Morph to

The inverse of a polymorphic relationship, allowing a model to belong to multiple different parent types.

When to Use

Use MorphTo on the morphed model to define the inverse of MorphOne or MorphMany relations. Common examples:

• Comment belongs to Post or Video (commentable)
• Image belongs to User or Product (imageable)
• Activity belongs to User or Organization (trackable)

Database Structure

posts
-----
id        (primary key)
title
content

videos
------
id        (primary key)
title
url

comments
--------
id                  (primary key)
commentable_type    (stores parent model class: PostModel or VideoModel)
commentable_id      (stores parent model ID)
content
created_at

Defining the Relation

use Michalsn\CodeIgniterRelations\Relations\MorphTo;
use Michalsn\CodeIgniterRelations\Traits\HasRelations;

class CommentModel extends Model
{
    use HasRelations;

    protected $table = 'comments';
    protected $returnType = Comment::class;

    public function commentable(): MorphTo
    {
        return $this->morphTo('commentable');
    }
}

The 'commentable' parameter must match the morph name used in the parent models.

Custom Column Names

public function commentable(): MorphTo
{
    return $this->morphTo(
        'commentable',        // Morph name
        'custom_type',        // Custom type column
        'custom_id'           // Custom ID column
    );
}

Reading Data

Eager Loading

// Load comment with its parent (Post or Video)
$comment = model(CommentModel::class)->with('commentable')->find(1);

if ($comment->commentable instanceof Post) {
    echo "Comment on post: " . $comment->commentable->title;
} elseif ($comment->commentable instanceof Video) {
    echo "Comment on video: " . $comment->commentable->title;
}

// Load multiple comments with their parents
$comments = model(CommentModel::class)->with('commentable')->findAll();
foreach ($comments as $comment) {
    echo $comment->commentable->title; // Works for both Post and Video
}

Lazy Loading

$comment = model(CommentModel::class)->find(1);
echo $comment->commentable->title; // Parent is loaded automatically

With Query Constraints

$comments = model(CommentModel::class)
    ->with('commentable', fn($model) => $model->where('published', 1))
    ->findAll();

Writing Data

MorphTo is a read-only relation. You cannot save through this relation. Instead, use associate() and dissociate() to manage the relationship.

Associating with a Parent

Use associate() to link a morphed model to a parent:

$comment = model(CommentModel::class)->find(1);

// Associate with a post (using entity)
$post = model(PostModel::class)->find(5);
$comment->commentable()->associate($post);

// Associate with a video (using model class and ID)
$comment->commentable()->associate(VideoModel::class, 3);

Behavior:

• When passing an entity: Sets both commentable_type and commentable_id, updates in memory and database
• When passing model class and ID: Sets both fields, persists to database

Dissociating from Parent

Use dissociate() to remove the association:

$comment = model(CommentModel::class)->with('commentable')->find(1);
$comment->commentable()->dissociate();

// Both commentable_type and commentable_id are now null
echo $comment->commentable_type; // null
echo $comment->commentable; // null

Available Methods

Method	Description
associate($parent, $id = null)	Link to a parent (entity or model class + ID)
dissociate()	Remove the association (set morph fields to null)

Usage Patterns

Two Ways to Associate

$comment = model(CommentModel::class)->find(1);

// Method 1: Pass entity
$post = model(PostModel::class)->find(5);
$comment->commentable()->associate($post);

// Method 2: Pass model class and ID
$comment->commentable()->associate(VideoModel::class, 3);

Checking Parent Type

$comment = model(CommentModel::class)->with('commentable')->find(1);

if ($comment->commentable instanceof Post) {
    // Handle post comment
} elseif ($comment->commentable instanceof Video) {
    // Handle video comment
}

// Or check the type column directly
if ($comment->commentable_type === PostModel::class) {
    // Post comment
}