How do I install the Bun SQLite skill?

Run npx skillmds@latest add jarle/bun-sqlite in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

What does the Bun SQLite skill do?

Bun natively implements a high-performance SQLite3 driver. It is listed under Coding & Dev Tools on SkillMD.

Is Bun SQLite safe to use?

This skill has not completed SkillMD's automated safety review yet. Capability flags: makes network calls. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Bun SQLite?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Bun SQLite free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Bun SQLite?

jarle (@jarle) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Bun SQLite by jarle — Agent Skill

Name: Bun SQLite
Rating: 4.2 (5 reviews)
Author: jarle

SQLite

Bun natively implements a high-performance SQLite3 driver.

Bun natively implements a high-performance SQLite3 driver. To use it import from the built-in bun:sqlite module.

import { Database } from "bun:sqlite";

const db = new Database(":memory:");
const query = db.query("select 'Hello world' as message;");
query.get();

{ message: "Hello world" }

The API is simple, synchronous, and fast. Credit to better-sqlite3 and its contributors for inspiring the API of bun:sqlite.

Features include:

Transactions
Parameters (named & positional)
Prepared statements
Datatype conversions (BLOB becomes Uint8Array)
Map query results to classes without an ORM - query.as(MyClass)
The fastest performance of any SQLite driver for JavaScript
bigint support
Multi-query statements (e.g. SELECT 1; SELECT 2;) in a single call to database.run(query)

The bun:sqlite module is roughly 3-6x faster than better-sqlite3 and 8-9x faster than deno.land/x/sqlite for read queries. Each driver was benchmarked against the Northwind Traders dataset. View and run the benchmark source.

Database

To open or create a SQLite3 database:

import { Database } from "bun:sqlite";

const db = new Database("mydb.sqlite");

To open an in-memory database:

import { Database } from "bun:sqlite";

// all of these do the same thing
const db = new Database(":memory:");
const db = new Database();
const db = new Database("");

To open in readonly mode:

import { Database } from "bun:sqlite";
const db = new Database("mydb.sqlite", { readonly: true });

To create the database if the file doesn't exist:

import { Database } from "bun:sqlite";
const db = new Database("mydb.sqlite", { create: true });

Strict mode

By default, bun:sqlite requires binding parameters to include the $, :, or @ prefix, and does not throw an error if a parameter is missing.

To instead throw an error when a parameter is missing and allow binding without a prefix, set strict: true on the Database constructor:

import { Database } from "bun:sqlite";

const strict = new Database(":memory:", { strict: true });

// throws error because of the typo:
const query = strict.query("SELECT $message;").all({ messag: "Hello world" });

const notStrict = new Database(":memory:");
// does not throw error:
notStrict.query("SELECT $message;").all({ messag: "Hello world" });

Load via ES module import

You can also use an import attribute to load a database.

import db from "./mydb.sqlite" with { type: "sqlite" };

console.log(db.query("select * from users LIMIT 1").get());

This is equivalent to the following:

import { Database } from "bun:sqlite";
const db = new Database("./mydb.sqlite");

`.close(throwOnError: boolean = false)`

To close a database connection, but allow existing queries to finish, call .close(false):

const db = new Database();
// ... do stuff
db.close(false);

To close the database and throw an error if there are any pending queries, call .close(true):

const db = new Database();
// ... do stuff
db.close(true);

`using` statement

You can use the using statement to ensure that a database connection is closed when the using block is exited.

import { Database } from "bun:sqlite";

{
  using db = new Database("mydb.sqlite");
  using query = db.query("select 'Hello world' as message;");
  console.log(query.get());
}

{ message: "Hello world" }

`.serialize()`

bun:sqlite supports SQLite's built-in mechanism for serializing and deserializing databases to and from memory.

const olddb = new Database("mydb.sqlite");
const contents = olddb.serialize(); // => Uint8Array
const newdb = Database.deserialize(contents);

Internally, .serialize() calls sqlite3_serialize.

`.query()`

Use the db.query() method on your Database instance to prepare a SQL query. The result is a Statement instance that will be cached on the Database instance. The query will not be executed.

const query = db.query(`select "Hello world" as message`);

The caching refers to the compiled prepared statement (the SQL bytecode), not the query results. When you call db.query() with the same SQL string multiple times, Bun returns the same cached Statement object instead of recompiling the SQL.

It is completely safe to reuse a cached statement with different parameter values:

const query = db.query("SELECT * FROM users WHERE id = ?");
query.get(1); // ✓ Works
query.get(2); // ✓ Also works - parameters are bound fresh each time
query.get(3); // ✓ Still works

Use .prepare() instead of .query() when you want a fresh Statement instance that isn't cached, for example if you're dynamically generating SQL and don't want to fill the cache with one-off queries.

// compile the prepared statement without caching
const query = db.prepare("SELECT * FROM foo WHERE bar = ?");

WAL mode

SQLite supports write-ahead log mode (WAL) which dramatically improves performance, especially in situations with many concurrent readers and a single writer. It's broadly recommended to enable WAL mode for most typical applications.

To enable WAL mode, run this pragma query at the beginning of your application:

db.run("PRAGMA journal_mode = WAL;");

On macOS, WAL files may be persistent by default. This is not a bug, it is how macOS configured the system version of SQLite.

Statements

A Statement is a prepared query, which means it's been parsed and compiled into an efficient binary form. It can be executed multiple times in a performant way.

Create a statement with the .query method on your Database instance.

const query = db.query(`select "Hello world" as message`);

Queries can contain parameters. These can be numerical (?1) or named ($param or :param or @param).

const query = db.query(`SELECT ?1, ?2;`);
const query = db.query(`SELECT $param1, $param2;`);

Values are bound to these parameters when the query is executed. A Statement can be executed with several different methods, each returning the results in a different form.

Binding values

To bind values to a statement, pass an object to the .all(), .get(), .run(), or .values() method.

const query = db.query(`select $message;`);
query.all({ $message: "Hello world" });

You can bind using positional parameters too:

const query = db.query(`select ?1;`);
query.all("Hello world");

`strict: true` lets you bind values without prefixes

By default, the $, :, and @ prefixes are included when binding values to named parameters. To bind without these prefixes, use the strict option in the Database constructor.

import { Database } from "bun:sqlite";

const db = new Database(":memory:", {
  // bind values without prefixes
  strict: true, // [!code ++]
});

const query = db.query(`select $message;`);

// strict: true
query.all({ message: "Hello world" });

// strict: false
// query.all({ $message: "Hello world" });

`.all()`

Use .all() to run a query and get back the results as an array of objects.

const query = db.query(`select $message;`);
query.all({ $message: "Hello world" });

[{ message: "Hello world" }]

Internally, this calls sqlite3_reset and repeatedly calls sqlite3_step until it returns SQLITE_DONE.

`.get()`

Use .get() to run a query and get back the first result as an object.

const query = db.query(`select $message;`);
query.get({ $message: "Hello world" });

{ $message: "Hello world" }

Internally, this calls sqlite3_reset followed by sqlite3_step until it no longer returns SQLITE_ROW. If the query returns no rows, undefined is returned.

`.run()`

Use .run() to run a query and get back an object with execution metadata. This is useful for schema-modifying queries (e.g. CREATE TABLE) or bulk write operations.

const query = db.query(`create table foo;`);
query.run();

{
  lastInsertRowid: 0,
  changes: 0,
}

Internally, this calls sqlite3_reset and calls sqlite3_step once. Stepping through all the rows is not necessary when you don't care about the results.

The lastInsertRowid property returns the ID of the last row inserted into the database. The changes property is the number of rows affected by the query.

`.as(Class)` - Map query results to a class

Use .as(Class) to run a query and get back the results as instances of a class. This lets you attach methods & getters/setters to results.

class Movie {
  title: string;
  year: number;

  get isMarvel() {
    return this.title.includes("Marvel");
  }
}

const query = db.query("SELECT title, year FROM movies").as(Movie);
const movies = query.all();
const first = query.get();

console.log(movies[0].isMarvel);
console.log(first.isMarvel);

true
true

As a performance optimization, the class constructor is not called, default initializers are not run, and private fields are not accessible. This is more like using Object.create than new. The class's prototype is assigned to the object, methods are attached, and getters/setters are set up, but the constructor is not called.

The database columns are set as properties on the class instance.

`.iterate()` (`@@iterator`)

Use .iterate() to run a query and incrementally return results. This is useful for large result sets that you want to process one row at a time without loading all the results into memory.

const query = db.query("SELECT * FROM foo");
for (const row of query.iterate()) {
  console.log(row);
}

You can also use the @@iterator protocol:

const query = db.query("SELECT * FROM foo");
for (const row of query) {
  console.log(row);
}

`.values()`

Use values() to run a query and get back all results as an array of arrays.

const query = db.query(`select $message;`);

query.values({ $message: "Hello world" });
query.values(2);

[
  [ "Iron Man", 2008 ],
  [ "The Avengers", 2012 ],
  [ "Ant-Man: Quantumania", 2023 ],
]

Internally, this calls sqlite3_reset and repeatedly calls sqlite3_step until it returns SQLITE_DONE.

`.finalize()`

Use .finalize() to destroy a Statement and free any resources associated with it. Once finalized, a Statement cannot be executed again. Typically, the garbage collector will do this for you, but explicit finalization may be useful in performance-sensitive applications.

const query = db.query("SELECT title, year FROM movies");
const movies = query.all();
query.finalize();

`.toString()`

Calling toString() on a Statement instance prints the expanded SQL query. This is useful for debugging.

import { Database } from "bun:sqlite";

// setup
const query = db.query("SELECT $param;");

console.log(query.toString()); // => "SELECT NULL"

query.run(42);
console.log(query.toString()); // => "SELECT 42"

query.run(365);
console.log(query.toString()); // => "SELECT 365"

Internally, this calls sqlite3_expanded_sql. The parameters are expanded using the most recently bound values.

Parameters

Queries can contain parameters. These can be numerical (?1) or named ($param or :param or @param). Bind values to these parameters when executing the query:

const query = db.query("SELECT * FROM foo WHERE bar = $bar");
const results = query.all({
  $bar: "bar",
});

[{ "$bar": "bar" }]

Numbered (positional) parameters work too:

const query = db.query("SELECT ?1, ?2");
const results = query.all("hello", "goodbye");

[
	{
		"?1": "hello",
		"?2": "goodbye",
	},
];

Integers

sqlite supports signed 64 bit integers, but JavaScript only supports signed 52 bit integers or arbitrary precision integers with bigint.

bigint input is supported everywhere, but by default bun:sqlite returns integers as number types. If you need to handle integers larger than 2^53, set safeIntegers option to true when creating a Database instance. This also validates that bigint passed to bun:sqlite do not exceed 64 bits.

By default, bun:sqlite returns integers as number types. If you need to handle integers larger than 2^53, you can use the bigint type.

`safeIntegers: true`

When safeIntegers is true, bun:sqlite will return integers as bigint types:

import { Database } from "bun:sqlite";

const db = new Database(":memory:", { safeIntegers: true });
const query = db.query(`SELECT ${BigInt(Number.MAX_SAFE_INTEGER) + 102n} as max_int`);
const result = query.get();

console.log(result.max_int);

9007199254741093n

When safeIntegers is true, bun:sqlite will throw an error if a bigint value in a bound parameter exceeds 64 bits:

import { Database } from "bun:sqlite";

const db = new Database(":memory:", { safeIntegers: true });
db.run("CREATE TABLE test (id INTEGER PRIMARY KEY, value INTEGER)");

const query = db.query("INSERT INTO test (value) VALUES ($value)");

try {
  query.run({ $value: BigInt(Number.MAX_SAFE_INTEGER) ** 2n });
} catch (e) {
  console.log(e.message);
}

BigInt value '81129638414606663681390495662081' is out of range

`safeIntegers: false` (default)

When safeIntegers is false, bun:sqlite will return integers as number types and truncate any bits beyond 53:

import { Database } from "bun:sqlite";

const db = new Database(":memory:", { safeIntegers: false });
const query = db.query(`SELECT ${BigInt(Number.MAX_SAFE_INTEGER) + 102n} as max_int`);
const result = query.get();
console.log(result.max_int);

9007199254741092

Transactions

Transactions are a mechanism for executing multiple queries in an atomic way; that is, either all of the queries succeed or none of them do. Create a transaction with the db.transaction() method:

const insertCat = db.prepare("INSERT INTO cats (name) VALUES ($name)");
const insertCats = db.transaction(cats => {
  for (const cat of cats) insertCat.run(cat);
});

At this stage, we haven't inserted any cats! The call to db.transaction() returns a new function (insertCats) that wraps the function that executes the queries.

To execute the transaction, call this function. All arguments will be passed through to the wrapped function; the return value of the wrapped function will be returned by the transaction function. The wrapped function also has access to the this context as defined where the transaction is executed.

const insert = db.prepare("INSERT INTO cats (name) VALUES ($name)");
const insertCats = db.transaction(cats => {
  for (const cat of cats) insert.run(cat);
  return cats.length;
});

const count = insertCats([{ $name: "Keanu" }, { $name: "Salem" }, { $name: "Crookshanks" }]);

console.log(`Inserted ${count} cats`);

The driver will automatically begin a transaction when insertCats is called and commit it when the wrapped function returns. If an exception is thrown, the transaction will be rolled back. The exception will propagate as usual; it is not caught.

const adopt = db.transaction(cats => {
  insertExpense.run("adoption fees", 20);
  insertCats(cats); // nested transaction
});

adopt([
  { $name: "Joey", $age: 2 },
  { $name: "Sally", $age: 4 },
  { $name: "Junior", $age: 1 },
]);
```

Transactions also come with deferred, immediate, and exclusive versions.

insertCats(cats); // uses "BEGIN"
insertCats.deferred(cats); // uses "BEGIN DEFERRED"
insertCats.immediate(cats); // uses "BEGIN IMMEDIATE"
insertCats.exclusive(cats); // uses "BEGIN EXCLUSIVE"

`.loadExtension()`

To load a SQLite extension, call .loadExtension(name) on your Database instance

import { Database } from "bun:sqlite";

const db = new Database();
db.loadExtension("myext");

brew install sqlite
which sqlite # get path to binary

To point bun:sqlite to the new build, call Database.setCustomSQLite(path) before creating any Database instances. (On other operating systems, this is a no-op.) Pass a path to the SQLite .dylib file, not the executable. With recent versions of Homebrew this is something like /opt/homebrew/Cellar/sqlite/<version>/libsqlite3.dylib.

import { Database } from "bun:sqlite";

Database.setCustomSQLite("/path/to/libsqlite.dylib");

const db = new Database();
db.loadExtension("myext");

`.fileControl(cmd: number, value: any)`

To use the advanced sqlite3_file_control API, call .fileControl(cmd, value) on your Database instance.

import { Database, constants } from "bun:sqlite";

const db = new Database();
// Ensure WAL mode is NOT persistent
// this prevents wal files from lingering after the database is closed
db.fileControl(constants.SQLITE_FCNTL_PERSIST_WAL, 0);

value can be:

number
TypedArray
undefined or null

Reference

class Database {
  constructor(
    filename: string,
    options?:
      | number
      | {
          readonly?: boolean;
          create?: boolean;
          readwrite?: boolean;
          safeIntegers?: boolean;
          strict?: boolean;
        },
  );

  query<ReturnType, ParamsType>(sql: string): Statement<ReturnType, ParamsType>;
  prepare<ReturnType, ParamsType>(sql: string): Statement<ReturnType, ParamsType>;
  run(sql: string, params?: SQLQueryBindings): { lastInsertRowid: number; changes: number };
  exec = this.run;

  transaction(insideTransaction: (...args: any) => void): CallableFunction & {
    deferred: (...args: any) => void;
    immediate: (...args: any) => void;
    exclusive: (...args: any) => void;
  };

  close(throwOnError?: boolean): void;
}

class Statement<ReturnType, ParamsType> {
  all(...params: ParamsType[]): ReturnType[];
  get(...params: ParamsType[]): ReturnType | null;
  run(...params: ParamsType[]): {
    lastInsertRowid: number;
    changes: number;
  };
  values(...params: ParamsType[]): unknown[][];

  finalize(): void; // destroy statement and clean up resources
  toString(): string; // serialize to SQL

  columnNames: string[]; // the column names of the result set
  columnTypes: string[]; // types based on actual values in first row (call .get()/.all() first)
  declaredTypes: (string | null)[]; // types from CREATE TABLE schema (call .get()/.all() first)
  paramsCount: number; // the number of parameters expected by the statement
  native: any; // the native object representing the statement

  as<T>(Class: new (...args: any[]) => T): Statement<T, ParamsType>;
}

type SQLQueryBindings =
  | string
  | bigint
  | TypedArray
  | number
  | boolean
  | null
  | Record<string, string | bigint | TypedArray | number | boolean | null>;

Datatypes

JavaScript type	SQLite type
`string`	`TEXT`
`number`	`INTEGER` or `DECIMAL`
`boolean`	`INTEGER` (1 or 0)
`Uint8Array`	`BLOB`
`Buffer`	`BLOB`
`bigint`	`INTEGER`
`null`	`NULL`

Bun SQLite

File contents

SQLite

Database

Strict mode

Load via ES module import

`.close(throwOnError: boolean = false)`

`using` statement

`.serialize()`

`.query()`

WAL mode

Statements

Binding values

`strict: true` lets you bind values without prefixes

`.all()`

`.get()`

`.run()`

`.as(Class)` - Map query results to a class

`.iterate()` (`@@iterator`)

`.values()`

`.finalize()`

`.toString()`

Parameters

Integers

`safeIntegers: true`

`safeIntegers: false` (default)

Transactions

`.loadExtension()`

`.fileControl(cmd: number, value: any)`

Reference

Datatypes

Frequently asked questions

Bun SQLite

File contents

SQLite

Database

Strict mode

Load via ES module import

.close(throwOnError: boolean = false)

using statement

.serialize()

.query()

WAL mode

Statements

Binding values

strict: true lets you bind values without prefixes

.all()

.get()

.run()

.as(Class) - Map query results to a class

.iterate() (@@iterator)

.values()

.finalize()

.toString()

Parameters

Integers

safeIntegers: true

safeIntegers: false (default)

Transactions

.loadExtension()

.fileControl(cmd: number, value: any)

Reference

Datatypes

Related skills

Frequently asked questions

How do I install the Bun SQLite skill?

What does the Bun SQLite skill do?

Is Bun SQLite safe to use?

Which AI agents work with Bun SQLite?

Is Bun SQLite free to use?

Who published Bun SQLite?

`.close(throwOnError: boolean = false)`

`using` statement

`.serialize()`

`.query()`

`strict: true` lets you bind values without prefixes

`.all()`

`.get()`

`.run()`

`.as(Class)` - Map query results to a class

`.iterate()` (`@@iterator`)

`.values()`

`.finalize()`

`.toString()`

`safeIntegers: true`

`safeIntegers: false` (default)

`.loadExtension()`

`.fileControl(cmd: number, value: any)`