ORM showcase

Lemonade Blog

A small blog powered by Doctrine ORM and SQLite.

Doctrine ORM · SQLite · ManyToMany

Live ORM result

Latest articles

1234 articles

Deploying a Lemonade application — field note 0051

A focused deployment checklist keeps configuration aligned. This deterministic field note expands the demo dataset.

Doctrine ORM as an application integration — field note 0052

Doctrine stays in app code and resolves only when it is needed. This deterministic field note expands the demo dataset.

Caching reconstructible data — field note 0053

Use cache for values that can be rebuilt safely. This deterministic field note expands the demo dataset.

Safer image uploads — field note 0054

An upload profile centralizes limits and validation. This deterministic field note expands the demo dataset.

CLI commands for repeatable work — field note 0055

Small command classes keep operational work discoverable. This deterministic field note expands the demo dataset.

Designing clear API endpoints — field note 0056

API providers keep endpoint concerns together. This deterministic field note expands the demo dataset.

Queue work after the request — field note 0057

Messages let slow work continue in a CLI worker. This deterministic field note expands the demo dataset.

Database schema belongs to migrations — field note 0058

Keep application schema changes explicit and reviewable. This deterministic field note expands the demo dataset.

Validation once at the boundary — field note 0059

Validate input before it reaches write services. This deterministic field note expands the demo dataset.

Middleware protects the HTTP flow — field note 0060

Middleware keeps request policies close to the HTTP boundary. This deterministic field note expands the demo dataset.

How this blog works

Doctrine ORM integration behind the example

The paginated blog feed reads current-page IDs through toIterable(); a bounded graph batch then loads authors and tags without N+1 queries.

Provider wiring

DoctrineServiceProvider.php

Registers Doctrine as a regular application service through a Lemonade provider.

DoctrineServiceProvider.php
PHP
<?php

declare(strict_types=1);

namespace App\Providers;

use App\Repository\OrmDemoArticleRepository;
use App\Repository\OrmDemoAuthorRepository;
use App\Repository\OrmDemoTagRepository;
use App\Services\DoctrineEntityManagerFactory;
use App\Services\OrmDemoService;
use Doctrine\ORM\EntityManagerInterface;
use Lemonade\Framework\Container\ContainerInterface;
use Lemonade\Framework\Core\ServiceProviderInterface;

final class DoctrineServiceProvider implements ServiceProviderInterface
{
    public function register(ContainerInterface $container): void
    {
        $container->singleton(DoctrineEntityManagerFactory::class, DoctrineEntityManagerFactory::class);
        $container->singleton(
            EntityManagerInterface::class,
            static fn (ContainerInterface $container): EntityManagerInterface => $container
                ->get(DoctrineEntityManagerFactory::class)
                ->create(),
        );
        $container->set(OrmDemoArticleRepository::class, OrmDemoArticleRepository::class);
        $container->set(OrmDemoTagRepository::class, OrmDemoTagRepository::class);
        $container->set(OrmDemoAuthorRepository::class, OrmDemoAuthorRepository::class);
        $container->singleton(OrmDemoService::class, OrmDemoService::class);
    }
}
Article entity

OrmDemoArticle.php

Maps multiple authors and multiple tags through ManyToMany associations.

OrmDemoArticle.php
PHP
<?php

declare(strict_types=1);

namespace App\Entity;

use DateTimeImmutable;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;
use Doctrine\ORM\Mapping as ORM;
use InvalidArgumentException;

#[ORM\Entity]
#[ORM\Table(name: 'orm_demo_articles')]
final class OrmDemoArticle
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column(type: 'integer')]
    private ?int $id = null;

    #[ORM\Column(type: 'string', length: 255)]
    private string $title;

    #[ORM\Column(type: 'text')]
    private string $perex;

    /** @var Collection<int, OrmDemoAuthor> */
    #[ORM\ManyToMany(targetEntity: OrmDemoAuthor::class, inversedBy: 'articles', cascade: ['persist'])]
    #[ORM\JoinTable(name: 'orm_demo_article_authors')]
    private Collection $authors;

    #[ORM\Column(type: 'datetime_immutable')]
    private DateTimeImmutable $createdAt;

    /** @var Collection<int, OrmDemoTag> */
    #[ORM\ManyToMany(targetEntity: OrmDemoTag::class, inversedBy: 'articles', cascade: ['persist'])]
    #[ORM\JoinTable(name: 'orm_demo_article_tags')]
    private Collection $tags;

    /**
     * @param non-empty-list<OrmDemoAuthor> $authors
     */
    public function __construct(string $title, string $perex, array $authors, DateTimeImmutable $createdAt)
    {
        if ($authors === []) {
            throw new InvalidArgumentException('An ORM demo article must have at least one author.');
        }

        $this->title = $title;
        $this->perex = $perex;
        $this->createdAt = $createdAt;
        $this->authors = new ArrayCollection();
        $this->tags = new ArrayCollection();

        foreach ($authors as $author) {
            $this->addAuthor($author);
        }
    }

    public function id(): ?int
    {
        return $this->id;
    }

    public function title(): string
    {
        return $this->title;
    }

    public function perex(): string
    {
        return $this->perex;
    }

    /** @return list<OrmDemoAuthor> */
    public function authors(): array
    {
        return $this->authors->toArray();
    }

    public function addAuthor(OrmDemoAuthor $author): void
    {
        if (!$this->authors->contains($author)) {
            $this->authors->add($author);
        }
    }

    public function createdAt(): DateTimeImmutable
    {
        return $this->createdAt;
    }

    /** @return Collection<int, OrmDemoTag> */
    public function tags(): Collection
    {
        return $this->tags;
    }

    public function addTag(OrmDemoTag $tag): void
    {
        if (!$this->tags->contains($tag)) {
            $this->tags->add($tag);
        }
    }
}
Author entity

OrmDemoAuthor.php

Authors are separate entities identified by a unique nickname.

OrmDemoAuthor.php
PHP
<?php
declare(strict_types=1);

namespace App\Entity;

use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;
use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity]
#[ORM\Table(name: 'orm_demo_authors')]
final class OrmDemoAuthor
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column(type: 'integer')]
    private ?int $id = null;

    #[ORM\Column(type: 'string', length: 80, unique: true)]
    private string $nickname;

    /** @var Collection<int, OrmDemoArticle> */
    #[ORM\ManyToMany(targetEntity: OrmDemoArticle::class, mappedBy: 'authors')]
    private Collection $articles;

    public function __construct(string $nickname)
    {
        $this->nickname = $nickname;
        $this->articles = new ArrayCollection();
    }

    public function id(): ?int
    {
        return $this->id;
    }

    public function nickname(): string
    {
        return $this->nickname;
    }
}
Tag entity

OrmDemoTag.php

Tags are shared entities connected to articles through a join table.

OrmDemoTag.php
PHP
<?php

declare(strict_types=1);

namespace App\Entity;

use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;
use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity]
#[ORM\Table(name: 'orm_demo_tags')]
final class OrmDemoTag
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column(type: 'integer')]
    private ?int $id = null;

    #[ORM\Column(type: 'string', length: 80)]
    private string $name;

    #[ORM\Column(type: 'string', length: 80, unique: true)]
    private string $slug;

    /** @var Collection<int, OrmDemoArticle> */
    #[ORM\ManyToMany(targetEntity: OrmDemoArticle::class, mappedBy: 'tags')]
    private Collection $articles;

    public function __construct(string $name, string $slug)
    {
        $this->name = $name;
        $this->slug = $slug;
        $this->articles = new ArrayCollection();
    }

    public function id(): ?int
    {
        return $this->id;
    }

    public function name(): string
    {
        return $this->name;
    }

    public function slug(): string
    {
        return $this->slug;
    }
}
Repository and pagination

OrmDemoArticleRepository.php

Combines optional filters with SQL-level pagination and avoids N+1 queries.

OrmDemoArticleRepository.php
PHP
<?php

declare(strict_types=1);

namespace App\Repository;

use App\Entity\OrmDemoArticle;
use App\Services\DoctrineEntityManagerFactory;
use Doctrine\ORM\EntityManagerInterface;

final class OrmDemoArticleRepository
{
    private const GRAPH_BATCH_SIZE = 25;

    public function __construct(private readonly DoctrineEntityManagerFactory $entityManagerFactory)
    {
    }

    public function paginate(int $page, int $perPage, ?string $tag = null, ?string $author = null): OrmDemoArticlePage
    {
        $perPage = max(1, $perPage);
        $count = $this->entityManager()
            ->createQueryBuilder()
            ->select('COUNT(DISTINCT article.id)')
            ->from(OrmDemoArticle::class, 'article');

        if ($tag !== null) {
            $count
                ->innerJoin('article.tags', 'tag')
                ->andWhere('tag.slug = :tag')
                ->setParameter('tag', $tag);
        }

        if ($author !== null) {
            $count
                ->innerJoin('article.authors', 'author')
                ->andWhere('author.nickname = :author')
                ->setParameter('author', $author);
        }

        $total = (int) $count->getQuery()->getSingleScalarResult();
        $page = min(max(1, $page), max(1, (int) ceil($total / $perPage)));

        $idsQuery = $this->entityManager()
            ->createQueryBuilder()
            ->select('DISTINCT article.id AS id')
            ->from(OrmDemoArticle::class, 'article');
        if ($tag !== null) {
            $idsQuery
                ->innerJoin('article.tags', 'tag')
                ->andWhere('tag.slug = :tag')
                ->setParameter('tag', $tag);
        }

        if ($author !== null) {
            $idsQuery
                ->innerJoin('article.authors', 'author')
                ->andWhere('author.nickname = :author')
                ->setParameter('author', $author);
        }

        $idsQuery
            ->orderBy('article.createdAt', 'DESC')
            ->addOrderBy('article.id', 'DESC')
            ->setFirstResult(($page - 1) * $perPage)
            ->setMaxResults($perPage);

        $articles = (function () use ($idsQuery): iterable {
            $entityManager = $this->entityManager();
            $ids = [];

            foreach ($idsQuery->getQuery()->toIterable() as $row) {
                $ids[] = (int) $row['id'];

                if (count($ids) === self::GRAPH_BATCH_SIZE) {
                    yield from $this->fetchGraphBatch($entityManager, $ids);
                    $ids = [];
                    $entityManager->clear();
                }
            }

            if ($ids !== []) {
                yield from $this->fetchGraphBatch($entityManager, $ids);
                $entityManager->clear();
            }
        })();

        return new OrmDemoArticlePage($articles, $total, $page);
    }

    /** @param list<int> $ids @return iterable<OrmDemoArticle> */
    private function fetchGraphBatch(EntityManagerInterface $entityManager, array $ids): iterable
    {
        /** @var list<OrmDemoArticle> $fetched */
        $fetched = $entityManager->createQueryBuilder()
            ->select('article, author, tag')
            ->from(OrmDemoArticle::class, 'article')
            ->leftJoin('article.authors', 'author')
            ->leftJoin('article.tags', 'tag')
            ->where('article.id IN (:ids)')
            ->setParameter('ids', $ids)
            ->getQuery()
            ->getResult();
        $byId = [];

        foreach ($fetched as $article) {
            $byId[$article->id() ?? 0] = $article;
        }

        foreach ($ids as $id) {
            if (isset($byId[$id])) {
                yield $byId[$id];
            }
        }
    }

    public function hasArticles(): bool
    {
        return $this->entityManager()->getRepository(OrmDemoArticle::class)->count([]) > 0;
    }

    public function add(OrmDemoArticle $article): void
    {
        $this->entityManager()->persist($article);
        $this->entityManager()->flush();
    }

    /** @param iterable<OrmDemoArticle> $articles */
    public function addAll(iterable $articles, int $batchSize): void
    {
        $entityManager = $this->entityManager();
        $processed = 0;

        $batchSize = max(1, $batchSize);

        foreach ($articles as $article) {
            $entityManager->persist($article);
            ++$processed;

            if ($processed % $batchSize === 0) {
                $entityManager->flush();
            }
        }

        $entityManager->flush();
    }

    private function entityManager(): EntityManagerInterface
    {
        return $this->entityManagerFactory->create();
    }
}

How filtering works

Articles can have multiple authors and multiple tags. Both associations are mapped in Doctrine ORM as ManyToMany. When filtering by author, Doctrine connects articles through the join table orm_demo_article_authors and selects them by author.nickname. When filtering by tag, it uses the join table orm_demo_article_tags with a condition on tag.slug. Both filters can be combined.