Bun SQLite
Use this skill when working with SQLite databases using Bun's built-in, high-performance SQLite driver.
Key Concepts
Opening a Database
Bun includes a native SQLite driver:
import { Database } from "bun:sqlite";
// Open or create database
const db = new Database("mydb.sqlite");
// In-memory database
const memDb = new Database(":memory:");
// Read-only database
const readOnlyDb = new Database("mydb.sqlite", { readonly: true });Basic Queries
Execute SQL queries:
import { Database } from "bun:sqlite";
const db = new Database("mydb.sqlite");
// Create table
db.run(`
CREATE TABLE IF NOT EXISTS users (
id INTEGER PRIMARY KEY AUTOINCREMENT,
name TEXT NOT NULL,
email TEXT UNIQUE NOT NULL,
created_at DATETIME DEFAULT CURRENT_TIMESTAMP
)
`);
// Insert data
db.run("INSERT INTO users (name, email) VALUES (?, ?)", ["Alice", "alice@example.com"]);
// Query data
const users = db.query("SELECT * FROM users").all();
console.log(users);
// Close database
db.close();Prepared Statements
Use prepared statements for better performance:
import { Database } from "bun:sqlite";
const db = new Database("mydb.sqlite");
// Prepare statement
const insertUser = db.prepare("INSERT INTO users (name, email) VALUES (?, ?)");
// Execute multiple times
insertUser.run("Alice", "alice@example.com");
insertUser.run("Bob", "bob@example.com");
// Prepared query
const findUser = db.prepare("SELECT * FROM users WHERE email = ?");
const user = findUser.get("alice@example.com");
console.log(user);Best Practices
Use Prepared Statements
Prepared statements are faster and prevent SQL injection:
// Good - Prepared statement
const stmt = db.prepare("SELECT * FROM users WHERE id = ?");
const user = stmt.get(userId);
// Bad - String interpolation (SQL injection risk)
const user = db.query(`SELECT * FROM users WHERE id = ${userId}`).get();Transactions
Use transactions for atomic operations:
import { Database } from "bun:sqlite";
const db = new Database("mydb.sqlite");
// Transaction with automatic rollback on error
const insertUsers = db.transaction((users: Array<{ name: string; email: string }>) => {
const insert = db.prepare("INSERT INTO users (name, email) VALUES (?, ?)");
for (const user of users) {
insert.run(user.name, user.email);
}
});
try {
insertUsers([
{ name: "Alice", email: "alice@example.com" },
{ name: "Bob", email: "bob@example.com" },
]);
console.log("All users inserted");
} catch (error) {
console.error("Transaction failed:", error);
}Query Methods
Different methods for different use cases:
const db = new Database("mydb.sqlite");
// .all() - Get all rows
const allUsers = db.query("SELECT * FROM users").all();
// .get() - Get first row
const firstUser = db.query("SELECT * FROM users").get();
// .values() - Get array of arrays
const userValues = db.query("SELECT name, email FROM users").values();
// .run() - Execute without returning rows
db.run("DELETE FROM users WHERE id = ?", [userId]);Error Handling
Properly handle database errors:
import { Database } from "bun:sqlite";
try {
const db = new Database("mydb.sqlite");
const stmt = db.prepare("INSERT INTO users (name, email) VALUES (?, ?)");
stmt.run("Alice", "alice@example.com");
db.close();
} catch (error) {
if (error instanceof Error) {
console.error("Database error:", error.message);
}
}Common Patterns
CRUD Operations
import { Database } from "bun:sqlite";
interface User {
id?: number;
name: string;
email: string;
created_at?: string;
}
class UserRepository {
private db: Database;
constructor(dbPath: string) {
this.db = new Database(dbPath);
this.createTable();
}
private createTable() {
this.db.run(`
CREATE TABLE IF NOT EXISTS users (
id INTEGER PRIMARY KEY AUTOINCREMENT,
name TEXT NOT NULL,
email TEXT UNIQUE NOT NULL,
created_at DATETIME DEFAULT CURRENT_TIMESTAMP
)
`);
}
create(user: User): User {
const stmt = this.db.prepare("INSERT INTO users (name, email) VALUES (?, ?) RETURNING *");
return stmt.get(user.name, user.email) as User;
}
findById(id: number): User | null {
const stmt = this.db.prepare("SELECT * FROM users WHERE id = ?");
return (stmt.get(id) as User) || null;
}
findAll(): User[] {
return this.db.query("SELECT * FROM users").all() as User[];
}
update(id: number, user: Partial<User>): User | null {
const stmt = this.db.prepare(`
UPDATE users
SET name = COALESCE(?, name), email = COALESCE(?, email)
WHERE id = ?
RETURNING *
`);
return (stmt.get(user.name, user.email, id) as User) || null;
}
delete(id: number): boolean {
const stmt = this.db.prepare("DELETE FROM users WHERE id = ?");
const result = stmt.run(id);
return result.changes > 0;
}
close() {
this.db.close();
}
}
// Usage
const users = new UserRepository("mydb.sqlite");
const newUser = users.create({ name: "Alice", email: "alice@example.com" });
console.log(newUser);Bulk Inserts with Transaction
import { Database } from "bun:sqlite";
const db = new Database("mydb.sqlite");
const bulkInsert = db.transaction((items: Array<{ name: string; email: string }>) => {
const stmt = db.prepare("INSERT INTO users (name, email) VALUES (?, ?)");
for (const item of items) {
stmt.run(item.name, item.email);
}
});
// Insert 1000 users atomically
const users = Array.from({ length: 1000 }, (_, i) => ({
name: `User ${i}`,
email: `user${i}@example.com`,
}));
bulkInsert(users);Migrations
import { Database } from "bun:sqlite";
class DatabaseMigration {
private db: Database;
constructor(dbPath: string) {
this.db = new Database(dbPath);
this.initMigrationTable();
}
private initMigrationTable() {
this.db.run(`
CREATE TABLE IF NOT EXISTS migrations (
id INTEGER PRIMARY KEY AUTOINCREMENT,
name TEXT NOT NULL,
applied_at DATETIME DEFAULT CURRENT_TIMESTAMP
)
`);
}
private hasRun(name: string): boolean {
const stmt = this.db.prepare("SELECT COUNT(*) as count FROM migrations WHERE name = ?");
const result = stmt.get(name) as { count: number };
return result.count > 0;
}
private recordMigration(name: string) {
this.db.run("INSERT INTO migrations (name) VALUES (?)", [name]);
}
migrate(name: string, sql: string) {
if (this.hasRun(name)) {
console.log(`Migration ${name} already applied`);
return;
}
const migration = this.db.transaction(() => {
this.db.run(sql);
this.recordMigration(name);
});
migration();
console.log(`Migration ${name} applied successfully`);
}
close() {
this.db.close();
}
}
// Usage
const migration = new DatabaseMigration("mydb.sqlite");
migration.migrate(
"001_create_users",
`
CREATE TABLE users (
id INTEGER PRIMARY KEY AUTOINCREMENT,
name TEXT NOT NULL,
email TEXT UNIQUE NOT NULL
)
`
);
migration.migrate(
"002_add_timestamps",
`
ALTER TABLE users ADD COLUMN created_at DATETIME DEFAULT CURRENT_TIMESTAMP
`
);
migration.close();Query Builder Pattern
import { Database } from "bun:sqlite";
class QueryBuilder<T> {
private db: Database;
private tableName: string;
private whereClause: string[] = [];
private whereValues: any[] = [];
private limitValue?: number;
private offsetValue?: number;
constructor(db: Database, tableName: string) {
this.db = db;
this.tableName = tableName;
}
where(column: string, value: any): this {
this.whereClause.push(`${column} = ?`);
this.whereValues.push(value);
return this;
}
limit(n: number): this {
this.limitValue = n;
return this;
}
offset(n: number): this {
this.offsetValue = n;
return this;
}
getAll(): T[] {
let sql = `SELECT * FROM ${this.tableName}`;
if (this.whereClause.length > 0) {
sql += ` WHERE ${this.whereClause.join(" AND ")}`;
}
if (this.limitValue) {
sql += ` LIMIT ${this.limitValue}`;
}
if (this.offsetValue) {
sql += ` OFFSET ${this.offsetValue}`;
}
const stmt = this.db.prepare(sql);
return stmt.all(...this.whereValues) as T[];
}
getOne(): T | null {
let sql = `SELECT * FROM ${this.tableName}`;
if (this.whereClause.length > 0) {
sql += ` WHERE ${this.whereClause.join(" AND ")}`;
}
sql += " LIMIT 1";
const stmt = this.db.prepare(sql);
return (stmt.get(...this.whereValues) as T) || null;
}
}
// Usage
interface User {
id: number;
name: string;
email: string;
}
const db = new Database("mydb.sqlite");
const query = new QueryBuilder<User>(db, "users");
const users = query.where("name", "Alice").limit(10).getAll();
console.log(users);Anti-Patterns
Don't Use String Interpolation
// Bad - SQL injection vulnerability
const userId = "1 OR 1=1";
const user = db.query(`SELECT * FROM users WHERE id = ${userId}`).get();
// Good - Use prepared statements
const stmt = db.prepare("SELECT * FROM users WHERE id = ?");
const user = stmt.get(userId);Don't Forget to Close Database
// Bad - Database remains open
const db = new Database("mydb.sqlite");
db.run("INSERT INTO users (name, email) VALUES (?, ?)", ["Alice", "alice@example.com"]);
// Good - Close when done
const db = new Database("mydb.sqlite");
try {
db.run("INSERT INTO users (name, email) VALUES (?, ?)", ["Alice", "alice@example.com"]);
} finally {
db.close();
}Don't Use Transactions for Single Operations
// Bad - Unnecessary transaction
const insert = db.transaction(() => {
db.run("INSERT INTO users (name, email) VALUES (?, ?)", ["Alice", "alice@example.com"]);
});
insert();
// Good - Direct execution
db.run("INSERT INTO users (name, email) VALUES (?, ?)", ["Alice", "alice@example.com"]);Don't Reparse Queries
// Bad - Reparsing query each iteration
for (let i = 0; i < 1000; i++) {
db.run("INSERT INTO users (name, email) VALUES (?, ?)", [`User ${i}`, `user${i}@example.com`]);
}
// Good - Prepare once, execute many times
const stmt = db.prepare("INSERT INTO users (name, email) VALUES (?, ?)");
for (let i = 0; i < 1000; i++) {
stmt.run(`User ${i}`, `user${i}@example.com`);
}Related Skills
- bun-runtime: Core Bun runtime features and file I/O
- bun-testing: Testing database operations
- bun-bundler: Bundling applications with SQLite