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| 1 | +Camelot Doctrine Inheritance Mapping |
| 2 | +==================================== |
| 3 | + |
| 4 | +Installation |
| 5 | +------------ |
| 6 | + |
| 7 | +Open a command console, enter your project directory and execute: |
| 8 | + |
| 9 | +```console |
| 10 | +$ composer require camelot/doctrine-inheritance-mapping |
| 11 | +``` |
| 12 | + |
| 13 | +This command requires you to have Composer installed globally, as explained |
| 14 | +in the [installation chapter](https://getcomposer.org/doc/00-intro.md) |
| 15 | +of the Composer documentation. |
| 16 | + |
| 17 | +### Standalone Configuration |
| 18 | + |
| 19 | +```php |
| 20 | +use Camelot\DoctrineInheritanceMapping\Annotation\DiscriminatorMapLoader; |
| 21 | +use Doctrine\Common\Annotations\AnnotationReader; |
| 22 | +use Doctrine\Common\Annotations\DocParser; |
| 23 | +use Doctrine\ORM\Configuration; |
| 24 | +use Doctrine\ORM\Mapping\ClassMetadata; |
| 25 | +use Doctrine\ORM\Mapping\Driver\AnnotationDriver; |
| 26 | + |
| 27 | +// Annotation reader & driver |
| 28 | +$reader = new AnnotationReader(new DocParser()); |
| 29 | +$driver = new AnnotationDriver($reader); |
| 30 | +$driver->addPaths(['/path/to/entities']); |
| 31 | + |
| 32 | +// Doctrine configuration |
| 33 | +$config = new Configuration(); |
| 34 | +$config->setMetadataDriverImpl($driver); |
| 35 | + |
| 36 | +$classMetadata = new ClassMetadata(YourEntityName::class); |
| 37 | + |
| 38 | +$loader = new DiscriminatorMapLoader($reader, $config); |
| 39 | +$loader->loadClassMetadata($classMetadata); |
| 40 | +``` |
| 41 | + |
| 42 | +### Framework Configuration |
| 43 | + |
| 44 | +#### Symfony Bundle |
| 45 | + |
| 46 | +If using the Symfony Framework, you can enable the bundle by adding it to the |
| 47 | +list of registered bundles in the `config/bundles.php` file of your project: |
| 48 | + |
| 49 | +```php |
| 50 | +// config/bundles.php |
| 51 | + |
| 52 | +return [ |
| 53 | + // ... |
| 54 | + Camelot\DoctrineInheritanceMapping\Bridge\Symfony\DoctrineInheritanceMappingBundle::class => ['all' => true], |
| 55 | +]; |
| 56 | +``` |
| 57 | + |
| 58 | +Usage |
| 59 | +----- |
| 60 | + |
| 61 | +### Single Table Inheritance |
| 62 | + |
| 63 | +#### `@DiscriminatorMapItem` Annotation |
| 64 | + |
| 65 | +Doctrine's [Single Table Inheritance][single-table-inheritance] is an |
| 66 | +inheritance mapping strategy where all classes of a hierarchy are mapped to a |
| 67 | +single database table. |
| 68 | + |
| 69 | +The mapping is handled by a "discriminator" column, defined in the mapping |
| 70 | +definition of the parent class. This column value defines the entity class to |
| 71 | +use, based on the inheritance hierarchy. This binds the parent to the children |
| 72 | +and mixes responsibilities in the process. |
| 73 | + |
| 74 | +To separate these concerns, this library provides the `@DiscriminatorMapItem` |
| 75 | +annotation for use in *each* entity in a hierarchy, replacing the parent class |
| 76 | +use of Doctrine's `@DiscriminatorMap`, thus eliminating the need to update the |
| 77 | +parent for each subclass. |
| 78 | + |
| 79 | +##### Example |
| 80 | + |
| 81 | +###### Parent Class |
| 82 | + |
| 83 | +```php |
| 84 | +use Camelot\DoctrineInheritanceMapping\Annotation\DiscriminatorEntry; |
| 85 | +use Doctrine\ORM\Mapping as ORM; |
| 86 | + |
| 87 | +/** |
| 88 | + * @ORM\Entity() |
| 89 | + * @ORM\InheritanceType("SINGLE_TABLE") |
| 90 | + * @DiscriminatorMapItem(value="SingleTable") |
| 91 | + */ |
| 92 | +class SingleTable |
| 93 | +{ |
| 94 | + // ... |
| 95 | +} |
| 96 | + |
| 97 | +``` |
| 98 | + |
| 99 | +**NOTE:** Using `@DiscriminatorColumn` along with `@DiscriminatorMapItem` is |
| 100 | +optional, and has been omitted above for clarity. |
| 101 | + |
| 102 | +###### Child(ren) Class |
| 103 | + |
| 104 | +```php |
| 105 | +use Camelot\DoctrineInheritanceMapping\Annotation\DiscriminatorEntry; |
| 106 | +use Doctrine\ORM\Mapping as ORM; |
| 107 | + |
| 108 | +/** |
| 109 | + * @ORM\Entity() |
| 110 | + * @DiscriminatorMapItem(value="SingleTableChild") |
| 111 | + */ |
| 112 | +class SingleTableChild extends SingleTable |
| 113 | +{ |
| 114 | + // ... |
| 115 | +} |
| 116 | +``` |
| 117 | +[single-table-inheritance]: https://www.doctrine-project.org/projects/doctrine-orm/en/2.6/reference/inheritance-mapping.html#single-table-inheritance |
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