---

name: symfony-sk:api-entity-relation description: Add a relation between two existing entities. Use when linking entities with ManyToOne, OneToMany, or ManyToMany relationships. allowed-tools: Read, Write, Edit, Glob, Grep

API Entity Relation Skill

Mission

Add a relationship between two existing Doctrine entities.

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Relation Types

ManyToOne (N:1)

One entity references another. Most common.

CopyTask -> Event (many tasks belong to one event)

OneToMany (1:N)

Inverse of ManyToOne. Collection on the "one" side.

CopyEvent -> Tasks (one event has many tasks)

ManyToMany (N:N)

Both sides have collections. Requires join table.

CopyEvent <-> Tags (events have tags, tags have events)

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Templates

ManyToOne (owning side)

Add to the entity that holds the foreign key:

Copyuse App\Entity\<Target>;

#[ORM\ManyToOne(targetEntity: <Target>::class)]
#[ORM\JoinColumn(nullable: false)]
private ?<Target> $<target> = null;

public function get<Target>(): ?<Target>
{
    return $this-><target>;
}

public function set<Target>(?<Target> $<target>): static
{
    $this-><target> = $<target>;
    return $this;
}

OneToMany (inverse side)

Add to the entity that has the collection:

Copyuse Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;

// In constructor
$this-><targets> = new ArrayCollection();

// Property
#[ORM\OneToMany(targetEntity: <Target>::class, mappedBy: '<source>', cascade: ['persist', 'remove'])]
private Collection $<targets>;

public function get<Targets>(): Collection
{
    return $this-><targets>;
}

public function add<Target>(<Target> $<target>): static
{
    if (!$this-><targets>->contains($<target>)) {
        $this-><targets>->add($<target>);
        $<target>->set<Source>($this);
    }
    return $this;
}

public function remove<Target>(<Target> $<target>): static
{
    if ($this-><targets>->removeElement($<target>)) {
        if ($<target>->get<Source>() === $this) {
            $<target>->set<Source>(null);
        }
    }
    return $this;
}

ManyToMany

Owning side:

Copy#[ORM\ManyToMany(targetEntity: <Target>::class, inversedBy: '<sources>')]
#[ORM\JoinTable(name: '<source>_<target>')]
private Collection $<targets>;

Inverse side:

Copy#[ORM\ManyToMany(targetEntity: <Source>::class, mappedBy: '<targets>')]
private Collection $<sources>;

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Process

1. Identify relation type (ManyToOne, OneToMany, ManyToMany)
2. Identify owning side (the one with the foreign key)
3. Add property + methods to owning side
4. Add inverse property + methods if bidirectional
5. Add constructor initialization for collections
6. Run dsu to update schema

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After Modification

Copyssh <host> "docker exec <code>-api ./scripts/dsu"

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Checklist

• Relation type identified
• Owning side determined
• Property added with ORM attributes
• Getter/setter added
• Constructor initializes collections (if applicable)
• Inverse side added (if bidirectional)
• mappedBy / inversedBy match property names
• Schema updated via dsu