orm
Source-generated PostgreSQL ORM for use with the Angel framework. Now you can combine the power and flexibility of Angel with a strongly-typed ORM.
Documentation for migrations can be found here: https://angel-dart.gitbook.io/angel/v/2.x/orm/migrations
Usage
You'll need these dependencies in your pubspec.yaml:
dependencies:
angel_orm: ^2.0.0-dev
dev_dependencies:
angel_orm_generator: ^2.0.0-dev
build_runner: ^1.0.0package:angel_orm_generator exports a class that you can include
in a package:build flow:
-
PostgresOrmGenerator- Fueled bypackage:source_gen; include this within aSharedPartBuilder.
However, it also includes a build.yaml that builds ORM files automatically, so you shouldn't
have to do any configuration at all.
Models
The ORM works best when used with package:angel_serialize:
library angel_orm.test.models.car;
import 'package:angel_migration/angel_migration.dart';
import 'package:angel_model/angel_model.dart';
import 'package:angel_orm/angel_orm.dart';
import 'package:angel_serialize/angel_serialize.dart';
part 'car.g.dart';
@serializable
@orm
abstract class _Car extends Model {
String get make;
String get description;
bool get familyFriendly;
DateTime get recalledAt;
}
// You can disable migration generation.
@Orm(generateMigrations: false)
abstract class _NoMigrations extends Model {}Models can use the @SerializableField() annotation; package:angel_orm obeys it.
After building, you'll have access to a Query class with strongly-typed methods that
allow to run asynchronous queries without a headache.
Remember that if you don't need automatic id-and-date fields, you can
simply just not extend Model:
@Serializable(autoIdAndDateFields: false)
abstract class _ThisIsNotAnAngelModel {
@primaryKey
String get username;
}Example
MVC just got a whole lot easier:
import 'package:angel_framework/angel_framework.dart';
import 'package:angel_orm/angel_orm.dart';
import 'car.dart';
import 'car.orm.g.dart';
/// Returns an Angel plug-in that connects to a database, and sets up a controller connected to it...
AngelConfigurer connectToCarsTable(QueryExecutor executor) {
return (Angel app) async {
// Register the connection with Angel's dependency injection system.
//
// This means that we can use it as a parameter in routes and controllers.
app.container.registerSingleton(executor);
// Attach the controller we create below
await app.mountController<CarController>();
};
}
@Expose('/cars')
class CarController extends Controller {
// The `executor` will be injected.
@Expose('/recalled_since_2008')
carsRecalledSince2008(QueryExecutor executor) {
// Instantiate a Car query, which is auto-generated. This class helps us build fluent queries easily.
var query = new CarQuery();
query.where
..familyFriendly.equals(false)
..recalledAt.year.greaterThanOrEqualTo(2008);
// Shorter syntax we could use instead...
query.where.recalledAt.year <= 2008;
// `get()` returns a Future<List<Car>>.
var cars = await query.get(executor);
return cars;
}
@Expose('/create', method: 'POST')
createCar(QueryExecutor executor) async {
// `package:angel_orm` generates a strongly-typed `insert` function on the query class.
// Say goodbye to typos!!!
var query = new CarQuery();
query.values
..familyFriendly = true
..make 'Honda';
var car = query.insert(executor);
// Auto-serialized using code generated by `package:angel_serialize`
return car;
}
}Relations
angel_orm supports the following relationships:
-
@HasOne()(one-to-one) -
@HasMany()(one-to-many) -
@BelongsTo()(one-to-one) -
@ManyToMany()(many-to-many, using a "pivot" table)
The annotations can be abbreviated with the default options (ex. @hasOne), or supplied
with custom parameters (ex. @HasOne(foreignKey: 'foreign_id')).
@serializable
@orm
abstract class _Author extends Model {
@hasMany // Use the defaults, and auto-compute `foreignKey`
List<_Book> books;
// Also supports parameters...
@HasMany(localKey: 'id', foreignKey: 'author_id', cascadeOnDelete: true)
List<_Book> books;
@SerializableField(alias: 'writing_utensil')
@hasOne
_Pen pen;
}The relationships will "just work" out-of-the-box, following any operation. For example,
after fetching an Author from the database in the above example, the books field would
be populated with a set of deserialized Book objects, also fetched from the database.
Relationships use joins when possible, but in the case of @HasMany(), two queries are used:
- One to fetch the object itself
- One to fetch a list of related objects
Many to Many Relations
A many-to-many relationship can now be modeled like so.
RoleUser in this case is a pivot table joining User and Role.
Note that in this case, the models must reference the private classes (_User, etc.), because the canonical versions (User, etc.) are not-yet-generated:
@serializable
@orm
abstract class _User extends Model {
String get username;
String get password;
String get email;
@ManyToMany(_RoleUser)
List<_Role> get roles;
}
@serializable
@orm
abstract class _RoleUser {
@belongsTo
_Role get role;
@belongsTo
_User get user;
}
@serializable
@orm
abstract class _Role extends Model {
String name;
@ManyToMany(_RoleUser)
List<_User> get users;
}TLDR:
- Make a pivot table, C, between two tables, table A and B
- C should
@belongsToboth A and B. C should not extendModel. - A should have a field:
@ManyToMany(_C) List<_B> get b; - B should have a field:
@ManyToMany(_C) List<_A> get a;
Columns
Use a @Column() annotation to change how a given field is handled within the ORM.
Column Types
Using the @Column() annotation, it is possible to explicitly declare the data type of any given field:
@serializable
@orm
abstract class _Foo extends Model {
@Column(type: ColumnType.bigInt)
int bar;
}Indices
Columns can also have an index:
@serializable
@orm
abstract class _Foo extends Model {
@Column(index: IndexType.primaryKey)
String bar;
}Default Values
It is also possible to specify the default value of a field. Note that this only works with primitive objects.
If a default value is supplied, the SqlMigrationBuilder will include
it in the generated schema. The PostgresOrmGenerator ignores default values;
it does not need them to function properly.
@serializable
@orm
abstract class _Foo extends Model {
@Column(defaultValue: 'baz')
String bar;
}
