GraphQL Schema to SQL DDL Converter

Transform GraphQL SDL schemas into relational SQL CREATE TABLE migrations with inverted nullability, enums, and foreign keys.

At a glance

GraphQL Schema to SQL DDL Converter is a free developer utility that transforms GraphQL SDL type declarations into relational SQL CREATE TABLE migrations. It accurately handles inverted nullability (! to NOT NULL), maps custom scalars, resolves nested object relations into foreign key constraints, and outputs PostgreSQL, MySQL, or SQLite DDL 100% client-side in browser memory.

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100% Client-Side GraphQL SDL to SQL DDL Converter

Zero Server Uploads

Transform GraphQL SDL schemas into relational SQL CREATE TABLE migrations with inverted nullability, custom scalars, enums, foreign keys, and topological sorting.

Local Browser Sandbox
Presets:
0 chars
Instant client-side compile 
-- Click "Generate SQL DDL" or choose a Preset above to view generated SQL migration.

Inverted Nullability Semantics

In GraphQL, fields without exclamation marks (field: Type) are nullable, while exclamation marks (field: Type!) enforce non-null. The engine accurately translates this inverted logic into SQL NOT NULL constraints.

Automatic Foreign Key Synthesis

Nested object references (such as author: User!) are normalized into relational foreign keys (author_id REFERENCES users(id)), while child lists (posts: [Post!]!) are omitted to preserve 3NF database design.

Topological Dependency Ordering

Tables are sorted topologically by their foreign key dependency tree before generation. Parent tables (like users) are always created before dependent child tables (like comments or posts), ensuring SQL migrations execute without foreign key reference errors.

Why Use This GraphQL Schema to SQL DDL Converter?

Converts GraphQL SDL types into relational SQL CREATE TABLE DDL migrations
Accurately maps inverted nullability (! to NOT NULL, unadorned to nullable)
Synthesizes nested object references into foreign key columns and constraints
Orders tables topologically so parent tables are created before child tables
Supports PostgreSQL, MySQL, and SQLite dialects with custom scalars and enums
100% client-side execution with complete privacy: zero server transmissions

How to Use GraphQL Schema to SQL DDL Converter

1

Paste GraphQL SDL

Paste your GraphQL SDL type and enum definitions into the editor or pick a preset.

2

Configure SQL Dialect

Select PostgreSQL, MySQL, or SQLite, and configure Primary Key format and table naming.

3

Copy or Download SQL

Copy the generated SQL migration DDL or download as a .sql file immediately.

GraphQL SDL to SQL DDL Conversion example

Demonstrates topological ordering (users created before posts), inverted nullability (NOT NULL on required fields, bio nullable), and foreign key synthesis from author: User! to author_id REFERENCES users(id).

GraphQL SDL Source 
type User {
  id: ID!
  name: String!
  email: String!
  bio: String
}

type Post {
  id: ID!
  title: String!
  content: String!
  author: User!
}
SQL DDL (PostgreSQL) Processed 
CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  name VARCHAR(255) NOT NULL,
  email VARCHAR(255) NOT NULL,
  bio TEXT
);

CREATE TABLE posts (
  id SERIAL PRIMARY KEY,
  title VARCHAR(255) NOT NULL,
  content TEXT NOT NULL,
  author_id INTEGER REFERENCES users(id) NOT NULL
);

Technical Specifications & Engine Details

Technical specifications and engine details for GraphQL Schema to SQL DDL Converter
Specification Details
Supported Formats GRAPHQL, TEXT → SQL, TEXT
Execution Mode 100% Client-Side In-Browser (client)
Browser Requirements Modern browser with ES2020 JavaScript support.
Performance Constraints Pure client-side conversion. Root query, mutation, and subscription types are ignored; relational tables reflect data entities.
Maintained by Pragyan Pahadi

100% Client-Side Privacy Guarantee

Your GraphQL schema remains strictly on your local device. Zero data is transmitted to external servers.

Frequently Asked Questions

How does inverted nullability work between GraphQL and SQL?
In GraphQL SDL, fields are nullable by default and required only when marked with an exclamation mark (!). SQL CREATE TABLE reverses this convention: columns are nullable by default unless constrained with NOT NULL. The generator maps field: Type! to NOT NULL and unadorned field: Type to standard nullable SQL columns.
How are relationships and foreign keys handled in the generated SQL?
When a GraphQL type references another type (e.g. author: User!), the generator synthesizes a foreign key column (author_id) referencing the target table. When a field is a list of object types (e.g. posts: [Post!]!), the column is omitted on the parent table following 3NF relational database normalization.
Is my GraphQL schema data kept private?
Yes, 100%. All parsing, type mapping, and SQL generation occur entirely within your browser's local JavaScript runtime. No code is transmitted to any external server.

Methodology

This tool runs entirely in your browser. The example above shows a representative input and the result it produces.

Last updated .

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