Free Online ER Diagram Generator
Paste your CREATE TABLE DDL and instantly generate an entity-relationship diagram. Visualize your database schema with tables, columns, primary keys, and foreign key relationships — all in your browser, 100% free.
Generate ER Diagram NowWhy Use a Free ER Diagram Generator?
An entity-relationship (ER) diagram is the most intuitive way to understand a database schema. But traditional ER diagram tools require installation, signups, or expensive licenses. Our free online ER diagram generator solves this by working entirely in your browser:
Zero Setup
No installs or accounts. Just paste DDL and generate.
100% Private
Everything runs client-side. Your schema never leaves your machine.
Export PNG
Download your diagram as an image for docs or presentations.
FK Detection
Foreign keys are automatically parsed and drawn as relationship lines.
How It Works
1. Paste Your CREATE TABLE DDL
Copy your CREATE TABLE statements from any database or SQL script. The tool accepts standard SQL DDL syntax used by MySQL, PostgreSQL, SQLite, and more.
CREATE TABLE users ( id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(100) NOT NULL, email VARCHAR(255) UNIQUE NOT NULL, created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ); CREATE TABLE orders ( id INT PRIMARY KEY AUTO_INCREMENT, user_id INT NOT NULL, total DECIMAL(10,2), FOREIGN KEY (user_id) REFERENCES users(id) );
2. Click Generate
Press the Generate Diagram button and the parser extracts each table's columns, data types, primary keys, and foreign key references. The tool supports both inline PRIMARY KEY constraints and table-level PRIMARY KEY declarations.
3. Explore Your Schema
Each table appears as a color-coded card showing its columns with types. Primary keys are marked with a PK badge, foreign keys with an FK badge. Relationship lines connect foreign key columns to their referenced tables. Use the Zoom controls to adjust the view and Export as PNG to save the diagram.
Feature Highlights
- Multi-table support — Parse any number of CREATE TABLE statements in one go. Tables are automatically laid out in a readable grid.
- Primary key detection — Both inline (id INT PRIMARY KEY) and table-level (PRIMARY KEY (id, user_id)) constraints are recognized and highlighted.
- Foreign key mapping — FOREIGN KEY (col) REFERENCES table(col) constraints are drawn as curved, color-coded relationship lines with arrows.
- Column type display — Each column shows its data type (INT, VARCHAR, DECIMAL, TIMESTAMP, etc.) and nullable status.
- Built-in examples — Try predefined schemas for an e-commerce store, blog platform, or library management system to see how the tool works.
- PNG export — Download your ER diagram as a PNG image for inclusion in documentation, presentations, or architecture diagrams.
Use Cases
Database Design & Review
When designing a new database schema, quickly visualize your CREATE TABLE statements to spot missing foreign keys, redundant tables, or normalization issues. The ER diagram generator gives you instant visual feedback on your schema design.
Legacy Database Documentation
Reverse-engineer an existing database by exporting its DDL and pasting it into the tool. The generated ER diagram serves as up-to-date documentation without manual drawing — perfect for onboarding new team members onto an unfamiliar schema.
Interview & Study Preparation
When practicing database design for interviews or studying SQL schema design patterns, use the ER diagram generator to visualize your design and verify relationships between tables. Try schema patterns like many-to-many junction tables, self-referential hierarchies, and polymorphic associations.
Frequently Asked Questions
How do I generate an ER diagram from SQL for free?
Paste your CREATE TABLE statements into the free online ER diagram generator at sqlformat.io and click Generate Diagram. The tool parses your DDL, extracts tables, columns, primary keys, and foreign keys, then renders an interactive entity-relationship diagram. No signup or registration required.
What SQL dialects does the ER diagram generator support?
The tool supports standard SQL DDL syntax used by MySQL, PostgreSQL, SQLite, MariaDB, and most relational databases. It handles inline PRIMARY KEY constraints, table-level PRIMARY KEY declarations, FOREIGN KEY references with ON DELETE and ON UPDATE clauses, AUTO_INCREMENT and SERIAL types, DEFAULT values, NOT NULL constraints, and UNIQUE constraints.
Can I save or export my database ER diagram?
Yes. The free ER diagram generator includes an Export as PNG button that downloads the current diagram as a PNG image file. You can also use the Zoom controls to adjust the view before exporting. The diagram is rendered on an HTML5 Canvas element for crisp output.
Is my schema data private when using the online ER diagram generator?
Absolutely. All DDL parsing and diagram rendering happens client-side in your browser. Your database schema definitions never leave your device. There is no server-side processing, no logging, and no data collection of any kind.
How many tables can the ER diagram generator handle?
The online ER diagram generator can visualize any number of CREATE TABLE statements in a single input. Tables are automatically laid out in a grid arrangement with color-coded headers. Foreign key relationships between any two tables are drawn as curved connecting lines with arrow indicators.
Can I generate an ER diagram from a database dump or a live database connection?
Dumps yes, live connections no. Paste the output of SHOW CREATE TABLE in MySQL, pg_dump --schema-only in PostgreSQL, .schema in SQLite, or the Generate Scripts export from SSMS straight into the generator, because CREATE TABLE statements are all it parses. The tool never opens a database connection, which is exactly why it is safe to run against a production schema dump.
How is this different from dbdiagram.io, MySQL Workbench or Lucidchart?
Those tools expect you to learn a DSL, install a desktop client or create an account. This free online ER diagram generator takes the CREATE TABLE DDL you already have and renders it in your browser with no signup, no install and no upload. Desktop modelers still win for live schema editing and Lucidchart for hand-drawn presentation diagrams; this tool covers the everyday case of "here is my DDL, show me the schema".