ER Tool

A visual database schema explorer that generates Entity-Relationship diagrams from PostgreSQL or MySQL databases. Adding support for other databases is easy.

This project is the outcome of my long, unsuccessful, search for a simple yet effective tool for visualizing database schemas. I decided to give it a try and roll my own.

Overview mode:

Features

• (new) Search for strings in fields and table names
• (new) Dark in the diagram rendering
• Interactive table filrering (add/remove to the diagram)
• Remove long table prefixes
• Export diagrams as SVG/PNG/PDF
• Overview mode for large schemas
• Zoom and fit controls
• Command Line Interface
• Dark/Light mode support

Prerequisites

• Python 3.8+
• Graphviz (brew install graphviz on macOS)

Installation

1. Clone the repository:

git clone https://github.com/nkanellopoulos/ER_tool.git
cd ER_tool

2. Install dependencies:

pip install -r requirements.txt

Usage

To launch the (GUI) application:

python ER_Tool.py

Connect to your database:

• using the connection dialog
• environment variable:

export ER_DB_CONNECTION="postgresql://user:pass@host:port/dbname"

Keyboard Shortcuts (on macOS use Cmd instead of Ctrl)

• Ctrl+B: Open database connection dialog
• Ctrl+=: Zoom in
• Ctrl+-: Zoom out
• Ctrl+0: Fit view
• Ctrl+1: Reset zoom (100%)
• Ctrl+A: Select all tables
• Ctrl+D: Deselect all tables
• Ctrl+R: Refresh diagram
• Ctrl+S: Export diagram

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

License

MIT