Angel’s ORM ships with support for running database migrations, using a systemmodeled over that of Laravel.

An example is shown below:

class UserMigration implements Migration {
  @override
  void up(Schema schema) {
    schema.create('users', (table) {
      table
        ..serial('id').primaryKey()
        ..varChar('username', length: 32).unique()
        ..varChar('password')
        ..boolean('account_confirmed').defaultsTo(false);
    });
  }
  @override
  void down(Schema schema) {
    schema.drop('users');
  }
}

Migrations can be used to either create, alter, or drop database tables.

For more in-depth documentation, consult the angel_migration documentation:

https://github.com/angel-dart/migration

If you use angel_orm_generator, then a migration will be generated by default for each classannotated with @orm.

To disable this:

@Orm(generateMigrations: false)
abstract class _MyModel extends Model {}

Running Migrations

Using package:angel_migration_runner, we can create executables that run our database migrations:

import 'package:angel_migration_runner/angel_migration_runner.dart';
import 'package:angel_migration_runner/postgres.dart';
import 'package:postgres/postgres.dart';
import '../../angel_migration/example/todo.dart';
var migrationRunner = PostgresMigrationRunner(
  PostgreSQLConnection('127.0.0.1', 5432, 'test'),
  migrations: [
    UserMigration(),
    TodoMigration(),
  ],
);

Running this file will produce output like the following:

Executes Angel migrations.
Usage: migration_runner <command> [arguments]
Global options:
-h, --help    Print this usage information.
Available commands:
  help       Display help information for migration_runner.
  refresh    Resets the database, and then re-runs all migrations.
  reset      Resets the database.
  rollback   Undoes the last batch of migrations.
  up         Runs outstanding migrations.
Run "migration_runner help <command>" for more information about a command.

The migration runner keeps track of a migrations table, in order to be ableto keep track of which migrations it has run.