PHP - Prevent Null In One-to-one Doctrine Relationship

I think I am close, but not sure if I am quite there.  Am I doing this correctly?

I have several entity classes which will use class type inheritance:

MyNamespace\MyApp\Vehicle\Vehicle
    MyNamespace\MyApp\Vehicle\AirVehicle\AirVehicle
        MyNamespace\MyApp\Vehicle\AirVehicle\Airplane\Airplane
        MyNamespace\MyApp\Vehicle\AirVehicle\Rocket\Rocket
    MyNamespace\MyApp\Vehicle\GroundVehicle\GroundVehicle
        MyNamespace\MyApp\Vehicle\GroundVehicle\Car\Car
        MyNamespace\MyApp\Vehicle\GroundVehicle\Train\Train
                
The entity meta data is as follows:

#MyNamespace.MyApp.Vehicle.Vehicle.dcm.yml
MyNamespace\MyApp\Vehicle\Vehicle:
    type: entity
    table: vehicle_table
    inheritanceType: JOINED
    discriminatorColumn:
        name: discriminator_column
        type: string
    discriminatorMap:
        vehicle: Vehicle
        groundVehicle: MyNamespace\MyApp\Vehicle\GroundVehicle\GroundVehicle
        airVehicle: MyNamespace\MyApp\Vehicle\AirVehicle\AirVehicle
    repositoryClass: Vehicle
    id:
        id:
            type: integer
            generator:
                strategy: AUTO
    fields:
        grandParentItem1:
            type: string
        grandParentItem2:
            type: string

#MyNamespace.MyApp.Vehicle.AirVehicle.AirVehicle.dcm.yml
MyNamespace\MyApp\Vehicle\AirVehicle\AirVehicle:
    type: entity
    table: air_vehicle
    extends: MyNamespace\MyApp\Vehicle\Vehicle
    inheritanceType: JOINED
    discriminatorMap:
        airVehicle: AirVehicle
        airplane: MyNamespace\MyApp\Vehicle\AirVehicle\Airplane\Airplane
        rocket: MyNamespace\MyApp\Vehicle\AirVehicle\Rocket\Rocket
    repositoryClass: AirVehicle
    id:
        id:
            associationKey: true
    fields:
        parentItem1:
            type: string
        parentItem2:
            type: string

#MyNamespace.MyApp.Vehicle.AirVehicle.Rocket.Rocket.dcm.yml
MyNamespace\MyApp\Vehicle\AirVehicle\Rocket\Rocket:
    extends: MyNamespace\MyApp\Vehicle\AirVehicle\AirVehicle
    type: entity
    table: rocket_table
    id:
        id:
            associationKey: true
    repositoryClass: Rocket
    fields:
        childItem1:
            type: string
        childItem2:
            type: string

I haven't shown GroundVehicle or Train, Car, and Airplane, but they are almost identical to AirVehicle and Rocket, respectively.

I've discovered that the barebone entities need to be manually created prior to using orm:generate-entities else I get class not found errors, and have created them as shown below.
        
inheritance_src/MyNamespace/MyApp/Vehicle/Vehicle.php
    inheritance_src/MyNamespace/MyApp/Vehicle/AirVehicle/AirVehicle.php
        inheritance_src/MyNamespace/MyApp/Vehicle/AirVehicle/Airplane/Airplane.php
        inheritance_src/MyNamespace/MyApp/Vehicle/AirVehicle/Rocket/Rocket.php
    inheritance_src/MyNamespace/MyApp/Vehicle/GroundVehicle/GroundVehicle.php
        inheritance_src/MyNamespace/MyApp/Vehicle/GroundVehicle/Car/Car.php
        inheritance_src/MyNamespace/MyApp/Vehicle/GroundVehicle/Train/Train.php

[michael@devserver doctrine]$ find inheritance_src -name "*.php" -exec cat {} \;
<?php
namespace MyNamespace\MyApp\Vehicle\AirVehicle\Airplane;
class Airplane extends \MyNamespace\MyApp\Vehicle\AirVehicle\AirVehicle{}
<?php
namespace MyNamespace\MyApp\Vehicle\AirVehicle\Rocket;
class Rocket extends \MyNamespace\MyApp\Vehicle\AirVehicle\AirVehicle{}
<?php
namespace MyNamespace\MyApp\Vehicle\AirVehicle;
abstract class AirVehicle extends \MyNamespace\MyApp\Vehicle\Vehicle{}
<?php
namespace MyNamespace\MyApp\Vehicle\GroundVehicle\Car;
class Car extends \MyNamespace\MyApp\Vehicle\GroundVehicle\GroundVehicle{}
<?php
namespace MyNamespace\MyApp\Vehicle\GroundVehicle\Train;
class Train extends \MyNamespace\MyApp\Vehicle\GroundVehicle\GroundVehicle{}
<?php
namespace MyNamespace\MyApp\Vehicle\GroundVehicle;
abstract class GroundVehicle extends \MyNamespace\MyApp\Vehicle\Vehicle{}
<?php
namespace MyNamespace\MyApp\Vehicle;
abstract class Vehicle{}

I then am able to successfully create the entities using orm:generate-entities, schema using orm:schema-tool:create, and repositories using orm:generate-repositories.

Does everything seem correct?

A couple of issues which I have my doubts:

Thank you
 

Hoping to get some thoughts on how Doctrine array collections should be used when the position of the items in the collection must be controlled.

For instance, I have a Chart object which has various primitive properties as well as a series property which is an array collection.  Each member in the series collection is a Serie object which has various primitive properties as well as a data property which is an array collection.  Each member in the data collection is a Datum object which includes various primitive properties.  The following just refers to the series collection, however, will be doing the same with the data collection.

Chart will have methods to add a Serie to the end of the series collection, modify a Serie for a given position, delete a Serie for a given position, swap the position of two Serie, and retrieve all Serie(s) in their designated position order. 

To implement this, my thought is to include a integer position property in Serie, and when retrieving the results will just ORDER BY this column if using DQL or maybe will use Criteria to filter the results.  I am not, however, sure how to implement some of the other methods.

When adding a new Serie to the end of the collection, should I do something like:

class Chart
{
    public function addSerie(array $params):Chart {
        $serie=new Serie();
        $serie->setName($params['name']);
        $position=$this->series->count();
        $serie->setPosition($position);
        $this->addSeries($serie);
    }
}

Also, ArrayCollection has various methods such as offsetGet(), but how does the collection know what to be ordered by?  Maybe using something like the following? 

class Chart
{
    public function __construct() {
        $this->series->getIterator()->uasort(function ($first, $second) {
            return (int) $first->getPosition() > (int) $second->getPosition() ? 1 : -1;
        });
    }
}

    
Also, any general thoughts on this topic would be appreciated.

PS.  Originally, I was using the name "Series" instead of "Serie", but the lack of separate forms for singular and plural was messing with me.  Was thinking of using SeriesNode instead, but didn't want to need to follow this same naming convention for other items...

I am trying to class type inheritance with Doctrine.  Eventually, I will be defining things using XML, but all the examples are done using doctags.  I found the following and it seems to work.

<?php
use Doctrine\ORM\Mapping as ORM;

/**
 * Inventory entity
 *
 * @ORM\Entity(repositoryClass="Inventory")
 * @ORM\Table(name="inventory")
 * @ORM\InheritanceType("JOINED")
 * @ORM\DiscriminatorColumn(name="discriminator_column", type="string")
 * @ORM\DiscriminatorMap({"inventory" = "AbstractItem", "inventory_room" = "Room"})
 */
abstract class AbstractItem
{
    /**
     * @ORM\Id @ORM\Column(name="inventory_id") @ORM\GeneratedValue
     * @var int
     */
    protected $inventory_id;

    /**
     * @ORM\Column(type="string")
     * @var string
     */
    protected $category;

    /**
     * @ORM\Column(type="string")
     * @var string
     */
    protected $part_number;
 }


use Doctrine\ORM\Mapping as ORM;

/**
 * Inventory Room entity
 * @ORM\Entity
 * @ORM\Table(name="inventory_room")
 */
class Room extends AbstractItem
{
    /**
     * @ORM\Column(type="string")
     * @var string
     */
    protected $room_type;

    /**
     * @ORM\Column(type="string")
     * @var string
     */
    protected $rack_limit;

But then I convert it to XML or YAML, and I get a Entity class 'Room' used in the discriminator map of class 'AbstractItem' does not exist error when trying to build the classes.  I've also tried changing the type to mappedSuperclass, but no success.

Any ideas?

Also, what is the purpose of the DiscriminatorColumn?

Thanks

AbstractItem:
    type: entity
    table: inventory
    inheritanceType: JOINED
    discriminatorColumn:
        name: discriminator_column
        type: string
    discriminatorMap:
        inventory: AbstractItem
        inventory_room: Room
    repositoryClass: Inventory
    id:
        inventory_id:
            type: string
    fields:
        category:
            type: string
        part_number:
            type: string


Room:
    type: entity
    table: inventory_room
    fields:
        room_type:
            type: string
        rack_limit:
            type: string

<?xml version="1.0" encoding="utf-8"?>
<doctrine-mapping xmlns="http://doctrine-project.org/schemas/orm/doctrine-mapping" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://doctrine-project.org/schemas/orm/doctrine-mapping https://www.doctrine-project.org/schemas/orm/doctrine-mapping.xsd">
  <entity repository-class="Inventory" name="AbstractItem" table="inventory" inheritance-type="JOINED">
    <discriminator-column name="discriminator_column" type="string" length="255"/>
    <discriminator-map>
      <discriminator-mapping value="inventory" class="AbstractItem"/>
      <discriminator-mapping value="inventory_room" class="Room"/>
    </discriminator-map>
    <id name="inventory_id" type="string" column="inventory_id">
      <generator strategy="IDENTITY"/>
    </id>
    <field name="category" type="string" column="category" precision="0" scale="0" nullable="false"/>
    <field name="part_number" type="string" column="part_number" precision="0" scale="0" nullable="false"/>
  </entity>
</doctrine-mapping>


<?xml version="1.0" encoding="utf-8"?>
<doctrine-mapping xmlns="http://doctrine-project.org/schemas/orm/doctrine-mapping" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://doctrine-project.org/schemas/orm/doctrine-mapping https://www.doctrine-project.org/schemas/orm/doctrine-mapping.xsd">
  <entity name="Room" table="inventory_room">
    <id name="inventory_id" type="string" column="inventory_id">
      <generator strategy="IDENTITY"/>
    </id>
    <field name="room_type" type="string" column="room_type" precision="0" scale="0" nullable="false"/>
    <field name="rack_limit" type="string" column="rack_limit" precision="0" scale="0" nullable="false"/>
    <field name="category" type="string" column="category" precision="0" scale="0" nullable="false"/>
    <field name="part_number" type="string" column="part_number" precision="0" scale="0" nullable="false"/>
  </entity>
</doctrine-mapping>

/root
  |-- /Src
        |-- /App
              |-- /Model
                    |-- ** (Application Entities) **
        |-- /Core
              |-- /Model
                    |-- ** (Core Entities) **

$config = Setup::createAnnotationMetadataConfiguration(array(__DIR__. "/src"), $isDevMode);

Trying to create a model where Parent1 and Parent2 extend Grandparent, and Child1_1 and Child1_2 extend Parent1 as well as Child2_1 and Child2_2 extend Parent2.

I set up my definitions:

Grandparent:
    type: entity
    table: grandparent_table
    inheritanceType: JOINED
    discriminatorColumn:
        name: discriminator_column_grandparent
        type: string
    repositoryClass: GrandParent
    id:
        id:
            type: integer
            generator:
                strategy: AUTO
    fields:
        GrandParent_Item1:
            type: string
        GrandParent_Item2:
            type: string
Parent1:
    type: entity
    table: parent_table1
    extends: Grandparent
    inheritanceType: JOINED
    discriminatorColumn:
        name: discriminator_column_parent1
        type: string
    id:
        id:
            associationKey: true
    fields:
        Parent1_Item1:
            type: string
        Parent1_Item2:
            type: string
Parent2:
    type: entity
    table: parent_table2
    extends: Grandparent
    inheritanceType: JOINED
    discriminatorColumn:
        name: discriminator_column_parent2
        type: string
    id:
        id:
            associationKey: true
    fields:
        Parent2_Item1:
            type: string
        Parent2_Item2:
            type: string
Child1_1:
    extends: Parent1
    type: entity
    table: child1_1_table
    id:
        id:
            associationKey: true
    fields:
        Child1_1_Item1:
            type: string
        Child1_1_Item2:
            type: string
Child1_2:
    extends: Parent1
    type: entity
    table: child1_2_table
    id:
        id:
            associationKey: true
    fields:
        Child1_2_Item1:
            type: string
        Child1_2_Item2:
            type: string
Child2_1:
    extends: Parent2
    type: entity
    table: child2_1_table
    id:
        id:
            associationKey: true
    fields:
        Child2_1_Item1:
            type: string
        Child2_1_Item2:
            type: string
Child2_2:
    extends: Parent2
    type: entity
    table: child2_2_table
    id:
        id:
            associationKey: true
    fields:
        Child2_2_Item1:
            type: string
        Child2_2_Item2:
            type: string

 And then generate my entities:       

$ vendor/bin/doctrine orm:generate-entities -vvv src

 Processing entity "Child1_1"
 Processing entity "Child1_2"
 Processing entity "Child2_1"
 Processing entity "Child2_2"
 Processing entity "Grandparent"
 Processing entity "Parent1"
 Processing entity "Parent2"


 [OK] Entity classes generated to "/var/www/doctrine/src"

Note that I needed to manually edit the Parent1 and 2 classes to extend Grandparent as well as the individual Child classes to extend their applicable Parent.

Next, I create the schema:

$ vendor/bin/doctrine orm:schema-tool:create --dump-sql

 The following SQL statements will be executed:

     CREATE TABLE child1_1_table (id INT NOT NULL, Child1_1_Item1 VARCHAR(255) NOT NULL, Child1_1_Item2 VARCHAR(255) NOT NULL, PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE = InnoDB;
     CREATE TABLE child1_2_table (id INT NOT NULL, Child1_2_Item1 VARCHAR(255) NOT NULL, Child1_2_Item2 VARCHAR(255) NOT NULL, PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE = InnoDB;
     CREATE TABLE child2_1_table (id INT NOT NULL, Child2_1_Item1 VARCHAR(255) NOT NULL, Child2_1_Item2 VARCHAR(255) NOT NULL, PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE = InnoDB;
     CREATE TABLE child2_2_table (id INT NOT NULL, Child2_2_Item1 VARCHAR(255) NOT NULL, Child2_2_Item2 VARCHAR(255) NOT NULL, PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE = InnoDB;
     CREATE TABLE grandparent_table (id INT AUTO_INCREMENT NOT NULL, GrandParent_Item1 VARCHAR(255) NOT NULL, GrandParent_Item2 VARCHAR(255) NOT NULL, discriminator_column_grandparent VARCHAR(255) NOT NULL, PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE = InnoDB;
     CREATE TABLE parent_table1 (id INT NOT NULL, Parent1_Item1 VARCHAR(255) NOT NULL, Parent1_Item2 VARCHAR(255) NOT NULL, PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE = InnoDB;
     CREATE TABLE parent_table2 (id INT NOT NULL, Parent2_Item1 VARCHAR(255) NOT NULL, Parent2_Item2 VARCHAR(255) NOT NULL, PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE = InnoDB;
     ALTER TABLE child1_1_table ADD CONSTRAINT FK_3445750EBF396750 FOREIGN KEY (id) REFERENCES grandparent_table (id) ON DELETE CASCADE;
     ALTER TABLE child1_2_table ADD CONSTRAINT FK_5AD6F93BF396750 FOREIGN KEY (id) REFERENCES grandparent_table (id) ON DELETE CASCADE;
     ALTER TABLE child2_1_table ADD CONSTRAINT FK_DC849CBBF396750 FOREIGN KEY (id) REFERENCES grandparent_table (id) ON DELETE CASCADE;
     ALTER TABLE child2_2_table ADD CONSTRAINT FK_3C205356BF396750 FOREIGN KEY (id) REFERENCES grandparent_table (id) ON DELETE CASCADE;
     ALTER TABLE parent_table1 ADD CONSTRAINT FK_5386E15BBF396750 FOREIGN KEY (id) REFERENCES grandparent_table (id) ON DELETE CASCADE;
     ALTER TABLE parent_table2 ADD CONSTRAINT FK_CA8FB0E1BF396750 FOREIGN KEY (id) REFERENCES grandparent_table (id) ON DELETE CASCADE;

I see how Grandparent has discriminatorColumn discriminator_column_grandparent as expected.

But why doesn't Parent1 and Parent2 have discriminatorColumn's discriminator_column_parent1 and discriminator_column_parent2?

Note that I've also tried making Grandparent, Parent1, and Parent2 abstract but get the same results.  I've also messed around with Mapped Superclasses, but I don't think they are applicable for my use (correct me if you think I am wrong).

Thanks!

Finally getting around to giving Doctrine a try.  Looks like YAML is depreciated, so my choices are DocBlocks or XML.

I am sure it is personal choice, however, I would like to start off with what most feel is the best path.

Any recommendations?  Thanks

I am doing something stupid, and just can't see it and hoping someone has better eyes than mine.  I have two Doctrine entities which extend another class using single class inheritance, but when retrieving the collection of either of the two child classes, I get the collection of the parent (i.e. combination of both child classes).  I've experimented with making the parent abstract and not including it in the discriminator map but no change.  In hopes to identifying my mistake, I created a new Symfony project with just the relevant classes and show all steps below.

Initial install by running the following:

symfony new test
composer update
composer require doctrine/orm
composer require migrations
composer require maker --dev
composer require security

Using "php bin/console make:user", I created three users: AbstractUser, OwnerUser, VendorUser.  I then edited all three entities and the owner and vendor repositories as follows:

<?php

namespace App\Entity;

use App\Repository\AbstractUserRepository;
use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\Security\Core\User\UserInterface;

/**
 * @ORM\Entity(repositoryClass=AbstractUserRepository::class)
 * @ORM\InheritanceType("SINGLE_TABLE")
 * @ORM\DiscriminatorColumn(name="discr", type="string")
 * @ORM\DiscriminatorMap({"owner" = "OwnerUser", "vendor" = "VendorUser", "abstract" = "AbstractUser"})
 */
class AbstractUser implements UserInterface
{
    // No changes made
}

<?php

namespace App\Entity;

use App\Repository\OwnerUserRepository;
use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity(repositoryClass=OwnerUserRepository::class)
 */
class OwnerUser extends AbstractUser
{
}

<?php

namespace App\Entity;

use App\Repository\VendorUserRepository;
use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity(repositoryClass=VendorUserRepository::class)
 */
class VendorUser extends AbstractUser
{
}

No change to AbstractUserRepository.

<?php

namespace App\Repository;

class OwnerUserRepository extends AbstractUserRepository
{
}

<?php

namespace App\Repository;

class VendorUserRepository extends AbstractUserRepository
{
}

Then I migrated the DB.

php bin/console doctrine:schema:drop --full-database --force
rm migrations/*
php bin/console make:migration
php bin/console doctrine:migrations:migrate

Next I created two OwnerUsers and one VendorUser using a command script I wrote shown at the end of this post.

# php bin/console app:tester create OwnerUser roles=[]
# php bin/console app:tester create OwnerUser roles=[]
# php bin/console app:tester create VendorUser roles=[]

Checked the PostSQL database.

facdocs=> \d
                     List of relations
 Schema |            Name             |   Type   |  Owner
--------+-----------------------------+----------+---------
 public | abstract_user               | table    | facdocs
 public | abstract_user_id_seq        | sequence | facdocs
 public | doctrine_migration_versions | table    | facdocs
(3 rows)

facdocs=> select * from abstract_user;
 id |    email    | roles |    password    | discr
----+-------------+-------+----------------+--------
  1 | setEmail158 | []    | setPassword146 | owner
  2 | setEmail87  | []    | setPassword101 | owner
  3 | setEmail62  | []    | setPassword20  | vendor
(3 rows)

facdocs=>

Next, I retrieved the entities using Doctrine along with the beforementioned test script.
 

[michael@devserver test]$ php bin/console app:tester read VendorUser
Test Entity Manager
============

command: read
entity: VendorUser
class: \App\Entity\VendorUser
properties: []
array(3) {
  [0]=>
  object(stdClass)#293 (5) {
    ["__CLASS__"]=>
    string(20) "App\Entity\OwnerUser"
    ["id:App\Entity\AbstractUser:private"]=>
    int(1)
    ["email:App\Entity\AbstractUser:private"]=>
    string(11) "setEmail158"
    ["roles:App\Entity\AbstractUser:private"]=>
    string(8) "Array(0)"
    ["password:App\Entity\AbstractUser:private"]=>
    string(14) "setPassword146"
  }
  [1]=>
  object(stdClass)#294 (5) {
    ["__CLASS__"]=>
    string(20) "App\Entity\OwnerUser"
    ["id:App\Entity\AbstractUser:private"]=>
    int(2)
    ["email:App\Entity\AbstractUser:private"]=>
    string(10) "setEmail87"
    ["roles:App\Entity\AbstractUser:private"]=>
    string(8) "Array(0)"
    ["password:App\Entity\AbstractUser:private"]=>
    string(14) "setPassword101"
  }
  [2]=>
  object(stdClass)#358 (5) {
    ["__CLASS__"]=>
    string(21) "App\Entity\VendorUser"
    ["id:App\Entity\AbstractUser:private"]=>
    int(3)
    ["email:App\Entity\AbstractUser:private"]=>
    string(10) "setEmail62"
    ["roles:App\Entity\AbstractUser:private"]=>
    string(8) "Array(0)"
    ["password:App\Entity\AbstractUser:private"]=>
    string(13) "setPassword20"
  }
}
[michael@devserver test]$
[michael@devserver test]$ php bin/console app:tester read OwnerUser
Test Entity Manager
============

command: read
entity: OwnerUser
class: \App\Entity\OwnerUser
properties: []
array(3) {
  [0]=>
  object(stdClass)#293 (5) {
    ["__CLASS__"]=>
    string(20) "App\Entity\OwnerUser"
    ["id:App\Entity\AbstractUser:private"]=>
    int(1)
    ["email:App\Entity\AbstractUser:private"]=>
    string(11) "setEmail158"
    ["roles:App\Entity\AbstractUser:private"]=>
    string(8) "Array(0)"
    ["password:App\Entity\AbstractUser:private"]=>
    string(14) "setPassword146"
  }
  [1]=>
  object(stdClass)#294 (5) {
    ["__CLASS__"]=>
    string(20) "App\Entity\OwnerUser"
    ["id:App\Entity\AbstractUser:private"]=>
    int(2)
    ["email:App\Entity\AbstractUser:private"]=>
    string(10) "setEmail87"
    ["roles:App\Entity\AbstractUser:private"]=>
    string(8) "Array(0)"
    ["password:App\Entity\AbstractUser:private"]=>
    string(14) "setPassword101"
  }
  [2]=>
  object(stdClass)#358 (5) {
    ["__CLASS__"]=>
    string(21) "App\Entity\VendorUser"
    ["id:App\Entity\AbstractUser:private"]=>
    int(3)
    ["email:App\Entity\AbstractUser:private"]=>
    string(10) "setEmail62"
    ["roles:App\Entity\AbstractUser:private"]=>
    string(8) "Array(0)"
    ["password:App\Entity\AbstractUser:private"]=>
    string(13) "setPassword20"
  }
}
[michael@devserver test]$

As seen, when requesting a collection of either OwnerUsers or VendorUsers, I am retrieving the combination of both collections.  I am sure it is totally user (i.e. me) error, but just don't see it.  Are you able to see my stupid mistake?  Thanks

My test script is below:
 

<?php

namespace App\Command;

use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\Console\Input\InputArgument;
use Doctrine\ORM\EntityManagerInterface;
use Doctrine\Common\Util\Debug;

class Tester extends Command
{
    // the name of the command (the part after "bin/console")
    protected static $defaultName = 'app:tester';
    private $entityManager;
    public function __construct(EntityManagerInterface $entityManager)
    {
        $this->entityManager = $entityManager;
        parent::__construct();
    }

    protected function configure()
    {
        $this
        ->setDescription('Doctrine Object Tester.  --help')
        ->setHelp('This command allows you to query a single entity...')
        ->addArgument('cmd', InputArgument::REQUIRED, 'The command name [create, read].')
        ->addArgument('entity', InputArgument::REQUIRED, 'The name of the entity.')
        ->addArgument('properties', InputArgument::IS_ARRAY | InputArgument::OPTIONAL, 'properies (foo=foo bla=[]')
        ;
    }

    private function getProperties($input)
    {
        $properties=[];
        foreach($input as $property) {
            $property=explode('=', $property);
            $name = trim($property[0]);
            $value = trim($property[1]);
            if($value === '[]') {
                $value = [];
            }
            elseif($value === 'null') {
                $value = null;
            }
            elseif(substr($value, 0, 1) === '/') {
                $value = explode('/', substr($value, 1));
                $class = ucfirst(substr($value[0], 0, -1));
                $class = '\App\Entity\\'.$class;
                if(count($value)===1) {
                    $value = $this->entityManager->getRepository($class)->findAll();
                }
                else {
                    $value = $this->entityManager->getRepository($class)->find($value[1]);
                }
            }
            $properties[$name] = $value;
        }
        return $properties;
    }

    protected function execute(InputInterface $input, OutputInterface $output)
    {
        $output->writeln([
            'Test Entity Manager',
            '============',
            '',
        ]);

        // retrieve the argument value using getArgument()

        $cmd = $input->getArgument('cmd');
        $output->writeln('command: '.$cmd);
        $entity = $input->getArgument('entity');
        $output->writeln('entity: '.$entity);
        $class = '\App\Entity\\'.$entity;
        $output->writeln('class: '.$class);
        $properties = $this->getProperties($input->getArgument('properties'));

        $output->writeln('properties: '.json_encode($properties));

        switch($cmd) {
            case 'create':
                $entity = new $class;
                foreach(get_class_methods($entity) as $method) {
                    if(substr($method, 0, 3)==='set') {
                        $m = lcfirst(substr($method, 3));
                        $entity->$method(array_key_exists($m, $properties)?$properties[$m]:$method.rand(0,200));
                    }
                }
                $this->entityManager->persist($entity);
                $this->entityManager->flush();
                $output->writeln('entity created');
                break;
            case 'read':
                Debug::dump($this->entityManager->getRepository($class)->findAll());
                break;
            default:
                $output->writeln('INVALID COMMAND: '.$cmd.'.  Only create and read are supported.'); 
        }
        return Command::SUCCESS;
    }
}

Anyone know why the following results in an error?  Not a big deal as memory is not an issue and I can (and have) just changed it to create a new array instead of using a generator, but still curious.  Thanks

<?php
foreach($doctrineCollection as $doctrineEntity){
    yield new MyWrapper($doctrineEntity);
    /*
    After around 4 iterations, results in the following error:
    
    syslog
    Apr 06 15:25:25 myserver.net kernel: php-fpm[42889]: segfault at 7f8156a14100 ip 000055bb1d79acfd sp 00007ffd0b50a968 error 4 in php-fpm[55bb1d47c000+46e000]

    /var/log/php-fpm/error.log
    [Mon Apr 06 20:06:38.781360 2020] [proxy_fcgi:error] [pid 1501:tid 140210423629568] (104)Connection reset by peer: [client 12.345.67.890:45574] AH01075: Error dispatching request to :

    /var/log/httpd/error_log
    [06-Apr-2020 20:04:52] WARNING: [pool michael] child 5524 exited on signal 11 (SIGSEGV) after 0.138268 seconds from start
    [06-Apr-2020 20:04:52] NOTICE: [pool michael] child 5526 started
    */
}

class MyWrapper
{
    private $doctrineEntity;

    public function __construct($doctrineEntity)
    {
        $this->doctrineEntity=$doctrineEntity;
    }
}

I am a little confused with the difference between Symfony Events and Event Listners and Doctrine Events.

The Doctrine events look pretty straight forward and are primary used for entity persistence, and I have outlined my understanding below:

I am more confused with the Symfony events and my interpretation as listed below is likely incorrect.

Are they used for totally different purposes or can one use Symfony events to also deal with entities?  Where would one want to use these Symfony events?

Is there a reason why Doctrine Lifecycle Subscribers are located in src/EventListener and not src/EventSubscriber

Are Doctrine Lifecycle and Entity Listeners really only for a single event as I interpret the documentation states, or is it one method per Doctrine event such as the following?

    App\EventListener\SearchIndexer:
        tags:
            -
                name: 'doctrine.event_listener'
                event: 'postPersist'
            -
                name: 'doctrine.event_listener'
                event: 'postUpdate'

Based on the comments on my previous question, took some tutorials on how to avoid injections on query. Does the code below prevents against it in any way.? Secondly, can you recommend a good article that writes well in how to secure input data by users. Please be kind with your comments.😉😉. Thankks in advance.

The code works fine.
 

<?php 

include 'db.php';

error_reporting(E_ALL | E_WARNING | E_NOTICE);

ini_set('display_errors', TRUE);

 if(isset($_POST['submit']))

 {
    
 $username = $_POST['username']; 
$password =  ($_POST['password']); 

$sql = "SELECT * FROM customer WHERE username = ?";
$stmt = $connection->prepare($sql); 
$stmt->bind_param('s', $username);
$stmt->execute();
$result = $stmt->get_result();
$count =  $result->num_rows;
   if($count == 1) 
                         {
while ($row = $result->fetch_assoc())
 {
    if ($row['status'] == 'blocked')

 {

 echo'your account is suspended'


   session_destroy();

   exit();

  }

 else if($row['status'] == 'active')
{

if($username !== $row['username']) 

 { 
echo '<script>swal.fire("ERROR!!", " Username is not correct. Check Again", "error");</script>';
} 
if($password !== $row['password']) 
{
  echo'<script>swal.fire("ERROR!!!", "Your Password is Incorrect. Check Again.", "error");</script>';       
}
if($username == $row['username'] && $password == $row['password']) 
{ 
header('Location:cpanel/');
else
{
}
}//if count
}//while loop
}//submit
?>