moor 2.0.1

  • Readme
  • Changelog
  • Example
  • Installing
  • 93

moor #

Moor is an easy to use, reactive persistence library for Flutter apps. Define your database tables in pure Dart and enjoy a fluent query API, auto-updating streams and more!

With Flutter #

This library defines the APIs for the moor persistence library. To use it on Flutter apps, you'll probably want to use the moor_flutter implementation directly.

For the web #

For information to use this library on the web (including Flutter web), follow the instructions here. Keep in mind that web support is still experimental.

Please see the homepage of moor or the moor_flutter package for details on how to use this package.

2.0.1 #

  • Introduced isBetween and isBetweenValues methods for comparable expressions (int, double, datetime) to check values for both an upper and lower bound
  • Automatically map BOOLEAN and DATETIME columns declared in a sql file to the appropriate type (both used to be double before).
  • Fix streams not emitting cached data when listening multiple times
  • Breaking: Remove the type parameter from Insertable.createCompanion (it was declared as an internal method)

2.0.0 #

This is the first major update after the initial release and moor and we have a lot to cover: .moor files can now have their own imports and queries, you can embed Dart in sql queries using the new templates feature and we have a prototype of a pure-Dart SQL IDE ready. Finally, we also removed a variety of deprecated features. See the breaking changes section to learn what components are affected and what alternatives are available.

New features #

Updates to the sql parser #

.moor files were introduced in moor 1.7 as an experimental way to declare tables by using CREATE TABLE statements. In this version, they become stable and support their own import and query system. This allows you to write queries in their own file:


findByName: SELECT * FROM users WHERE name LIKE :query;

When this file is included from a @UseMoor annotation, moor will generate methods to run the query. Of course, you can also write Dart queries for tables declared in sql:

Stream<User> loadUserById(int id) {
 return (select(users)..where((u) =>;

Moor files can also import other moor files by using an import 'other.moor'; statement at the top. Then, all tables defined in other.moor will also be available to the current file.

Moor takes Dart and SQL interop even further with the new "Dart in SQL templates". You can define a query like this:

findDynamic: SELECT * FROM users WHERE $condition;

And moor will generate a method findDynamic(Expression<bool, BoolType> condition) for you. This allows you to bind the template with a predicate as complex as you'd like. At the moment, Dart templates are supported for expressions, OrderBy, OrderingTerm and Limit.

INSERT statements can now be used as a compiled statement - both in moor files and in a @UseMoor or @UseDao annotation. A new builtin linter will even warn you when you forget to provide a value for a non-nullable column - right at compile time!

And finally, we now generate better query code when queries only return a single column. Instead of generating a whole new class for that, we simply return the value directly.

Experimental ffi support #

We released an experimental version of moor built on top of dart:ffi. It works cross-platform and is much, much faster than moor_flutter. It you want to try it out, read the docs here.

Minor changes #

  • a Constant<String> can now be written to SQL, it used to throw before. This is useful if you need default values for strings columns. This also works for BLOBS (Constant<Uint8List>).
  • new LazyDatabase for when you want to construct a database asynchronously (for instance, if you first need to find a file before you can open a database).

Breaking changes #

  • THIS LIKELY AFFECTS YOUR APP: Removed the transaction parameter for callbacks in transactions and beforeOpen callbacks. So, instead of writing

    transaction((t) async {
      await t.update(table)...;

    simply write

    transaction(() async {
      await update(table)...;

    Similarly, instead of using onOpen: (db, details) async {...}, use onOpen: (details) async {...}. You don't have to worry about calling methods on your database instead of a transaction objects. They will be delegated automatically.

    On a similar note, we also removed the operateOn parameter from compiled queries.

  • Compiled queries that return only a single column (e.g. SELECT COUNT(*) FROM users) will just return their value (in this case, an int) now. Moor no longer generates a new class in that case.

  • Removed MigrationStrategy.onFinished. Use beforeOpen instead.

  • Compiled sql queries starting with an underscore will now generate private match queries. Previously, the query _allUsers would generate a watchAllUsers method, that has been adopted to _watchAllUsers. The generate_private_watch_methods builder option, which backported this fix to older versions, has thus been removed.

  • Removed InsertStatement.insertOrReplace. Use insert(data, orReplace: true) instead.

  • Removed the diff util and MoorAnimatedList. Use a third party library for that.

1.7.2 #

  • Fixed a race condition that caused the database to be opened multiple times on slower devices. This problem was introduced in 1.7.0 and was causing problems during migrations.

1.7.1 #

  • Better documentation on getSingle and watchSingle for queries.
  • Fix INTEGER NOT NULL PRIMARY KEY wrongly requiring a value during insert (this never affected AUTOINCREMENT columns, and only affects columns declared in a .moor file)

1.7.0 #

  • Support custom columns via type converters. See the docs for details on how to use this feature.
  • Transactions now roll back when not completed successfully, they also rethrow the exception to make debugging easier.
  • New backends api, making it easier to write database drivers that work with moor. Apart from moor_flutter, new experimental backends can be checked out from git:
    1. encrypted_moor: An encrypted moor database:
    2. moor_mysql: Work in progress mysql backend for moor.
  • The compiled sql feature is no longer experimental and will stay stable until a major version bump
  • New, experimental support for .moor files! Instead of declaring your tables in Dart, you can choose to declare them with sql by writing the CREATE TABLE statement in a .moor file. You can then use these tables in the database and with daos by using the include parameter on @UseMoor and @UseDao. Again, please notice that this is an experimental api and there might be some hiccups. Please report any issues you run into.

1.6.0 #

  • Experimental web support! See the documentation for details.
  • Make transactions easier to use: Thanks to some Dart async magic, you no longer need to run queries on the transaction explicitly. This
    Future deleteCategory(Category category) {
      return transaction((t) async {
        await t.delete(categories).delete(category);
    is now the same as this (notice how we don't have to use the t. in front of the delete)
      Future deleteCategory(Category category) {
        return transaction((t) async {
          await delete(categories).delete(category);
    This makes it much easier to compose operations by extracting them into methods, as you don't have to worry about not using the t parameter.
  • Moor now provides syntax sugar for list parameters in compiled custom queries (SELECT * FROM entries WHERE id IN ?)
  • Support COLLATE expressions.
  • Date time columns are now comparable
  • The StringType now supports arbitrary data from sqlite (#70). Thanks, knaeckeKami!
  • Bugfixes related to stream queries and LIMIT clauses.

1.5.1 #

  • Fixed an issue where transformed streams would not always update
  • Emit a INSERT INTO table DEFAULT VALUES when appropriate. Moor used to generate invalid sql before.

1.5.0 #

This version introduces some new concepts and features, which are explained in more detail below. Here is a quick overview of the new features:

  • More consistent and reliable callbacks for migrations. You can now use MigrationStrategy.beforeOpen to run queries after migrations, but before fully opening the database. This is useful to initialize data.
  • Greatly expanded documentation, introduced additional checks to provide more helpful error messages
  • New getSingle and watchSingle methods on queries: Queries that you know will only return one row can now be instructed to return the value directly instead of wrapping it in a list.
  • New "update companion" classes to clearly separate between absent values and explicitly setting values back to null - explained below.
  • Experimental support for compiled sql queries: Moor can now generate typesafe APIs for written sql. Read on to get started.

Update companions #

Newly introduced "Update companions" allow you to insert or update data more precisely than before. Previously, there was no clear separation between "null" and absent values. For instance, let's say we had a table "users" that stores an id, a name, and an age. Now, let's say we wanted to set the age of a user to null without changing its name. Would we use User(age: null)? Here, the name column would implicitly be set to null, so we can't cleanly separate that. However, with UsersCompanion(age: Value(null)), we know the difference between Value(null) and the default Value.absent().

Don't worry, all your existing code will continue to work, this change is fully backwards compatible. You might get analyzer warnings about missing required fields. The migration to update companions will fix that. Replacing normal classes with their update companions is simple and the only thing needed to fix that. The documentation has been updated to reflect this. If you have additional questions, feel free to create an issue.

Compiled sql queries #

Experimental support for compile time custom statements. Sounds super boring, but it actually gives you a fluent way to write queries in pure sql. The moor generator will figure out what your queries return and automatically generate the boring mapping part. Head on to the documentation to find out how to use this new feature.

Please note that this feature is in an experimental state: Expect minor, but breaking changes in the API and in the generated code. Also, if you run into any issues with this feature, reporting them would be super appreciated.

1.4.0 #

  • Added the RealColumn, which stores floating point values
  • Better configuration for the serializer with the JsonKey annotation and the ability to use a custom ValueSerializer

1.3.0 #

  • Moor now supports table joins
    • Added table aliases
  • Default values for columns: Just use the withDefault method when declaring a column
    • added expressions that resolve to the current date or time
  • Fixed a crash that would occur if the first operation was a transaction
  • Better support for custom expressions as part of a regular query
  • Faster hashcode implementation in generated data classes

1.2.0 #

  • Breaking: Generated DAO classes are now called _$YourNameHere, it used to be just _YourNameHere (without the dollar sign)
  • Blob data type
  • insertOrReplace method for insert statements
  • DAOs can now operate on transactions
  • Custom constraints
  • Query streams are now cached so that equal queries yield identical streams. This can improve performance.

1.1.0 #

  • Transactions

1.0.0 #

  • Initial version of the Moor library


import 'package:moor/moor.dart';

part 'example.g.dart';

// Define tables that can model a database of recipes.

class Categories extends Table {
  IntColumn get id => integer().autoIncrement()();
  TextColumn get description => text().nullable()();

class Recipes extends Table {
  IntColumn get id => integer().autoIncrement()();
  TextColumn get title => text().withLength(max: 16)();
  TextColumn get instructions => text()();
  IntColumn get category => integer().nullable()();

class Ingredients extends Table {
  IntColumn get id => integer().autoIncrement()();
  TextColumn get name => text()();
  IntColumn get caloriesPer100g => integer().named('calories')();

class IngredientInRecipes extends Table {
  String get tableName => 'recipe_ingredients';

  // We can also specify custom primary keys
  Set<Column> get primaryKey => {recipe, ingredient};

  IntColumn get recipe => integer()();
  IntColumn get ingredient => integer()();

  IntColumn get amountInGrams => integer().named('amount')();

  tables: [Categories, Recipes, Ingredients, IngredientInRecipes],
  queries: {
    // query to load the total weight for each recipe by loading all ingredients
    // and taking the sum of their amountInGrams.
    '_totalWeight': '''
      SELECT r.title, SUM(ir.amount) AS total_weight
        FROM recipes r
        INNER JOIN recipe_ingredients ir ON ir.recipe =
      GROUP BY
class Database extends _$Database {
  Database(QueryExecutor e) : super(e);

  int get schemaVersion => 1;

  MigrationStrategy get migration {
    return MigrationStrategy(
      beforeOpen: (details) async {
        // populate data
        await into(categories)
            .insert(const CategoriesCompanion(description: Value('Sweets')));

Use this package as a library

1. Depend on it

Add this to your package's pubspec.yaml file:

  moor: ^2.0.1

2. Install it

You can install packages from the command line:

with pub:

$ pub get

with Flutter:

$ flutter pub get

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

3. Import it

Now in your Dart code, you can use:

import 'package:moor/moor.dart';
Describes how popular the package is relative to other packages. [more]
Code health derived from static analysis. [more]
Reflects how tidy and up-to-date the package is. [more]
Weighted score of the above. [more]
Learn more about scoring.

We analyzed this package on Oct 16, 2019, and provided a score, details, and suggestions below. Analysis was completed with status completed using:

  • Dart: 2.5.1
  • pana: 0.12.21


Detected platforms: Flutter, web, other

No platform restriction found in primary library package:moor/moor.dart.


Package Constraint Resolved Available
Direct dependencies
Dart SDK >=2.3.0 <3.0.0
collection ^1.0.0 1.14.12
convert ^2.1.1 2.1.1
meta ^1.0.0 1.1.7
pedantic ^1.0.0 1.8.0+1
synchronized ^2.1.0 2.1.0+1
Transitive dependencies
charcode 1.1.2
typed_data 1.1.6
Dev dependencies
build_runner >=1.3.0 <2.0.0
build_test ^0.10.8
coverage any
grinder ^0.8.3
mockito ^4.1.0
moor_generator ^2.0.0
test ^1.6.4
test_coverage ^0.3.0