Belongs To relation defines that an entity is owned by a related entity on the exclusive matter. Example: a post belongs to an author, a comment belongs a post. Most belongsTo relations can be created using the inverse option of the declared hasOne or hasMany relation.
The entity will be always persisted after its related entity.
To define Belongs To relation using annotated entities extension use:
/** @Entity */
class Post
{
// ...
/** @BelongsTo(target = "User") */
protected $user;
}
You must properly handle the cases when the relation is not initialized (
null)!
By default, the ORM will generate an outer key in the relation object using the related entity's role and outer key (primary key by default) values. As result column and FK will be added to Post entity on user_id column.
| Option | Value | Comment |
|---|---|---|
| load | lazy/eager | Relation load approach. Defaults to lazy |
| cascade | bool | Automatically save related data with source entity. Defaults to true |
| nullable | bool | Defines if the relation can be nullable (child can have no parent). Defaults to false |
| innerKey | string | Inner key in source entity. Defaults to {relationName}_{outerKey} |
| outerKey | string | Outer key in the related entity. Defaults to the primary key |
| fkCreate | bool | Set to true to automatically create FK on innerKey. Defaults to true |
| fkAction | CASCADE, NO ACTION, SET NULL | FK onDelete and onUpdate action. Defaults to CASCADE |
| indexCreate | bool | Create an index on innerKey. Defaults to true |
Cycle will automatically save the related entity (unless cascade set to false).
$post = new Post();
$post->setUser(new User("Antony"));
$t = new \Cycle\ORM\Transaction($orm);
$t->persist($post);
$t->run();
You can only de-associate the related entity if the relation is defined as nullable. In other scenarios you will get an integrity exception:
$post = $orm->getRepository(Post::class)->findOne();
$post->setUser(null);
$t = new \Cycle\ORM\Transaction($orm);
$t->persist($post);
$t->run();
To access related data simply call the method load of your Post Select object:
$p = $orm->getRepository(Post::class)->select()->load('user')->wherePK(1)->fetchOne();
print_r($p->getAddress());
You can filter entity selection using related data, call the method with of your entity's Select to join the related entity table:
$posts = $orm->getRepository(Post::class)
->select()
->with('user')->where('user.status', 'active')
->fetchAll();
print_r($posts);
Select can automatically join related tables on the first where condition. The previous example can be rewritten:
$posts = $orm->getRepository(Post::class)
->select()
->where('user.status', 'active')
->fetchAll();
print_r($posts);