267 lines
7.2 KiB
Markdown
267 lines
7.2 KiB
Markdown
# orm
|
|
[](https://pub.dartlang.org/packages/angel_orm)
|
|
[](https://travis-ci.org/angel-dart/orm)
|
|
|
|
Source-generated PostgreSQL ORM for use with the
|
|
[Angel framework](https://angel-dart.github.io).
|
|
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](#usage)
|
|
* [Model Definitions](#models)
|
|
* [MVC Example](#example)
|
|
* [Relationships](#relations)
|
|
* [Many-to-Many Relationships](#many-to-many-relations)
|
|
* [Columns (`@Column(...)`)](#columns)
|
|
* [Column Types](#column-types)
|
|
* [Indices](#indices)
|
|
* [Default Values](#default-values)
|
|
|
|
# Usage
|
|
You'll need these dependencies in your `pubspec.yaml`:
|
|
```yaml
|
|
dependencies:
|
|
angel_orm: ^2.0.0-dev
|
|
dev_dependencies:
|
|
angel_orm_generator: ^2.0.0-dev
|
|
build_runner: ^1.0.0
|
|
```
|
|
|
|
`package:angel_orm_generator` exports a class that you can include
|
|
in a `package:build` flow:
|
|
* `PostgresOrmGenerator` - Fueled by `package:source_gen`; include this within a `SharedPartBuilder`.
|
|
|
|
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`:
|
|
|
|
```dart
|
|
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`:
|
|
|
|
```dart
|
|
@Serializable(autoIdAndDateFields: false)
|
|
abstract class _ThisIsNotAnAngelModel {
|
|
@primaryKey
|
|
String get username;
|
|
}
|
|
```
|
|
|
|
# Example
|
|
|
|
MVC just got a whole lot easier:
|
|
|
|
```dart
|
|
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')`).
|
|
|
|
```dart
|
|
@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:
|
|
|
|
```dart
|
|
@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:
|
|
1. Make a pivot table, C, between two tables, table A and B
|
|
2. C should `@belongsTo` both A and B. C *should not* extend `Model`.
|
|
3. A should have a field: `@ManyToMany(_C) List<_B> get b;`
|
|
4. B should have a field: `@ManyToMany(_C) List<_A> get a;`
|
|
|
|
Test: https://raw.githubusercontent.com/angel-dart/orm/master/angel_orm_generator/test/many_to_many_test.dart
|
|
|
|
# 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:
|
|
|
|
```dart
|
|
@serializable
|
|
@orm
|
|
abstract class _Foo extends Model {
|
|
@Column(type: ColumnType.bigInt)
|
|
int bar;
|
|
}
|
|
```
|
|
|
|
## Indices
|
|
Columns can also have an `index`:
|
|
|
|
```dart
|
|
@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.
|
|
|
|
```dart
|
|
@serializable
|
|
@orm
|
|
abstract class _Foo extends Model {
|
|
@Column(defaultValue: 'baz')
|
|
String bar;
|
|
}
|
|
```
|