dataMapper.php

<?php

/**
 * Class Mapper
 */
abstract class Mapper
{
    /**
     * @var PDO
     */
    private $connection;
    /**
     * @var
     */
    protected $table;

    /**
     * @param PDO $connection
     */
    public function __construct(PDO $connection)
    {
        $this->connection = $connection;
    }

    /**
     * @param array $attributes
     * @return Entity
     */
    public static function createEntity(array $attributes)
    {
        return new Book($attributes);
    }

    /**
     * @param Entity $entity
     */
    public function insert(Entity $entity)
    {

    }

    /**
     * @param Entity $entity
     */
    public function update(Entity $entity)
    {

    }

    /**
     * @param Entity $entity
     */
    public function delete(Entity $entity)
    {

    }

    /**
     * @param array $condition
     * @return Entity[]
     */
    public function findAll(array $condition)
    {

    }

    /**
     * @param array $condition
     * @return Entity
     */
    public function findOne(array $condition)
    {

    }
}

/**
 * Class BooksMapper
 */
class BooksMapper extends Mapper
{
    /**
     * @var string
     */
    protected $table = 'books';
}

/**
 * Class Entity
 */
abstract class Entity
{
    /**
     * @var array
     */
    protected $attributes = [];

    /**
     * @param array $attributes
     */
    public function __construct($attributes)
    {
        $this->import($attributes);
    }

    /**
     * @param $attributes
     */
    public function import($attributes)
    {
        $this->attributes = $attributes;
    }

    /**
     * Returns data from entity
     * @return array
     */
    public function export()
    {
        return $this->attributes;
    }

    /**
     * @param $name
     * @return mixed
     */
    public function __get($name)
    {
        return (isset($this->attributes[$name])) ? $this->attributes[$name] : null;
    }

    /**
     * @param $name
     * @param $value
     */
    public function __set($name, $value)
    {
        $this->attributes[$name] = $value;
    }
}

class Book extends Entity
{

}

/**
 * Usage
 */
$booksMapper = new BooksMapper(new PDO('mysql:hostname=localhost;dbname=test', 'root', ''));
$book = BooksMapper::createEntity([
    'title' => 'Test book',
    'description' => 'Test book',
    'author_id' => 15,
    'status' => 2,
    'date' => time()
]);
$booksMapper->insert($book);

$book->title = 'New title';
$booksMapper->update($book);