A5:ER Tools for VS Code

A powerful Visual Studio Code extension for working with A5:ER (Entity Relationship) database design files. This extension provides preview capabilities and seamless conversion between A5:ER format and JSON format, making it easier to work with AI/LLM tools for database design assistance.

Features

🔍 A5:ER File Preview

Visual preview of A5:ER files directly in VS Code
Entity-Relationship diagram visualization
Table structure display with fields, types, and constraints
Real-time preview updates as you edit

🔄 Format Conversion

A5:ER to JSON: Convert A5:ER files to structured JSON format for easy processing by AI/LLM tools
JSON to A5:ER: Convert JSON back to A5:ER format to maintain compatibility with A5:SQL tools
Preserves all metadata including:
- Entity names (logical and physical)
- Field definitions with data types
- Primary key and foreign key relationships
- Default values and comments
- Entity positioning information
- Relationship mappings

🤖 AI/LLM Integration Ready

The JSON format is specifically designed to be easily readable and processable by Large Language Models, enabling:

Database schema analysis
Automated documentation generation
Schema optimization suggestions
Code generation from database design

Installation

From VS Code Marketplace

Open VS Code
Go to Extensions (Ctrl+Shift+X)
Search for "pengent-a5er-tools"
Click Install

From VSIX File

Download the .vsix file from releases
Open VS Code
Press Ctrl+Shift+P to open Command Palette
Type "Extensions: Install from VSIX..."
Select the downloaded .vsix file

Usage

Preview A5:ER Files

Open any .a5er file in VS Code
Right-click in the editor and select "Preview A5er File"
- Or press Ctrl+Shift+P and type "Preview A5er File"
A preview panel will open showing the entity-relationship diagram

Convert A5:ER to JSON

Open a .a5er file in VS Code
Right-click and select "Convert A5:ER to A5ER.JSON"
- Or use Command Palette: Ctrl+Shift+P → "Convert A5:ER to A5ER.JSON"
A new .a5er.json file will be created and opened alongside your original file

Convert JSON back to A5:ER

Open a .a5er.json file in VS Code
Right-click and select "Convert A5ER.JSON to A5:ER"
- Or use Command Palette: Ctrl+Shift+P → "Convert A5ER.JSON to A5:ER"
A new .a5er file will be generated

JSON Format Structure

The converted JSON follows this structure:

{
  "project": {
    "name": "Project Name",
    "author": "Author Name",
    "rdbms": "Database Type"
  },
  "entities": [
    {
      "name": "table_name",
      "logical_name": "テーブル名",
      "fields": [
        {
          "name": "field_name",
          "logical_name": "フィールド名",
          "type": "VARCHAR(50)",
          "not_null": true,
          "pk": false,
          "default": "default_value",
          "comment": "Field description"
        }
      ],
      "position": {
        "page": "Main",
        "left": 100,
        "top": 200
      }
    }
  ],
  "relations": [
    {
      "from": "parent_table",
      "to": "child_table",
      "from_field": "id",
      "to_field": "parent_id",
      "type": "1:N"
    }
  ]
}

Supported A5:ER Features

✅ Fully Supported:

Entity definitions (logical and physical names)
Field definitions with all data types
Primary key constraints
Foreign key relationships
Default values
Field comments
Entity positioning
Project metadata

⚠️ Partially Supported:

Complex relationship types (converted to standard 1:N, N:1 format)
Advanced A5:ER formatting options

Use Cases

Database Documentation

Convert your A5:ER files to JSON and use AI tools to generate comprehensive documentation:

# Example workflow
1. Convert schema.a5er → schema.a5er.json
2. Process with AI/LLM for documentation
3. Generate markdown/HTML documentation

Schema Analysis

Use the JSON format for automated analysis:

Identify naming convention violations
Find missing foreign key relationships
Detect potential performance issues
Generate test data schemas

Code Generation

Convert database designs to application code:

Generate ORM models
Create API endpoints
Build database migration scripts
Generate CRUD operations

Requirements

Visual Studio Code 1.101.0 or higher
A5:ER files created with A5:SQL Mk-2 or compatible tools

Extension Settings

This extension contributes the following settings:

Currently no configurable settings. Settings will be added in future versions based on user feedback.

Known Issues

Large A5:ER files (>1000 entities) may experience slower preview rendering
Complex nested relationships might not display perfectly in preview mode
Unicode characters in Japanese field names display correctly in JSON but may have encoding issues in some environments

Release Notes

0.0.1

Initial release
A5:ER file preview functionality
Bidirectional A5:ER ↔ JSON conversion
Context menu integration
Command palette support

Contributing

We welcome contributions! Please see our Contributing Guidelines for details.

Development Setup

Clone the repository
Run npm install to install dependencies
Press F5 to open a new Extension Development Host window
Test your changes

License

This project is licensed under the MIT License - see the LICENSE file for details.

Support

🐛 Bug Reports: GitHub Issues
💡 Feature Requests: GitHub Discussions
📧 Email: support@your-domain.com

Acknowledgments

A5:SQL Mk-2 by m.matsubara for the original A5:ER format specification
VS Code team for the excellent extension API
The open-source community for inspiration and feedback

Made with ❤️ for database designers and developers

pengent-a5er-tools

PengentAI(RyohYA)