ERD Template

Use this template for Entity Relationship Diagrams (ERD) to document database schema.

When to Use

Create an ERD when:

• Designing database schema
• Documenting data model
• Planning schema migration

Template

@startuml
!include /plantuml/themes/puml-theme-x-light.puml

entity EntityName {
  * id : UUID <<PK>>
  --
  * field_name : Type
  field_name : Type <<nullable>>
  foreign_key_id : UUID <<FK>>
  created_at : DateTime
  updated_at : DateTime
}

entity RelatedEntity {
  * id : UUID <<PK>>
  --
  * name : String
}

EntityName }|--|| RelatedEntity : "relationship"
@enduml

Relationship Cardinality

• ||--|| : One to one
• }|--|| : Many to one
• ||--o{ : One to many
• }|--o{ : Many to many

Best Practices

• Primary Keys: Mark with <<PK>>
• Foreign Keys: Mark with <<FK>>
• Required Fields: Prefix with *
• Nullable Fields: Mark with <<nullable>>
• Timestamps: Include created_at and updated_at when applicable
• Relationship Notation: Use PlantUML relationship syntax
• Validation: Validate ERD against actual database schema

File Location

Place ERDs in: content/{project}/docs/architecture/erd/

Example: content/billing-system/docs/architecture/erd/payment-schema.mdx