ER diagrams

erDiagram draws entities and the cardinality between them. The mark is a crow's foot, not an arrow. || is exactly one, |o is zero or one, }| is one or more, }o is zero or more. The right-hand mark is the mirror (o|, |{, o{). .. draws the same feet on a dashed line.

MermoidAscent.svgDiagram(Mermaid("""erDiagram
    CUSTOMER ||--o{ ORDER : places
    ORDER ||--|{ LINE-ITEM : contains
""".stripMargin))

Attributes

An entity block lists attributes as type name, with PK and FK when the attribute is a key. A quoted string after the name is a comment and stays on the attribute. classDef and style paint the entity the same way they paint a flowchart node.

MermoidAscent.svgDiagram(Mermaid("""erDiagram
    CUSTOMER ||--o{ ORDER : places
    CUSTOMER {
        string name PK
        string sector
    }
    ORDER {
        int orderNumber PK
        string deliveryAddress FK
    }
""".stripMargin))

ER diagrams

#Attributes

Attributes