Draft of possible immutable append-only entities

Article1.php

<?php

class Article 
{
	/** @var \DateTime */
	private $createdAt;

	/** @var ArticleHistory[] */
	private $historyChanges;


	public function __construct($text)
	{
		$this->createdAt = new \DateTime;
		$this->updateText($text);
	}


	public function updateText($text)
	{
		$this->historyChanges[] = new ArticleHistory($this, $text);
	}


	public function text()
	{
		// případně jiná logika, na vytáhnutí poslední změny
		return $this->historyChanges->last()->text();
	}
}

class ArticleHistory
{
	/** @var Article */
	private $article;

	/** @var \DateTime */
	private $createdAt;

	/** @var string */
	private $text;


	public function __construct(Article $article, $text)
	{
		$this->createdAt = new \DateTime;
		$this->article = $article;
		$this->text = $text;
	}


	public function text()
	{
		return $this->text;
	}
}

Article2.php

<?php

class Article
{
	/** @var UuidInterface */
	private $id; // primary key

	/** @var UuidInterface */
	private $articleId; // non-unique

	/** @var string */
	private $text;


	public function __construct($text, $articleId = NULL)
	{
		$this->id = Uuid::uuid4();
		$this->articleId = $articleId ? $articleId : Uuid::uuid4();
		$this->text = $text;
	}


	public function updateText($text)
	{
		return new Article($text, $this->articleId);
	}


	public function text()
	{
		return $this->text;
	}
}

gistfile1.txt

Possible solution - dispatch domain event, something like "ArticleEdited" every time any editation happens -> this domain event could be persisted and saved into other persistence storage type (nosql etc.).