Collection

Last updated: Fri, 29 Jan 2021 22:10

A collection is a set of entities.

Default collection class: Hector\Orm\Collection\Collection.

Personalized collection

You can personalize a collection for a specific entity. Uses attribute Hector\Orm\Attributes\Collection to do define the collection class.

use Hector\Orm\Attributes as Orm;
use Hector\Orm\Collection\Collection;
use Hector\Orm\Entity\MagicEntity;

#[Orm\Collection(MyEntityCollection::class)]
class MyEntity extends MagicEntity{
}

class MyEntityCollection extends Collection {
}

Edge loading

You can load specified foreign values of entities in one time with Collection::load() method.

// Do optimized SQL queries to retrieve foreigners
$collection->load(['foreign' => ['sub_foreign']]);

foreach($collection as $entity) {
    print $entity->foreign; // Do not SQL query
}

Refresh

In some cases, you need to refresh entities from collection with fresh data from database, Collection::refresh() do that with optimized requests.

$entity = $collection->first();
print $entity->field; // Output: 'bar'

$entity->field = 'foo';
print $entity->field; // Output: 'foo'

$collection->refresh();
print $entity->field; // Output: 'bar'

Save

You can save all entities modifications into database with method Collection::save().

Delete

You can delete all entities from database with method Collection::delete().

Json / Array

Hector\Orm\Collection\Collection class is a sub class of ArrayObject. So you can use methods of this parent class.

By default, the JSON result of serialization of a collection, is an array of entities. It's possible to extends the collection to define a personalized comportment.

To retrieve an array of the entities of collection, use the method: Collection::getArrayCopy().

Helpers

Filter

Collection allows filter entities with method Collection::filter(callable $callback): Generator, the result of method is a Generator.

$generator = $collection->filter(fn(Entity $entity) => $entity->isExpired());

foreach ($generator as $entity) {
    // ...
}

Collection allows to search an entity with method Collection::search(callable $callback): ?Entity.

$entity = $collection->search(fn(Entity $entity) => !$entity->isExpired());

if (null !== $entity) {
    // ...
}

Map

Collection allows to apply a function on each entity with method Collection::map(callable $callback): void.

$collection->map(fn(Entity $entity) => $entity->setViewed(true));

First

Collection allows to retrieve the first entity with method Collection::first(): ?Entity.

if (null !== ($entity = $collection->first())) {
    // ...
}

Contains

You can test if a collection contains an entity object with method Collection::contains(Entity $entity): bool. The comparison is strict, so the comparison two entities whose represent the same row is false.