What is SQL to better-sqlite3 Types Generator?
better-sqlite3 is a high-performance synchronous SQLite3 driver for Node.js that operates entirely in-process without a separate database server. Unlike async SQLite libraries, better-sqlite3 executes queries synchronously, which eliminates callback complexity and makes it ideal for Electron desktop apps, CLI tools, game servers, and any Node.js application that needs an embedded database. This converter transforms your SQL CREATE TABLE statements into TypeScript interfaces that align with better-sqlite3's type parameter system, producing row types, a DatabaseSchema interface, optional insert types that handle auto-increment and default columns, and helper functions for common CRUD operations.
How to Use
- Write or paste your SQL CREATE TABLE statements into the left panel — SQLite-specific syntax like AUTOINCREMENT and datetime('now') is fully supported
- Toggle "Include Insert types" to generate separate interfaces where auto-increment and default-valued columns become optional
- Toggle "Include helper functions" to produce typed getById, getAll, and insert functions for each table
- Click "Generate better-sqlite3 Types" and review the output on the right
- Copy the generated TypeScript code into your project and import it alongside better-sqlite3
Why Use This Tool?
Tips & Best Practices
- SQLite uses INTEGER PRIMARY KEY as the auto-increment pattern rather than a dedicated SERIAL type — the converter detects this automatically
- When using the DatabaseSchema type parameter, better-sqlite3 will infer the return type of .prepare().get() based on the table name in your query string
- Store dates as ISO 8601 TEXT in SQLite for best compatibility — the converter maps TIMESTAMP and DATE columns to string by default
- For JSON columns, the converter outputs unknown since SQLite has no native JSON type — cast or validate at runtime with a schema validator like Zod
Frequently Asked Questions
How does the type mapping work for SQLite columns?
SQLite uses type affinity rather than strict types. The converter follows SQLite affinity rules: INTEGER-family types map to number, TEXT-family types map to string, REAL maps to number, BLOB maps to Buffer, and BOOLEAN maps to number (since SQLite stores booleans as 0/1). Nullable columns get union types like string | null.
When should I avoid using better-sqlite3?
Avoid better-sqlite3 in scenarios requiring non-blocking I/O at scale, such as high-concurrency web servers handling thousands of simultaneous requests. Because it is synchronous, long-running queries will block the event loop. For those cases, consider an async driver like sql.js or a client-server database like PostgreSQL.
What is the DatabaseSchema interface for?
DatabaseSchema maps each table name to its corresponding row type interface. When you create a database instance with new BetterSqlite3.Database<DatabaseSchema>(), better-sqlite3 can infer the return type of queries based on the table name referenced in your SQL string, giving you compile-time type safety.
What are Insert types and why are they separate?
Insert types are variants of row types where auto-increment columns (INTEGER PRIMARY KEY) and columns with DEFAULT values are marked as optional. This reflects the data you actually provide in an INSERT statement — you do not supply the id or columns that the database fills automatically.
Is my SQL data sent to a server?
No. All parsing and code generation happens entirely in your browser using a client-side regex parser. Your SQL schema never leaves your device, and no network requests are made during the conversion.
Real-world Examples
Electron app with typed SQLite access
An Electron note-taking app stores notes in a local SQLite database. The developer pastes their SQL schema into this tool, generates row and insert types, and uses them with better-sqlite3 to get full autocompletion when querying notes and inserting new records.
CREATE TABLE notes (
id INTEGER PRIMARY KEY AUTOINCREMENT,
title TEXT NOT NULL,
body TEXT,
pinned INTEGER DEFAULT 0,
created_at TEXT DEFAULT (datetime('now'))
);export interface NotesRow {
id: number;
title: string;
body: string | null;
pinned: number;
created_at: string;
}CLI tool with helper functions
A Node.js CLI tool manages a local SQLite database of bookmarks. By enabling the helper functions option, the developer gets typed getById, getAll, and insert functions that eliminate manual type casting in every query.