HomeDiagramsER diagramER: Basic Relationship

ER: Basic Relationship

A simple one-to-many relationship between two entities.

er-basic-relationship.mmd
erDiagram
  CUSTOMER ||--o{ ORDER : places
Output
ER diagram, Zombie Mermaid CUSTOMER (no attributes) ORDER (no attributes) places

More ER diagram examples

ER diagram, Zombie Mermaid CUSTOMER PK int id string name UK string email date created_at
ER: Entity with Attributes
ER diagram, Zombie Mermaid ORDER PK int id FK int customer_id UK string invoice_number decimal total date order_date string status
ER: Attribute Keys (PK, FK, UK)
ER diagram, Zombie Mermaid PERSON (no attributes) PASSPORT (no attributes) has
ER: Exactly One to Exactly One (||--||)
ER diagram, Zombie Mermaid CUSTOMER (no attributes) ORDER (no attributes) places
ER: Exactly One to Zero-or-Many
ER diagram, Zombie Mermaid SUPERVISOR (no attributes) EMPLOYEE (no attributes) manages
ER: Zero-or-One to One-or-Many
ER diagram, Zombie Mermaid TEACHER (no attributes) COURSE (no attributes) teaches
ER: One-or-More to Zero-or-Many