ERD

erDiagram
  drug_record {
    bigint drug_record_id PK
    varchar organisation PK
    bigint patient_id FK
    bigint authorising_user_in_role_id FK
    bigint original_authorising_user_in_role_id FK
    bigint entered_by_user_in_role_id FK
    bigint cancelled_by_user_in_role_id FK
    bigint most_recent_issue_record_id FK
  }

  patient {
    bigint patient_id PK
    varchar organisation PK
  }

  user_in_role {
    bigint user_in_role_id PK
    varchar organisation FK
  }

  issue_record {
    bigint issue_record_id PK
    varchar organisation PK
  }

  drug_record }o--|| patient : "belongs to"
  drug_record }o--o| user_in_role : "authorising_user_in_role_id"
  drug_record }o--o| user_in_role : "original_authorising_user_in_role_id"
  drug_record }o--o| user_in_role : "entered_by_user_in_role_id"
  drug_record }o--o| user_in_role : "cancelled_by_user_in_role_id"
  drug_record }o--o| issue_record : "most_recent_issue_record_id"