Dart Client

The latest stable version of the DuckDB Dart client is 1.4.4.

DuckDB.Dart is the native Dart API for DuckDB.

Installation

DuckDB.Dart can be installed from pub.dev. Please see the API Reference for details.

Use This Package as a Library

Depend on It

Add the dependency with Flutter:

flutter pub add dart_duckdb

This will add a line like this to your package’s pubspec.yaml (and run an implicit flutter pub get):

dependencies:
  dart_duckdb: ^

Alternatively, your editor might support flutter pub get. Check the docs for your editor to learn more.

Import It

Now in your Dart code, you can import it:

import 'package:dart_duckdb/dart_duckdb.dart';

Usage Examples

See the example projects in the duckdb-dart repository:

cli: command-line application
duckdbexplorer: GUI application which builds for desktop operating systems as well as Android and iOS.

Here are some common code snippets for DuckDB.Dart:

Querying an In-Memory Database

import 'package:dart_duckdb/dart_duckdb.dart';

void main() async {
  final db = await duckdb.open(":memory:");
  final connection = await duckdb.connect(db);

  await connection.execute('''
    CREATE TABLE users (id INTEGER, name VARCHAR, age INTEGER);
    INSERT INTO users VALUES (1, 'Alice', 30), (2, 'Bob', 25);
  ''');

  final result = (await connection.query("SELECT * FROM users WHERE age > 28")).fetchAll();

  for (final row in result) {
    print(row);
  }

  connection.dispose();
  db.dispose();
}

Using Multiple Connections

DuckDB.Dart automatically manages dedicated background isolates per connection, enabling efficient non-blocking I/O for concurrent queries. Each connection handles its own isolate internally, so you can simply create multiple connections for parallel operations:

import 'package:dart_duckdb/dart_duckdb.dart';

void main() async {
  final db = await duckdb.open(":memory:");

  // Create a table
  final con1 = await duckdb.connect(db);
  await con1.execute('''
    CREATE TABLE users (id INTEGER, name VARCHAR);
    INSERT INTO users VALUES (1, 'Alice'), (2, 'Bob');
  ''');

  // Query from multiple connections concurrently
  final con2 = await duckdb.connect(db);
  final con3 = await duckdb.connect(db);

  final future1 = con2.query("SELECT * FROM users WHERE id = 1");
  final future2 = con3.query("SELECT * FROM users WHERE id = 2");

  final result1 = (await future1).fetchAll();
  final result2 = (await future2).fetchAll();

  print(result1);
  print(result2);

  con1.dispose();
  con2.dispose();
  con3.dispose();
  db.dispose();
}

Web Support

DuckDB.Dart supports web platforms through DuckDB WASM. For Flutter web builds, you need to configure the necessary JavaScript dependencies.

Setup for Flutter Web

Add the following to web/index.html inside the <head> section to load DuckDB WASM and Apache Arrow:

<script type="importmap">
  {
    "imports": {
      "apache-arrow": "https://cdn.jsdelivr.net/npm/[email protected]/+esm"
    }
  }
</script>
<script type="module">
  import * as duckdb from "https://cdn.jsdelivr.net/npm/@duckdb/[email protected]/+esm";
  import * as arrow from "apache-arrow";
  window.duckdbWasmReady = new Promise((resolve) => {
    window.duckdbduckdbWasm = duckdb;
    window.ArrowTable = arrow.Table;
    resolve();
  });
</script>

Usage in Flutter Web

Once configured, you can use DuckDB the same way as on other platforms:

import 'package:dart_duckdb/dart_duckdb.dart';

void main() async {
  final db = await duckdb.open(":memory:");
  final connection = await duckdb.connect(db);

  await connection.execute('''
    CREATE TABLE data (id INTEGER, value VARCHAR);
    INSERT INTO data VALUES (1, 'hello'), (2, 'world');
  ''');

  final result = (await connection.query("SELECT * FROM data")).fetchAll();
  for (final row in result) {
    print(row);
  }

  connection.dispose();
  db.dispose();
}

For more platform-specific details, see the Building Instructions.