Bun natively implements a high-performance [SQLite3](https://www.sqlite.org/) driver. To use it import from the built-in `bun:sqlite` module.

```ts
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](https://github.com/JoshuaWise/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`)
- The fastest performance of any SQLite driver for JavaScript

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](https://github.com/jpwhite3/northwind-SQLite3/blob/46d5f8a64f396f87cd374d1600dbf521523980e8/Northwind_large.sqlite.zip) dataset. View and run the [benchmark source](<[./bench/sqlite](https://github.com/oven-sh/bun/tree/main/bench/sqlite)>).

{% image width="738" alt="SQLite benchmarks for Bun, better-sqlite3, and deno.land/x/sqlite" src="https://user-images.githubusercontent.com/709451/168459263-8cd51ca3-a924-41e9-908d-cf3478a3b7f3.png" caption="Benchmarked on an M1 MacBook Pro (64GB) running macOS 12.3.1" /%}

## Database

To open or create a SQLite3 database:

```ts
import { Database } from "bun:sqlite";

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

To open an in-memory database:

```ts
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:

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

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

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

### `.close()`

To close a database:

```ts
const db = new Database();
db.close();
```

Note: `close()` is called automatically when the database is garbage collected. It is safe to call multiple times but has no effect after the first.

### `.serialize()`

`bun:sqlite` supports SQLite's built-in mechanism for [serializing](https://www.sqlite.org/c3ref/serialize.html) and [deserializing](https://www.sqlite.org/c3ref/deserialize.html) databases to and from memory.

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

Internally, `.serialize()` calls [`sqlite3_serialize`](https://www.sqlite.org/c3ref/serialize.html).

### `.query()`

Use the `db.query()` method on your `Database` instance to [prepare](https://www.sqlite.org/c3ref/prepare.html) a SQL query. The result is a `Statement` instance that will be cached on the `Database` instance. _The query will not be executed._

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

{% callout %}

**Note** — Use the `.prepare()` method to prepare a query _without_ caching it on the `Database` instance.

```ts
// compile the prepared statement
const query = db.prepare("SELECT * FROM foo WHERE bar = ?");
```

{% /callout %}

## 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.

```ts
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`).

```ts
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.

### `.all()`

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

```ts
const query = db.query(`select $message;`);
query.all({ $message: "Hello world" });
// => [{ message: "Hello world" }]
```

Internally, this calls [`sqlite3_reset`](https://www.sqlite.org/capi3ref.html#sqlite3_reset) and repeatedly calls [`sqlite3_step`](https://www.sqlite.org/capi3ref.html#sqlite3_step) until it returns `SQLITE_DONE`.

### `.get()`

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

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

Internally, this calls [`sqlite3_reset`](https://www.sqlite.org/capi3ref.html#sqlite3_reset) followed by [`sqlite3_step`](https://www.sqlite.org/capi3ref.html#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 `undefined`. This is useful for queries schema-modifying queries (e.g. `CREATE TABLE`) or bulk write operations.

```ts
const query = db.query(`create table foo;`);
query.run();
// => undefined
```

Internally, this calls [`sqlite3_reset`](https://www.sqlite.org/capi3ref.html#sqlite3_reset) and calls [`sqlite3_step`](https://www.sqlite.org/capi3ref.html#sqlite3_step) once. Stepping through all the rows is not necessary when you don't care about the results.

### `.values()`

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

```ts
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`](https://www.sqlite.org/capi3ref.html#sqlite3_reset) and repeatedly calls [`sqlite3_step`](https://www.sqlite.org/capi3ref.html#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.

```ts
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.

```ts
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`](https://www.sqlite.org/capi3ref.html#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:

{% codetabs %}

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

```json#Results
[
  { "$bar": "bar" }
]
```

{% /codetabs %}

Numbered (positional) parameters work too:

{% codetabs %}

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

```ts#Results
[
  {
    "?1": "hello",
    "?2": "goodbye"
  }
]
```

{% /codetabs %}

## 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:

```ts
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.

```ts
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`](https://www.sqlite.org/lang_transaction.html) 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.

{% callout %}
**Nested transactions** — Transaction functions can be called from inside other transaction functions. When doing so, the inner transaction becomes a [savepoint](https://www.sqlite.org/lang_savepoint.html).

{% details summary="View nested transaction example" %}

```ts
// setup
import { Database } from "bun:sqlite";
const db = Database.open(":memory:");
db.run(
  "CREATE TABLE expenses (id INTEGER PRIMARY KEY AUTOINCREMENT, note TEXT, dollars INTEGER);",
);
db.run(
  "CREATE TABLE cats (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT UNIQUE, age INTEGER)",
);
const insertExpense = db.prepare(
  "INSERT INTO expenses (note, dollars) VALUES (?, ?)",
);
const insert = db.prepare("INSERT INTO cats (name, age) VALUES ($name, $age)");
const insertCats = db.transaction((cats) => {
  for (const cat of cats) insert.run(cat);
});

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 },
]);
```

{% /details %}
{% /callout %}

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

```ts
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](https://www.sqlite.org/loadext.html), call `.loadExtension(name)` on your `Database` instance

```ts
import { Database } from "bun:sqlite";

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

{% details summary="For macOS users" %}
**MacOS users** By default, macOS ships with Apple's proprietary build of SQLite, which doesn't support extensions. To use extensions, you'll need to install a vanilla build of SQLite.

```bash
$ 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`.

```ts
import { Database } from "bun:sqlite";

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

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

{% /details %}

## Reference

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

  query<Params, ReturnType>(sql: string): Statement<Params, ReturnType>;
}

class Statement<Params, ReturnType> {
  all(params: Params): ReturnType[];
  get(params: Params): ReturnType | undefined;
  run(params: Params): void;
  values(params: Params): unknown[][];

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

  columnNames: string[]; // the column names of the result set
  paramsCount: number; // the number of parameters expected by the statement
  native: any; // the native object representing the statement
}

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`                 |