README

This library is an abstraction on top of Doctrine with the intention to remove all implicit states.

Managing the state in an application can become hard when the codebase grows and states (especially implicit ones) is one of the source of bugs in applications.

Doctrine is usually the default choice (not an actual fact) when interacting with databases as it comes bundled with Symfony. Its interface cover many use cases but expose many implicit states such as transactions or cursors in collections.

This is solved here by using principles from the functional programming paradigm.

Installation

composer require innmind/doctrine

Design choices

Click to expand

`Sequence` vs `Set`

Set has been discarded for this library as the unicity of entities cannot be guaranted from the returned collections. It also would prevent the use of the map function as many entities may be mapped to a single new value, this may lead to unexpected behaviour for newcomers to such paradigm. This is mainly why the choice has been toward Sequence.

In case you really want to use sets, you may use innmind/immutable.

Enforcing the use of an `Id`

Doctrine allows you to generate an id for you when your entities are persisted. This is an implicit state change.

In order to avoid this implicit you need to specify the id before persisting your entities. This prevents you from relying on the auto generated id from your database as you can't avoid collisions.

The unique solution (that I'm aware of) is to use UUIDs. The Id provided by this library use them so you don't have to think of it anymore.

A single `Id` class for all entities

This is no longer a problem as it is provided with a template understood by vimeo/psalm.

No `flush` method on the `Manager`

Being free to call the persist and flush methods when you wish it opens the door to implicit states in your codebase. You may end up either flushing unwanted persisted entities (persist calls before an error occured) or forgetting to flush persisted entities (resulting in lost state change).

Here this is avoided by forcing to execute all mutations in a given context (via Manager::mutate() and Manager::transaction()). So it's always all or nothing.

Usage

All the use cases below use the code declared in the example folder.

Pre-requisite for all use cases:

use Innmind\Doctrine\{
    Manager,
    Sort,
};
use Example\Innmind\Doctrine\User;

$manager = Manager::of($entityManager);

Fetching all entities from the database

$manager
    ->repository(User::class)
    ->all()
    ->sort('username', Sort::asc)
    ->fetch()
    ->foreach(function(User $user): void {
        echo $user->username()."\n";
    });

Note: The queries are delayed to the last moment possible to leverage the database as most as possible.

Pagination

$numberOfElementPerPage = 10;
$manager
    ->repository(User::class)
    ->all()
    ->sort('username', Sort::asc)
    ->drop($page * $numberOfElementPerPage)
    ->take($numberOfElementPerPage)
    ->fetch()
    ->foreach(function(User $user): void {
        echo $user->username()."\n";
    });

Filtering

It uses the Specification pattern (normalized in the library innmind/specification).

use Example\Innmind\Doctrine\Username;

$manager
    ->repository(User::class)
    ->matching(
        Username::of('alice')->or(
            Username::of('jane'),
        ),
    )
    ->sort('username', Sort::asc)
    ->drop(20)
    ->take(10)
    ->fetch()
    ->foreach(function(User $user): void {
        echo $user->username()."\n";
    });

This example is the equivalent of SELECT * FROM user WHERE username = 'alice' OR username = 'jane' ORDER BY username OFFSET 20 LIMIT 10.

Note: This chain of method calls result once again in a single database call.

Adding new entities

use Innmind\Doctrine\Id;
use Innmind\Immutable\Either;

$user = $manager->mutate(function($manager): Either {
    $user = new User(
        Id::new(),
        'someone',
    );
    $manager
        ->repository(User::class)
        ->add($user);

    return Either::right($user);
});

If you try to call Repository::add() or Repository::remove() outside the function it will raise an exception.

Note: If the function throws an exception or an Either::left is returned then nothing will be flushed to the database.

Transactions

$manager->transaction(function($manager, $flush): Either {
    $progress = 0;
    $repository = $manager->repository(User::class);

    foreach ($someSource as $args) {
        $repository->add(new User(...$args));
        ++$progress;

        if ($progress % 20 === 0) {
            // flush entities to the database every 20 additions
            $flush();
        }
    }

    return Either::right(null);
});

Note: Call the $flush function only when in a context of imports as it will detach all the entities from entity manager, meaning if you kept references to entities they will no longer be understood by doctrine

Accessing the values inside a sequence

Sometimes you may want to manipulate an array so it can be used with php functions such as json_encode.

use Symfony\Component\HttpFoundation\JsonResponse;

/** @var list<array{username: string, registerIndex: int}> */
$data = $manager
    ->repository(User::class)
    ->all()
    ->sort('registerIndex', Sort::asc)
    ->fetch()
    ->map(static fn(User $user): array => [
        'username' => $user->username(),
        'registerIndex' => $user->registerIndex(),
    ])
    ->toList();

new JsonResponse($data);

Filtering on relations

You can specify the property of an entity relationship in a specification property field.

use Example\Innmind\Doctrine\Child;

$users = $manager
    ->repository(User::class)
    ->matching(
        Child::of('alice')->or(
            Child::of('jane'),
        ),
    );

The Child specification use the property children.username thus specifying the username of a user's children.

Note: for now only one level relationship is allowed in a specification property.

Lazy loading collections

In certain cases the amount of entities you will fetch won't fit in memory. To still work with this king of scenario you need to use a lazy Sequence and perform periodic clears.

$_ = $manager
    ->repository(User::class)
    ->all()
    ->lazy() // instruct to load one entity at a time
    ->fetch()
    ->foreach(function($user) use ($manager) {
        doStuff($user);
        // this clear is important to make doctrine forget about the loaded
        // entities and will consequently free memory
        $manager->clear();
    });

Note: this feature won't work however if you use bi-directional relationships in your entities, for some reason doctrine won't free memory.

Note 2: you should only use this feature when reading data. Using this in a write context may have unexpected side effects!

innmind / doctrine

Maintainers

Details

README

Installation

Design choices

`Sequence` vs `Set`

Enforcing the use of an `Id`

A single `Id` class for all entities

No `flush` method on the `Manager`

Usage

Fetching all entities from the database

Pagination

Filtering

Adding new entities

Transactions

Accessing the values inside a sequence

Filtering on relations

Lazy loading collections

innmind / doctrine

Maintainers

Details

README

Installation

Design choices

Sequence vs Set

Enforcing the use of an Id

A single Id class for all entities

No flush method on the Manager

Usage

Fetching all entities from the database

Pagination

Filtering

Adding new entities

Transactions

Accessing the values inside a sequence

Filtering on relations

Lazy loading collections

`Sequence` vs `Set`

Enforcing the use of an `Id`

A single `Id` class for all entities

No `flush` method on the `Manager`