Camelot Doctrine Inheritance Mapping

NOTE: For legacy PHP support (7.1+) please use the 1.0 branch.

Installation

Open a command console, enter your project directory and execute:

$ composer require camelot/doctrine-inheritance-mapping

This command requires you to have Composer installed globally, as explained in the installation chapter of the Composer documentation.

Standalone Configuration

use Camelot\DoctrineInheritanceMapping\Annotation\DiscriminatorMapLoader;
use Doctrine\Common\Annotations\AnnotationReader;
use Doctrine\Common\Annotations\DocParser;
use Doctrine\ORM\Configuration;
use Doctrine\ORM\Mapping\ClassMetadata;
use Doctrine\ORM\Mapping\Driver\AnnotationDriver;

// Annotation reader & driver
$reader = new AnnotationReader(new DocParser());
$driver = new AnnotationDriver($reader);
$driver->addPaths(['/path/to/entities']);

// Doctrine configuration
$config = new Configuration();
$config->setMetadataDriverImpl($driver);

$classMetadata = new ClassMetadata(YourEntityName::class);

$loader = new DiscriminatorMapLoader($reader, $config);
$loader->loadClassMetadata($classMetadata);

Framework Configuration

Symfony Bundle

If using the Symfony Framework, you can enable the bundle by adding it to the list of registered bundles in the config/bundles.php file of your project:

// config/bundles.php

return [
    // ...
    Camelot\DoctrineInheritanceMapping\Bridge\Symfony\DoctrineInheritanceMappingBundle::class => ['all' => true],
];

Usage

Single Table Inheritance

@DiscriminatorMapItem Annotation

Doctrine's Single Table Inheritance is an inheritance mapping strategy where all classes of a hierarchy are mapped to a single database table.

The mapping is handled by a "discriminator" column, defined in the mapping definition of the parent class. This column value defines the entity class to use, based on the inheritance hierarchy. This binds the parent to the children and mixes responsibilities in the process.

To separate these concerns, this library provides the @DiscriminatorMapItem annotation for use in each entity in a hierarchy, replacing the parent class use of Doctrine's @DiscriminatorMap, thus eliminating the need to update the parent for each subclass.

Example

Parent Class

<?php
namespace App\Entity;

use Camelot\DoctrineInheritanceMapping\Annotation\DiscriminatorMapItem;
use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity()
 * @ORM\InheritanceType("SINGLE_TABLE")
 * @DiscriminatorMapItem(value="SingleTable")
 */
class SingleTable
{
    // ...
}

NOTE: Using @DiscriminatorColumn along with @DiscriminatorMapItem is optional, and has been omitted above for clarity.

Child(ren) Class

<?php
namespace App\Entity;

use Camelot\DoctrineInheritanceMapping\Annotation\DiscriminatorMapItem;
use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity()
 * @DiscriminatorMapItem(value="SingleTableChild")
 */
class SingleTableChild extends SingleTable
{
    // ...
}