Source-generated ORM with relations (one-to-one, one-to-many, many-to-many), preloading, cascading, polymorphic relations, etc

Features

• Relationships
  • One To One
  • One To Many
  • Many To Many
• Preloads
• Cascading
  • Cascaded inserts
  • Cascaded updates
  • Cascaded removals
• Migration
• Polymorphic relations
• Composite primary keys
• Composite foreign keys

Getting started

Declaring the Model

class User {
  @PrimaryKey()
  String id;

  String name;

  static const String tableName = '_user';

  String toString() => "User($id, $name)";
}

Declaring the Bean

A Bean performs database actions on behalf of the model. In this case, UserBean performs actions for User model. Much of the Bean's functionality will be source generated.

@GenBean()
class UserBean extends Bean<User> with _UserBean {
  UserBean(Adapter adapter) : super(adapter);
}

Generating Bean logic

jaguar_orm use source_gen and jaguar_orm_gen to generate bean logic from bean specification.

Add the following dependencies to dev_dependencies.

  build_runner:
  jaguar_orm_gen:

Run the following command to generate Bean logic:

pub run build_runner build

Connecting to database

We will use PostgreSQL for this tutorial. PgAdapter is found in the package jaguar_query_postgres.

final PgAdapter _adapter =
    new PgAdapter('example', username: 'postgres', password: 'dart_jaguar');
await _adapter.connect();

Creating instance of bean

Beans internally use jaguar_query's Adapter interface to talk to database. Lets create an instance of UserBean.

final userBean = new UserBean(_adapter);

Dropping the table

await userBean.drop();

Creating a table

await userBean.createTable();

Inserting a new record

await userBean.insert(new User()
    ..id = '1'
    ..name = 'teja');

Fetching record by primary key

User user = await userBean.find('1');

Fetching all records

List<User> users = await userBean.getAll();

Updating a record

User user = await userBean.find('1');
user.name = 'teja hackborn';
await userBean.update(user);

Remove by id

await userBean.remove('1');

Remove all

await userBean.removeAll();

Examples

One-To-One example

class User {
  @PrimaryKey()
  String id;

  String name;

  @HasOne(AddressBean)
  Address address;

  static const String tableName = '_user';

  String toString() => "User($id, $name, $address)";
}

class Address {
  @PrimaryKey()
  String id;

  @BelongsTo(UserBean)
  String userId;

  String street;

  static String tableName = 'address';

  String toString() => "Post($id, $userId, $street)";
}

@GenBean()
class UserBean extends Bean<User> with _UserBean {
  UserBean(Adapter adapter)
      : addressBean = new AddressBean(adapter),
        super(adapter);

  final AddressBean addressBean;

  Future createTable() {
    final st = Sql
        .create(tableName)
        .addStr('id', primary: true, length: 50)
        .addStr('name', length: 50);
    return execCreateTable(st);
  }
}

@GenBean()
class AddressBean extends Bean<Address> with _AddressBean {
  AddressBean(Adapter adapter) : super(adapter);

  Future createTable() {
    final st = Sql
        .create(tableName)
        .addStr('id', primary: true, length: 50)
        .addStr('street', length: 150)
        .addStr('user_id', length: 50, foreignTable: '_user', foreignCol: 'id');
    return execCreateTable(st);
  }
}

/// The adapter
PgAdapter _adapter =
    new PgAdapter('postgres://postgres:[email protected]/example');

main() async {
  // Connect to database
  await _adapter.connect();

  // Create beans
  final userBean = new UserBean(_adapter);
  final addressBean = new AddressBean(_adapter);

  // Drop old tables
  await addressBean.drop();
  await userBean.drop();

  // Create new tables
  await userBean.createTable();
  await addressBean.createTable();

  // Cascaded One-To-One insert
  {
    final user = new User()
      ..id = '1'
      ..name = 'Teja'
      ..address = (new Address()
        ..id = '1'
        ..street = 'Stockholm');
    await userBean.insert(user, cascade: true);
  }

  // Fetch One-To-One preloaded
  {
    final user = await userBean.find('1', preload: true);
    print(user);
  }

  // Manual One-To-One insert
  {
    User user = new User()
      ..id = '2'
      ..name = 'Kleak';
    await userBean.insert(user, cascade: true);

    user = await userBean.find('2');

    final address = new Address()
      ..id = '2'
      ..street = 'Stockholm';
    addressBean.associateUser(address, user);
    await addressBean.insert(address);
  }

  // Manual One-To-One preload
  {
    final user = await userBean.find('2');
    print(user);
    user.address = await addressBean.findByUser(user.id);
    print(user);
  }

  // Preload many
  {
    final users = await userBean.getAll();
    print(users);
    await userBean.preloadAll(users);
    print(users);
  }

  // Cascaded One-To-One update
  {
    User user = await userBean.find('1', preload: true);
    user.name = 'Teja Hackborn';
    user.address.street = 'Stockholm, Sweden';
    await userBean.update(user, cascade: true);
  }

  // Fetch One-To-One relationship preloaded
  {
    final user = await userBean.find('1', preload: true);
    print(user);
  }

  // Cascaded removal of One-To-One relation
  await userBean.remove('1', true);

  // Remove addresses belonging to a User
  await addressBean.removeByUser('2');

  exit(0);
}