Source-generated ORM with relations (one-to-one, one-to-many, many-to-many), preloading, cascading, polymorphic relations, etc
- Relationships
- Preloads
- Cascading
- Cascaded inserts
- Cascaded updates
- Cascaded removals
- Migration
- Polymorphic relations
- Composite primary keys
- Composite foreign keys
class User {
@PrimaryKey()
String id;
String name;
static const String tableName = '_user';
String toString() => "User($id, $name)";
}A Bean performs database actions on behalf of the model. In this case,
UserBean performs actions for User model. Much of the Bean's
functionality will be source generated.
@GenBean()
class UserBean extends Bean<User> with _UserBean {
UserBean(Adapter adapter) : super(adapter);
}jaguar_orm use source_gen and jaguar_orm_gen to generate bean logic from bean specification.
Add the following dependencies to dev_dependencies.
build_runner:
jaguar_orm_gen:
Run the following command to generate Bean logic:
pub run build_runner buildWe will use PostgreSQL for this tutorial. PgAdapter is found in the
package jaguar_query_postgres.
final PgAdapter _adapter =
new PgAdapter('example', username: 'postgres', password: 'dart_jaguar');
await _adapter.connect();Beans internally use jaguar_query's Adapter interface to talk to
database. Lets create an instance of UserBean.
final userBean = new UserBean(_adapter);await userBean.drop();await userBean.createTable();
await userBean.insert(new User()
..id = '1'
..name = 'teja');User user = await userBean.find('1');List<User> users = await userBean.getAll();User user = await userBean.find('1');
user.name = 'teja hackborn';
await userBean.update(user);await userBean.remove('1');await userBean.removeAll();class User {
@PrimaryKey()
String id;
String name;
@HasOne(AddressBean)
Address address;
static const String tableName = '_user';
String toString() => "User($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:dart_jaguar@localhost/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);
}
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