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SQL to JSON Schema Generator

SQL DDL (CREATE TABLE)

JSON Schema Draft-07 Output

 
 
 
 
  
   
  
 
 
 
   
How ZeroData protects your privacy

 
 
 
     
  •  ✓ No Uploads: Processing happens entirely via client-side JavaScript. 
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  •  ✓ No Storage: We do not have a database. We physically cannot save your data. 
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  •  ✓ No Tracking: We don't log what you process or track your inputs. 
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  •  ✓ Verifiable: Check your DevTools Network tab. You will see 0 outbound requests. 
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The SQL to JSON Schema Generator is a powerful online tool designed for developers, database administrators, and API architects. With this tool, you can effortlessly transform raw SQL CREATE TABLE definitions into standard JSON Schema structures. This bridges the gap between relational databases and modern web APIs, where JSON Schema is extensively used for data validation. As part of our Comprehensive Database Tools Guide (Pillar Guide), this tool aims to streamline your database workflows.

 

Whether you are building REST API documentation, converting legacy applications, or writing validation rules for your frontend, manually converting SQL to JSON Schema is tedious and error-prone. Our tool handles data type mapping, recognizes NOT NULL constraints, and structures everything perfectly to Draft-07 specs.

 
How the Data Type Mapping Works
 

The tool uses an intelligent parsing algorithm to map SQL data types to valid JSON Schema types:

 
     
  • Integers (INT, SERIAL, BIGINT) map to "type": "integer".
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  • Decimals (DECIMAL, FLOAT, NUMERIC) map to "type": "number".
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  • Booleans (BOOLEAN, BOOL) map to "type": "boolean".
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  • Strings (VARCHAR, TEXT, CHAR) map to "type": "string".
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  • Dates (TIMESTAMP, DATE) map to "type": "string" with "format": "date-time" or "date".
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  • JSON (JSON, JSONB) maps to "type": "object".
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Need to validate deeper nested structures? Learn more in our complete guide to JSON schema validation.

 
Best Practices
 

When generating JSON schemas from SQL, ensure your DDL statements are syntactically valid and terminated with semicolons. If you are using this alongside other data formats, you might also find our SQL to JSON data converter useful for transforming actual row data. Always verify the required fields and ensure the logical constraints of your schema match your application's expectations.

 
Troubleshooting
 

If your JSON schema is not generating correctly, check for missing commas or unclosed parentheses in your SQL CREATE TABLE statements. For advanced data types (like custom ENUMs), you may need to manually adjust the JSON schema after generation, as this tool primarily targets standard data types. Ensure your SQL does not contain complex triggers or unsupported functional constraints inside the column definitions. If parsing completely fails, try simplifying your SQL down to the core column declarations.

 
Privacy Explanation
 

Your data privacy is our top priority. This SQL to JSON Schema generator processes all data locally within your web browser. We do not track, store, or transmit your database schemas, table names, or structures to our servers.

 
Browser Compatibility
 

Our SQL to JSON Schema generator uses standard Web APIs and is fully functional on all modern web browsers including Google Chrome, Mozilla Firefox, Apple Safari, and Microsoft Edge. No additional plugins or downloads are required. Mobile browsers are also fully supported with an optimized layout for viewing and copying code on smaller screens.

 
  
  
 
How to Use the SQL to JSON Schema Generator
 
     
  1. Copy your SQL DDL (Data Definition Language) statements, specifically CREATE TABLE queries, from your database schema, migration files, or SQL client.
  2. Paste the SQL queries into the left-hand editor. The tool supports standard ANSI SQL syntax common across PostgreSQL, MySQL, SQL Server, and SQLite.
  3. The client-side parsing engine instantly analyzes your SQL, extracting table names, column names, data types, and primary key/not null constraints.
  4. Review the generated JSON Schema Draft-07 object in the right-hand output panel. It automatically maps SQL data types (like VARCHAR or TIMESTAMP) to JSON Schema equivalents.
  5. Click the 'Copy Output' button to copy the valid JSON schema. You can now use this directly in your REST APIs, frontend validation logic, or OpenAPI (Swagger) specifications.
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Common Use Cases
 
     
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     API Development: Automatically create JSON Schemas for validating incoming REST API request payloads based on your existing relational database tables. 
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     Database Migration: Assist in migrating legacy SQL schemas to NoSQL document databases (like MongoDB) by generating a baseline JSON structure. 
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     Documentation: Generate standard JSON-formatted models from your database DDL to share with frontend developers and external API consumers. 
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     Mock Data Generation: Use the resulting JSON Schema to power mock data generators (like Faker.js) that perfectly match your production database structure. 
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     OpenAPI Specifications: Accelerate the writing of Swagger or OpenAPI specs by quickly translating your SQL tables into reusable JSON schema components. 
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Frequently Asked Questions
 
 
 
Can this tool handle multiple tables at once?
 
Yes, if you paste multiple CREATE TABLE statements, the tool will output an array of JSON Schema objects, one for each parsed table.
 
 
Is my SQL data sent to a server?
 
No, all parsing and conversion happens entirely in your web browser locally. No data is sent across the network.
 
 
Which SQL dialects are supported?
 
The tool supports standard ANSI SQL syntax common across PostgreSQL, MySQL, SQL Server, and SQLite. It safely ignores dialect-specific constraints and focuses on column names, data types, and primary/not null constraints.
 
 
 
  
 
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