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Mermaid Diagrams

Use Mermaid Diagrams to communicate complex relationships and interconnections between different technical components. You describe the diagram following the Mermaid Diagram Syntax. The generator subsequently produces the diagram for you. Mermaid Diagrams support a great variety of diagrams for which a few examples are included.

Flowcharts

Flowcharts represent workflows or processes. The steps are rendered as nodes of various kinds and are connected by edges.

Flow chart
```mermaid
graph LR
  A[Start] --> B{Error?};
  B -->|Yes| C[Hmm...];
  C --> D[Debug];
  D --> B;
  B ---->|No| E[Yay!];
```

Result:

graph LR
  A[Start] --> B{Error?};
  B -->|Yes| C[Hmm...];
  C --> D[Debug];
  D --> B;
  B ---->|No| E[Yay!];

Sequence Diagrams

Sequence diagrams describe a specific scenario as sequential interactions between multiple objects or actors, including the messages that are exchanged between those actors.

Sequence diagram
```mermaid
sequenceDiagram
  Alice->>John: Hello John, how are you?
  loop Healthcheck
      John->>John: Fight against hypochondria
  end
  Note right of John: Rational thoughts!
  John-->>Alice: Great!
  John->>Bob: How about you?
  Bob-->>John: Jolly good!
```

Result:

sequenceDiagram
  Alice->>John: Hello John, how are you?
  loop Healthcheck
      John->>John: Fight against hypochondria
  end
  Note right of John: Rational thoughts!
  John-->>Alice: Great!
  John->>Bob: How about you?
  Bob-->>John: Jolly good!

State Diagrams

State diagrams describe the behavior of a system, decomposing it into a finite number of states, and transitions between those states.

State diagram
```mermaid
stateDiagram-v2
  state fork_state <<fork>>
    [*] --> fork_state
    fork_state --> State2
    fork_state --> State3

    state join_state <<join>>
    State2 --> join_state
    State3 --> join_state
    join_state --> State4
    State4 --> [*]
```

Result:

stateDiagram-v2
  state fork_state <<fork>>
    [*] --> fork_state
    fork_state --> State2
    fork_state --> State3

    state join_state <<join>>
    State2 --> join_state
    State3 --> join_state
    join_state --> State4
    State4 --> [*]

Class Diagrams

Class diagrams describe the structure of a system by modelling entities as classes and relationships between them.

Class diagram
```mermaid
classDiagram
  Person <|-- Student
  Person <|-- Professor
  Person : +String name
  Person : +String phoneNumber
  Person : +String emailAddress
  Person: +purchaseParkingPass()
  Address "1" <-- "0..1" Person:lives at
  class Student{
    +int studentNumber
    +int averageMark
    +isEligibleToEnrol()
    +getSeminarsTaken()
  }
  class Professor{
    +int salary
  }
  class Address{
    +String street
    +String city
    +String state
    +int postalCode
    +String country
    -validate()
    +outputAsLabel()
  }
```

Result:

classDiagram
  Person <|-- Student
  Person <|-- Professor
  Person : +String name
  Person : +String phoneNumber
  Person : +String emailAddress
  Person: +purchaseParkingPass()
  Address "1" <-- "0..1" Person:lives at
  class Student{
    +int studentNumber
    +int averageMark
    +isEligibleToEnrol()
    +getSeminarsTaken()
  }
  class Professor{
    +int salary
  }
  class Address{
    +String street
    +String city
    +String state
    +int postalCode
    +String country
    -validate()
    +outputAsLabel()
  }

Entity-Relationship Diagrams

An entity-relationship diagram specifies relationships that between entities and the properties of entities.

Entity-relationship diagram
```mermaid
erDiagram
  CUSTOMER ||--o{ ORDER : places
  ORDER ||--|{ LINE-ITEM : contains
  CUSTOMER }|..|{ DELIVERY-ADDRESS : uses
```

Result:

erDiagram
  CUSTOMER ||--o{ ORDER : places
  ORDER ||--|{ LINE-ITEM : contains
  CUSTOMER }|..|{ DELIVERY-ADDRESS : uses