActivityNotification

Property	Value
Table	ActivityNotification
Source	packages/core/src/models/schemas/public/activity-notification/schema.ts
Model	packages/core/src/models/schemas/public/activity-notification/model.ts
Repository	ActivityNotificationRepository (@nx/core)
Soft-delete	yes (SoftDeletableRepository, deletedAt)
Owner ID column	recipientId (per-user)

Fields:

Field	Type	Required	Default	Description
id	text	✓	Snowflake	Primary key
recipientId	text	✓	—	Target user; one row per recipient
type	varchar(80)	✓	—	TActivityNotificationTypes (see enum)
organizerId	text		null	Owning organizer, if scoped
content	text	✓	—	Rendered plain-text content
html	text	✓	—	Rendered HTML content
actionUrl	text		null	Deep-link target
data	jsonb	✓	{}	Actor + event payload snapshot
isRead	boolean	✓	false	Read flag
readAt	timestamptz		null	Set when marked read

Type enum (ActivityNotificationTypes):

Value	Description
PAYMENT_SUCCESS	Only type implemented today; rendered from the actor + payment payload

The worker rejects any eventType not in ActivityNotificationTypes.SCHEME_SET (logs a warning and skips).

Indexes:

Name	Columns	Purpose
IDX_ActivityNotification_recipientId_isDeleted_createdAt	recipient_id, deleted_at, created_at	Bell query — recipient's notifications, newest first
IDX_ActivityNotification_recipientId_isRead	recipient_id, is_read	Unread count
IDX_ActivityNotification_organizerId_type_createdAt	organizer_id, type, created_at	Filter by organizer + type

Relations: none declared in schema (recipientId / organizerId are soft references).

3. Cross-entity Invariants

Invariant	Enforcement
One row per recipient per fan-out	Worker loops over resolved recipients and createAlls a row each
readAt set ⇔ isRead = true	ActivityNotificationService.markAsRead / markAllAsRead set both together
Recipient can only read/mutate their own rows	Controller scopes every query by recipientId = JWT subject

4. Soft-delete Behavior

Behavior	Detail
Read default	deletedAt IS NULL (model defaultFilter)
Hard-delete	not used by signal
Restore	not exposed

5. Related Pages

• Architecture
• API Events
• Decisions