Register custom Doctrine type in Symfony 4.x

Create new custom Doctrine type class: app\src\Doctrine\DBAL\Types\Tinyint.php

namespace App\Doctrine\DBAL\Types;

use Doctrine\DBAL\Types\Type;
use Doctrine\DBAL\Platforms\AbstractPlatform;

class Tinyint extends Type
{
    const TINYINT = 'tinyint';

    public function getSQLDeclaration(array $fieldDeclaration, AbstractPlatform $platform)
    {
        $fieldDeclaration = array_merge([
            'length' => 1,
        ], $fieldDeclaration);

        return sprintf("TINYINT(%d)",
                $fieldDeclaration['length']
            );
    }

    public function convertToPHPValue($value, AbstractPlatform $platform)
    {
        return (int) $value;
    }

    public function convertToDatabaseValue($value, AbstractPlatform $platform)
    {
        return (int) $value;
    }

    public function getName()
    {
        return self::TINYINT;
    }

    public function getBindingType()
    {
        return \PDO::PARAM_INT;
    }
}

Add define config: config/packages/doctrine.yml

doctrine:
    dbal:
        types:
            tinyint: App\Doctrine\DBAL\Types\Tinyint

In entity class: app\src\Entity\User.php

    /**
     * @ORM\Column(name="DEL_F", type="tinyint", options={"default" = 0}, length=1)
     */
    private $del_f;