ER Diagram Generator
FreeGenerate entity-relationship diagrams from schema input
- posts.user_id→users.id
- comments.post_id→posts.id
- comments.author_id→users.id
erDiagram
USERS {
INTEGER id PK
TEXT name
TEXT email
}
POSTS {
INTEGER id PK
INTEGER user_id FK
TEXT title
TEXT body
}
COMMENTS {
INTEGER id PK
INTEGER post_id FK
INTEGER author_id FK
TEXT text
}
POSTS }o--|| USERS : "user_id"
COMMENTS }o--|| POSTS : "post_id"
COMMENTS }o--|| USERS : "author_id"About ER Diagram Generator
A database schema is far easier to reason about as a picture than as a wall of CREATE TABLE statements. When you are onboarding to a project, planning a migration, or documenting a system, an entity-relationship diagram shows tables, fields, and how they connect at a glance. The ER Diagram Generator turns your schema input into a visual diagram, laying out entities and the relationships between them so the overall shape of the data model becomes obvious.
Paste your schema and the tool renders an ER diagram you can review and reference. It runs entirely in your browser with no signup and no watermark, and your schema stays on your machine. That makes it a quick, private way to visualize a data model, whether you are sketching a new design or trying to understand one you just inherited, without opening a heavyweight modeling application.
Common uses
- Documenting an existing database visually for onboarding or a wiki.
- Reviewing how tables relate before planning a schema migration.
- Communicating a proposed data model to teammates in a design discussion.
- Spotting missing or awkward relationships by seeing the schema laid out.
- Understanding an unfamiliar database you just inherited from another team.
How to use
- 1
Configure options
Set your preferences using the options panel below.
- 2
Click Generate
Click the process button to generate your result instantly.
- 3
Copy or download
Copy the result to clipboard or download it directly to your device.
Why ToolHub?
- Generate queries instantly
- Support for multiple DB engines
- Schema visualization
FAQ
What schema format do I provide?
You supply your schema definition and the tool reads its entities and relationships to build the diagram.
Does it show relationships between tables?
Yes. The diagram draws entities along with the connections that link them, so foreign-key style relationships are visible.
Can it connect to my live database?
No. It builds the diagram from the schema you provide, which keeps your database access details private.
Is my schema uploaded anywhere?
No. Diagram generation runs in your browser, so your schema input stays on your device.
Can I use ER Diagram Generator on mobile?
Yes — ToolHub is fully responsive and works on iPhone, Android, tablets and all modern browsers. No app install needed.