# Entity relationship (core)

```mermaid
erDiagram
    tenants ||--o{ users : has
    tenants ||--o{ products : owns
    tenants ||--o{ orders : owns
    tenants ||--o{ customers : owns
    tenants ||--|| tenant_subscriptions : has
    orders ||--o{ order_items : contains
    order_items }o--|| products : references
    marketplace_carts ||--o{ marketplace_cart_items : contains
    marketplace_orders ||--o{ marketplace_order_lines : splits
    system_backups {
        bigint id PK
        string filename
        string status
    }
    slo_request_samples {
        bigint id PK
        string route
        int duration_ms
    }
```