SQL 2 ER

A command-line tool to convert SQL scripts into Entity-Relationship (ER) diagrams.
Designed to work with PostgreSQL syntax.
Report a Bug · Request a Feature

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Table of Contents

• Example
• Getting Started
• Built With
• Roadmap
• Limitations
• Unsupported Features
• Acknowledgments

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Checkout web version powered by WebAssembly

Example

Input: test.sql

begin;

create table users (
	user_id serial primary key
  , user_name varchar(255) not null unique
  , email varchar(255) not null unique
  , password text not null
  , created_at timestamptz default now()
  , updated_at timestamptz default now()
);

create table user_profile_image (
	user_id int references users on delete cascade primary key
 ,  user_profile_image text not null
 ,  created_at timestamptz default now()
 ,  updated_at timestamptz default now()
);
...

Command:

./sql2er-exe test.sql -o erd.jpeg

Output:

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Getting Started

Option 1: Download Binary

1. Download the binary from the Releases page.

2. Run the tool:

   ./sql2er-exe test.sql -o erd.jpeg

Option 2: Build from Source

1. Install Stack via GHCup.

2. Clone the repository and navigate to the project root.

3. Build the binary for linux:

   stack build
   cp $(stack path --local-install-root)/bin/sql2er-exe .
   ./sql2er-exe test.sql -o erd.jpeg

Option 3: Build WASM

1. Install wasm32-wasi-cabal from here
2. Make sure to download the 9.8 FLAVOUR.

wasm32-wasi-cabal build sql2er-wasm -f build-sql2er-wasm
cp path/to/sql2er-wasm.wasm .
python3 -m http.server

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Built With

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Roadmap

• Add Changelog
• Add Test Cases
• Support GENERATED Constraint
• Gracefully Ignore Partitions
• Support bigserial
• Add Additional Examples
• Enhance Documentation
• Add More Parsing Functions
• Support Interval Data Type
• Support 2D Arrays

For the full list of proposed features and known issues, check out the open issues.

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Limitations

• Needs internet connection since, We are sending request to mermaid API.
• Syntax Validation:
  The parser doesn't validate SQL syntax; it extracts only the necessary information for generating ER diagrams.
• PostgreSQL Specific:
  Designed and tested using PostgreSQL 17.

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Unsupported Features

• DETACH
• USING ...
• TABLESPACE
• NOT VALID
• VALIDATE
• INTERVAL Data Type

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Acknowledgments

This project was inspired by sqldiagram, which focuses on MySQL but lacked robust parsing capabilities.

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