Getting Started

Simple guide to get a moor project up and running

Note: If you prefer a tutorial video, Reso Coder has made a detailed video explaining how to get started. You can watch it here.

Adding the dependency

First, lets add moor to your project’s pubspec.yaml. At the moment, the current version of moor_flutter is Flutter version and the current version of moor_generator is Generator version

  moor_flutter: # use the latest version

  moor_generator: # use the latest version

We’re going to use the moor_flutter library to specify tables and access the database. The moor_generator library will take care of generating the necessary code so the library knows what your table structure looks like.

Declaring tables

Using moor, you can model the structure of your tables with simple dart code:

import 'package:moor_flutter/moor_flutter.dart';

// assuming that your file is called filename.dart. This will give an error at first,
// but it's needed for moor to know about the generated code
part 'filename.g.dart'; 

// this will generate a table called "todos" for us. The rows of that table will
// be represented by a class called "Todo".
class Todos extends Table {
  IntColumn get id => integer().autoIncrement()();
  TextColumn get title => text().withLength(min: 6, max: 32)();
  TextColumn get content => text().named('body')();
  IntColumn get category => integer().nullable()();

// This will make moor generate a class called "Category" to represent a row in this table.
// By default, "Categorie" would have been used because it only strips away the trailing "s"
// in the table name.
class Categories extends Table {
  IntColumn get id => integer().autoIncrement()();
  TextColumn get description => text()();

// this annotation tells moor to prepare a database class that uses both of the
// tables we just defined. We'll see how to use that database class in a moment.
@UseMoor(tables: [Todos, Categories])
class MyDatabase {

⚠️ Note: The column definitions, the table name and the primary key must be known at compile time. For column definitions and the primary key, the function must use the => operator and can’t contain anything more than what’s included in the documentation and the examples. Otherwise, the generator won’t be able to know what’s going on.

Generating the code

Moor integrates with Dart’s build system, so you can generate all the code needed with flutter packages pub run build_runner build. If you want to continuously rebuild the generated code whever you change your code, run flutter packages pub run build_runner watch instead. After running either command once, the moor generator will have created a class for your database and data classes for your entities. To use it, change the MyDatabase class as follows:

@UseMoor(tables: [Todos, Categories])
class MyDatabase extends _$MyDatabase {
  // we tell the database where to store the data with this constructor
  MyDatabase() : super(FlutterQueryExecutor.inDatabaseFolder(path: 'db.sqlite'));

  // you should bump this number whenever you change or add a table definition. Migrations
  // are covered later in this readme.
  int get schemaVersion => 1; 

Getting started with sql

Learn how to get started with the SQL version of moor, or how to migrate an existing project to moor.

Writing queries

Learn how to write database queries in pure Dart with moor


Deep-dive into what kind of SQL expressions can be written in Dart

Last modified October 1, 2019: More guides for moor 2.0 (742cec4d)