bun-types
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Type definitions and documentation for Bun, an incredibly fast JavaScript runtime
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Markdown
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`)
- 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](https://github.com/jpwhite3/northwind-SQLite3/blob/46d5f8a64f396f87cd374d1600dbf521523980e8/Northwind_large.sqlite.zip) dataset. View and run the [benchmark source](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 });
```
### Strict mode
{% callout %}
Added in Bun v1.1.14
{% /callout %}
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:
<!-- prettier-ignore -->
```ts
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({ message: "Hello world" });
const notStrict = new Database(
":memory:"
);
// does not throw error:
notStrict
.query("SELECT $message;")
.all({ message: "Hello world" });
```
### Load via ES module import
You can also use an import attribute to load a database.
```ts
import db from "./mydb.sqlite" with { "type": "sqlite" };
console.log(db.query("select * from users LIMIT 1").get());
```
This is equivalent to the following:
```ts
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)`:
```ts
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)`:
```ts
const db = new Database();
// ... do stuff
db.close(true);
```
Note: `close(false)` is called automatically when the database is garbage collected. It is safe to call multiple times but has no effect after the first.
### `using` statement
You can use the `using` statement to ensure that a database connection is closed when the `using` block is exited.
```ts
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](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 = olddb.serialize(); // => Uint8Array
const newdb = Database.deserialize(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 %}
## WAL mode
SQLite supports [write-ahead log mode](https://www.sqlite.org/wal.html) (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:
```ts
db.exec("PRAGMA journal_mode = WAL;");
```
{% details summary="What is WAL mode" %}
In WAL mode, writes to the database are written directly to a separate file called the "WAL file" (write-ahead log). This file will be later integrated into the main database file. Think of it as a buffer for pending writes. Refer to the [SQLite docs](https://www.sqlite.org/wal.html) for a more detailed overview.
On macOS, WAL files may be persistent by default. This is not a bug, it is how macOS configured the system version of SQLite.
{% /details %}
## 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.
### Binding values
To bind values to a statement, pass an object to the `.all()`, `.get()`, `.run()`, or `.values()` method.
```ts
const query = db.query(`select $message;`);
query.all({ $message: "Hello world" });
```
You can bind using positional parameters too:
```ts
const query = db.query(`select ?1;`);
query.all("Hello world");
```
#### `strict: true` lets you bind values without prefixes
{% callout %}
Added in Bun v1.1.14
{% /callout %}
By default, the `$`, `:`, and `@` prefixes are **included** when binding values to named parameters. To bind without these prefixes, use the `strict` option in the `Database` constructor.
```ts
import { Database } from "bun:sqlite";
const db = new Database(":memory:", {
// bind values without prefixes
strict: true,
});
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.
```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 schema-modifying queries (e.g. `CREATE TABLE`) or bulk write operations.
```ts
const query = db.query(`create table foo;`);
query.run();
// {
// lastInsertRowid: 0,
// changes: 0,
// }
```
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.
{% callout %}
Since Bun v1.1.14, `.run()` returns an object with two properties: `lastInsertRowid` and `changes`.
{% /callout %}
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
{% callout %}
Added in Bun v1.1.14
{% /callout %}
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.
```ts
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); // => true
console.log(first.isMarvel); // => 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.
```ts
const query = db.query("SELECT * FROM foo");
for (const row of query.iterate()) {
console.log(row);
}
```
You can also use the `@@iterator` protocol:
```ts
const query = db.query("SELECT * FROM foo");
for (const row of query) {
console.log(row);
}
```
This feature was added in Bun v1.1.31.
### `.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 %}
## 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`
{% callout %}
Added in Bun v1.1.14
{% /callout %}
When `safeIntegers` is `true`, `bun:sqlite` will return integers as `bigint` types:
```ts
import { Database } from "bun:sqlite";
const db = new Database(":memory:", { safeIntegers: true });
const query = db.query(
`SELECT ${BigInt(Number.MAX_SAFE_INTEGER) + 102n} as max_int`,
);
const result = query.get();
console.log(result.max_int); // => 9007199254741093n
```
When `safeIntegers` is `true`, `bun:sqlite` will throw an error if a `bigint` value in a bound parameter exceeds 64 bits:
```ts
import { Database } from "bun:sqlite";
const db = new Database(":memory:", { safeIntegers: true });
db.run("CREATE TABLE test (id INTEGER PRIMARY KEY, value INTEGER)");
const query = db.query("INSERT INTO test (value) VALUES ($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:
```ts
import { Database } from "bun:sqlite";
const db = new Database(":memory:", { safeIntegers: false });
const query = db.query(
`SELECT ${BigInt(Number.MAX_SAFE_INTEGER) + 102n} as max_int`,
);
const result = query.get();
console.log(result.max_int); // => 9007199254741092
```
## Transactions
Transactions are a mechanism for executing multiple queries in an _atomic_ way; that is, either all of the queries succeed or none of them do. Create a transaction with the `db.transaction()` method:
```ts
const insertCat = db.prepare("INSERT INTO cats (name) VALUES ($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 %}
### .fileControl(cmd: number, value: any)
To use the advanced `sqlite3_file_control` API, call `.fileControl(cmd, value)` on your `Database` instance.
```ts
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
```ts
class Database {
constructor(
filename: string,
options?:
| number
| {
readonly?: boolean;
create?: boolean;
readwrite?: boolean;
},
);
query<Params, ReturnType>(sql: string): Statement<Params, ReturnType>;
run(
sql: string,
params?: SQLQueryBindings,
): { lastInsertRowid: number; changes: number };
exec = this.run;
}
class Statement<Params, ReturnType> {
all(params: Params): ReturnType[];
get(params: Params): ReturnType | undefined;
run(params: Params): {
lastInsertRowid: number;
changes: number;
};
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
as(Class: new () => ReturnType): this;
}
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` |