How do you use `object` cast handler for Entity?

[kenjis]

https://codeigniter4.github.io/CodeIgniter4/models/entities.html#property-casting

The object handler seems to expect the property to be set to an array. https://github.com/codeigniter4/CodeIgniter4/blob/0cd39937d7a8dbd8074237596024adce0fe3c2af/system/Entity/Cast/ObjectCast.php#L22-L25 https://github.com/codeigniter4/CodeIgniter4/blob/0cd39937d7a8dbd8074237596024adce0fe3c2af/tests/system/Entity/EntityTest.php#L439-L449

However, when setting an array, we cannot save that Entity to the database.

        $entity = new class () extends Entity {
            protected $casts = [
                'id'     => 'int',
                'active' => 'int-bool',
                'memo'   => 'object', // Use `object` handler
            ];
        };
        $model = new class () extends Model {
            protected $table         = 'users';
            protected $allowedFields = [
                'username', 'active', 'memo',
            ];
            protected $useTimestamps = true;
        };
        $entity->fill(['username' => 'johnsmith', 'active' => false, 'memo' => ['foo', 'bar']]);
        $model->save($entity); // CodeIgniter\Database\Exceptions\DatabaseException : Operand should contain 1 column(s)

How is this handler used in the first place?

[neznaika0]

@iRedds seems to have created it.

In my opinion, the conversion is not necessary. If you want to convert an array, then it should be in the database as JSON and json, json-array should be used. The concept of an object is too big, therefore it requires a custom Cast

It's probably worth adding @deprecated and replacing saving and conversion with JSON

[michalsn]

I have never used it. It is useless to me in the context of a relational database. Maybe for NoSQL or other scenarios, it might have some use.

[kenjis]

Yes, it seems useless in the context of a relational database.

But even for NoSQL, why don't you set an object to an entity, instead of an array?

[michalsn]

Good point. I honestly can't imagine a valid scenario 🤷‍♂️