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PostgreSQL to ER Diagram

Q: How do I turn a Postgres database into an ER diagram?

Run pg_dump --schema-only and paste the output. Tables and foreign keys (including those added via ALTER TABLE) are drawn automatically.

Paste your PostgreSQL schema — CREATE TABLE statements or a pg_dump — and get an interactive ER diagram with every table, column and foreign key drawn for you.

Open the diagram tool →

No signup · nothing uploaded · export PNG / SVG / Mermaid / DBML · shareable link

ER diagram of the PostgreSQL example schema: customers and orders (2 tables, 1 relationship) — The PostgreSQL example below, drawn by the tool: customers and orders (2 tables, 1 relationship).

At a glance

What it is: SQL to ER Diagram is a free, open-source browser tool that turns a PostgreSQL schema into an interactive entity-relationship (ER) diagram.
Input: PostgreSQL CREATE TABLE and ALTER TABLE statements, or the output of pg_dump --schema-only.
Output: An interactive ER diagram you can rearrange, then export as PNG, SVG, Mermaid, DBML or PlantUML, or share as a link.
Cost: Free. MIT-licensed open source. No account or signup.
Privacy: Runs entirely in your browser. The schema is never uploaded, and share links carry the diagram in the URL fragment, which is not sent to a server.
Limits: It never connects to your database itself: you paste schema text, or run one read-only catalog query in your own client and paste the result. There are no accounts, so there is no real-time multi-user editing; diagrams are kept in your browser, as a saved file, or as a share link. Layout stays smooth at around 300 tables.

How it works

Dump the schema with pg_dump --schema-only your_db, or copy your CREATE TABLE statements.
Paste it into the editor — Postgres is parsed automatically, including ALTER TABLE … ADD CONSTRAINT foreign keys.
Tables render with columns and types; relations are drawn from the constraints.
Arrange, hide tables, then export PNG/SVG or share a link.

Example

A PostgreSQL schema like this:

CREATE TABLE customers (
  id SERIAL PRIMARY KEY,
  email TEXT NOT NULL UNIQUE
);

CREATE TABLE orders (
  id SERIAL PRIMARY KEY,
  customer_id INTEGER NOT NULL REFERENCES customers(id)
);

…renders two tables with a relation from orders.customer_id → customers.id. Try it with your own →

Guide

Postgres is the dialect people have the most trouble diagramming, for one reason: pg_dump doesn't put foreign keys where you expect. It emits each table with ALTER TABLE ONLY orders ADD CONSTRAINT orders_customer_id_fkey FOREIGN KEY (customer_id) REFERENCES customers(id) — sometimes thousands of lines away from the CREATE TABLE. This parser collects those ALTER TABLE statements and stitches them back onto the right tables, so a full pg_dump --schema-only paste comes out complete.

Postgres features the parser understands

SERIAL, BIGSERIAL, GENERATED … AS IDENTITY, and GENERATED ALWAYS AS (…) STORED columns.
Schema-qualified names — public.customers is shown as customers.
CREATE TYPE … AS ENUM usage on columns, arrays like TEXT[], JSONB, UUID, TIMESTAMPTZ.
Composite primary keys via PRIMARY KEY (a, b), and ON DELETE CASCADE actions.

Only need one schema from a multi-schema database? Filter the dump first: pg_dump --schema-only --no-owner --no-privileges -n myschema your_db. The smaller paste renders faster and the diagram stays readable.

Why use it

Private: everything runs in your browser — nothing is uploaded or stored on a server.
pg_dump-friendly — handles ALTER TABLE ONLY … ADD CONSTRAINT foreign keys.
Interactive: drag tables, auto-arrange, hide noise, add notes, and manually link columns.
Export a high-res PNG, vector SVG, or the schema as Mermaid / DBML / PlantUML code.
Free & open source — no account, no sign-up.

PostgreSQLpg_dumpMySQLSQLitePrisma

FAQ

How do I turn a Postgres database into an ER diagram?

Run pg_dump --schema-only and paste the output. Tables and foreign keys (including those added via ALTER TABLE) are drawn automatically.

Does it support pg_dump?

Yes — pg_dump emits foreign keys as separate ALTER TABLE statements, which are parsed and turned into relations.

Is my schema uploaded anywhere?

No. Everything runs locally in your browser — your schema is never uploaded to or stored on any server.

Can I export the diagram?

Yes — export a high-resolution PNG or vector SVG, copy the schema as Mermaid, DBML or PlantUML, or share a link that encodes the whole diagram in the URL.

Is it free?

Yes. It is completely free and open source, with no account or sign-up required.