# [Financial Crime](../domain.md)

## Entities

### Customer

A Customer is a Party Role representing an active or prospective relationship with the institution for products and services.

```mermaid
---
config:
  layout: elk
---
classDiagram
  class Customer{
    * Customer Number : string
    Onboarding Date : date
    Relationship Start Date : date
  }

  Customer --|> PartyRole
  Customer "0..*" --> "0..*" Account : holds
  Customer "1" --> "0..1" CustomerPreferences : has

  class PartyRole["<a href='https://github.com/Semprini/md-ddl/blob/main/examples/Financial%20Crime/entities/party_role.md'>Party Role</a>"]
  class Account["<a href='https://github.com/Semprini/md-ddl/blob/main/examples/Financial%20Crime/entities/account.md'>Account</a>"]
  class CustomerPreferences["<a href='https://github.com/Semprini/md-ddl/blob/main/examples/Financial%20Crime/entities/customer-preferences.md'>Customer Preferences</a>"]
```

```yaml
extends: Party Role
existence: independent
mutability: slowly_changing
attributes:
  Customer Number:
    type: string
    identifier: primary
    description: Unique customer identifier used for service and support operations.

  Onboarding Date:
    type: date
    description: Date the customer onboarding process was completed.

  Relationship Start Date:
    type: date
    description: Date the customer relationship became effective.
```

```yaml
governance:
  retention_basis: Inherited from domain default retention of 10 years post relationship end for AML/CTF record-keeping
```

## Relationships

### Customer Holds Account

A Customer can hold one or more Accounts, and an Account can be held by one or more Customers. Joint accounts, business accounts with multiple authorized signatories, and beneficial ownership structures all require many-to-many cardinality. In the Financial Crime domain this is the structural basis for network analysis — connecting Customers through shared Accounts.

```yaml
source: Customer
type: has
target: Account
cardinality: many-to-many
granularity: atomic
ownership: Customer
relationship_attributes:
  - Holder Type (enum:Account Holder Type)
  - Holder Start Date
  - Holder End Date
  - Is Primary Holder
```

### Customer Has Preferences

A Customer has at most one active Customer Preferences profile at a time.

```yaml
source: Customer
type: has
target: Customer Preferences
cardinality: one-to-one
granularity: atomic
ownership: Customer
```