ER: Attribute Comments
Attribute comments (#2127). Mermaid shows them as a fourth column after the keys and never wraps them; the ASCII panel appends them to the row in quotes, also unwrapped, and a `<br>` becomes a space. The SVG keeps them as a hover tooltip. An entity without comments is drawn as before.
er-attribute-comments.mmd
erDiagram
CUSTOMER ||--o{ ORDER : places
CUSTOMER {
string name PK "the primary key"
string email UK "login address<br>must be unique"
int age
}
ORDER {
int id PK
int customer_id FK "references CUSTOMER, deleted orders are archived rather than removed"
}