Generate ER Diagrams

Generate Entity-Relationship diagrams from database schema documentation.

Steps

1. Load Configuration

Read .dt-workspace config and validate generatedPaths exists.

2. Select Target

If arguments provided, use them. Otherwise, use AskUserQuestion:

1. Select platform
2. Select module (or "all" for entire platform)

3. Select Format

If --format provided, use it. Otherwise, ask:

• mermaid (default) - GitHub/GitLab compatible
• plantuml - PlantUML syntax
• ascii - Text-based diagram

4. Read Database Schemas

For each selected module:

1. Read database-schema.md
2. Extract table definitions, columns, relationships

5. Generate Diagram

Mermaid Format:

erDiagram
    USER {
        uuid id PK
        string email UK
        string password_hash
        timestamp created_at
    }
    ORDER {
        uuid id PK
        uuid user_id FK
        decimal total
        string status
    }
    USER ||--o{ ORDER : places

PlantUML Format:

@startuml
entity User {
  * id : UUID <<PK>>
  --
  * email : VARCHAR(255) <<UK>>
  * password_hash : VARCHAR(255)
  created_at : TIMESTAMP
}
entity Order {
  * id : UUID <<PK>>
  --
  * user_id : UUID <<FK>>
  * total : DECIMAL
  status : VARCHAR(50)
}
User ||--o{ Order
@enduml

ASCII Format:

+----------------+       +----------------+
|     USER       |       |     ORDER      |
+----------------+       +----------------+
| id (PK)        |<----->| id (PK)        |
| email (UK)     |       | user_id (FK)   |
| password_hash  |       | total          |
| created_at     |       | status         |
+----------------+       +----------------+

6. Write Output

Create diagram file:

• <module>/er-diagram.md (contains diagram code block)
• Or append to existing database-schema.md

7. Display Summary

ER DIAGRAM GENERATED

Format: <format>
Module: <module>
Output: <path>/er-diagram.md

Tables: X
Relationships: Y

To view:
- Mermaid: Render in GitHub/GitLab or mermaid.live
- PlantUML: Use plantuml.com or IDE plugin
- ASCII: View directly in any text editor

Diagram Conversion

To convert between formats, specify source and target:

/dt-workspace:diagram --convert --from mermaid --to plantuml

Reads existing diagram and converts to new format.