Mermaid template

ER Diagram

Entities, attributes, and cardinality for database schema design.

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erDiagram
    CUSTOMER ||--o{ ORDER : places
    ORDER ||--|{ ORDER_ITEM : contains
    PRODUCT ||--o{ ORDER_ITEM : "ordered in"
    CUSTOMER {
        string id PK
        string email UK
        string name
    }
    ORDER {
        string id PK
        string customer_id FK
        date placed_at
    }

Entity-relationship diagrams sketch a database schema: entities become tables, and the crow's-foot notation between them encodes cardinality — ||--o{ reads as one-to-many.

Attribute blocks list columns with types, and keys can be marked PK, FK, or UK.