Single Table Inheritance in Laravel 4 / Illuminate

Builder.php

<?php namespace App;

use Illuminate\Database\Eloquent\Builder as BaseBuilder;

class Builder extends BaseBuilder{

	/**
	 * Override getModels so it send attributes to the newInstance methods (in newExisting)
	 */
	public function getModels($columns = array('*'))
	{
		// First, we will simply get the raw results from the query builders which we
		// can use to populate an array with Eloquent models. We will pass columns
		// that should be selected as well, which are typically just everything.
		$results = $this->query->get($columns);

		$connection = $this->model->getConnectionName();

		$models = array();

		// Once we have the results, we can spin through them and instantiate a fresh
		// model instance for each records we retrieved from the database. We will
		// also set the proper connection name for the model after we create it.
		foreach ($results as $result)
		{
			$models[] = $model = $this->model->newExisting((array) $result);
			
			$model->setConnection($connection);
		}

		return $models;
	}

}

create_products_table.php

<?php
// migration file

use Illuminate\Database\Migrations\Migration;

class CreateProductsTable extends Migration {

	/**
	 * Run the migrations.
	 *
	 * @return void
	 */
	public function up()
	{
		Schema::create('products', function($table)
		{
			$table->increments('id');
			$table->string('title');
			$table->string('product_type');
			$table->timestamps();
			$table->index('product_type');
		});
	}

	/**
	 * Reverse the migrations.
	 *
	 * @return void
	 */
	public function down()
	{
		Schema::drop('products');
	}

}

Merchandise.php

<?php namespace App;

use App\Product as BaseProduct;

class Merchandise extends BaseProduct {

}

Product.php

<?php namespace App;

use Illuminate\Database\Eloquent\Model;
use App\Builder;

class Product extends Model {

	protected $table = 'products';

	protected $classField = 'product_type';

	public function __construct(array $attributes = array())
	{
		parent::__construct($attributes);
		$this->{$this->classField} = get_class($this);
	}

	public function newInstance($attributes = array(), $exists = false)
	{
		if($this->classField && isset($attributes[$this->classField])){
			$classname = $attributes[$this->classField];
			$model = new $classname;
		}else{
			// May never be use / should not be use in this case, as it should never create a Product!
			$model = new static;
		}
		
		/**
		 * Changed this part, so it use fill or setAttributes, if it come from an existing class or not, not directly via construct (which use fill)
		 */
		if($exists){
			$model->setAttributes($attributes);
		}else{
			$model->fill($attributes);
		}
		$model->exists = $exists;
		return $model;
	}

	/**
	 * Override newQuery to use own Builder and add where automaticaly if not base class
	 */
	public function newQuery()
	{
		$builder = new Builder($this->newBaseQueryBuilder());
		$builder->setModel($this);

		if($this->classField && get_class(new static) !== get_class(new self)){
			$builder->where($this->classField, get_class($this));
		}
		return $builder;
	}
}

products.php

<?php

// seed file

return array(
	array(
		'title'        => 'Book 1',
		'product_type' => 'Brainr\Model\Publication',
		'created_at'   => new DateTime,
		'updated_at'   => new DateTime,
	),
	array(
		'title'        => 'Magazine 2',
		'product_type' => 'Brainr\Model\Publication',
		'created_at'   => new DateTime,
		'updated_at'   => new DateTime,
	),
	array(
		'title'        => 'Table 1',
		'product_type' => 'Brainr\Model\Merchandise',
		'created_at'   => new DateTime,
		'updated_at'   => new DateTime,
	),
	array(
		'title'        => 'Chair 1',
		'product_type' => 'Brainr\Model\Merchandise',
		'created_at'   => new DateTime,
		'updated_at'   => new DateTime,
	),

Publication.php

<?php namespace App;

use App\Product as BaseProduct;

class Publication extends BaseProduct {

}

i've made a package for laravel 4+ to handle that: https://github.com/intrip/laravel-single-table-inheritance