Domain Model

The asset model tracks identity, custody, tags, lifecycle events, documents, compliance, and maintenance.

Core Entities

Entity	Purpose
`app_user`	Person using the system
`role` / `permission`	Authorization model
`department`	Owning organizational unit
`location`	Physical asset location
`party`	User, department, or vendor in a handoff
`asset`	Current asset read model derived from events
`asset_tag`	Tag history for an asset
`asset_event`	Append-only action log
`handoff_transaction`	Two-sided custody transfer
`handoff_line`	Assets included in a handoff
`discrepancy`	Mismatch between record and reality
`approval`	Maker-checker decision
`financial_profile`	Asset financial view
`compliance_item`	Warranty, certificate, maintenance due date, lease end
`document`	Asset file attachment
`work_order`	Maintenance job

Entity Relationships

erDiagram
    app_user ||--o{ user_role : has
    role ||--o{ user_role : assigned
    role ||--o{ role_permission : grants
    permission ||--o{ role_permission : included
    department ||--o{ asset : owns
    location ||--o{ asset : contains
    app_user ||--o{ asset : custodian
    asset ||--o{ asset_tag : tagged_by
    asset ||--o{ asset_event : has
    party ||--o{ handoff_transaction : from
    party ||--o{ handoff_transaction : to
    handoff_transaction ||--o{ handoff_line : contains
    asset ||--o{ handoff_line : moved
    asset ||--o{ discrepancy : reports
    asset ||--o{ financial_profile : has
    asset ||--o{ compliance_item : tracks
    asset ||--o{ document : attaches
    asset ||--o{ work_order : maintains

Invariants

Asset history is append-only.
Current asset state is derived from events.
A correction points to an earlier event; it does not overwrite it.
A handoff closes only when the receiver confirms.
Maker and checker must differ for approvals.
Tags are globally unique while active.
Missing or temporary tags create follow-up work, not blocked receiving.

Mobile POC Domain Mapping

The current POC uses simplified Dart models in reference/mobile_app_demo/lib/models/:

Dart model	Concept
`Grn`	Delivery work list
`GrnLineItem`	Physical unit expected or received
`AssetEvent`	Local event queued for backend sync
`OnboardedAsset`	In-memory current view

See Data Model Reference for table-level fields.