Symfony 5.4 problem with using Unique and Hostname together - symfony

Question

I am trying to use Unique and Hostname constraint together in Syfony 5.4 entity. Lets have:
/**
* #ORM\Column(name="domain", type="string", length=150, nullable=false, unique=true)
* #Assert\NotBlank()
* #Assert\Hostname()
*/
private $domain;
This validate without problems. But when I add Unique constraint, it fails with message - This value should be of type array|IteratorAggregate.
/**
* #ORM\Column(name="domain", type="string", length=150, nullable=false, unique=true)
* #Assert\NotBlank()
* #Assert\Unique()
* #Assert\Hostname()
*/
private $domain;
I need both validation, yes, in this case it fails on database INSERT, but I want to validate form. How is correct way?
Thank you
DR

Answer 1

If I understand correctly you want to validate that the domain (or hostname) is unique inside the database table. In that case, you would have to use UniqueEntity see https://symfony.com/doc/current/reference/constraints/UniqueEntity.html.
It is worth mentioning that this doesn't protect you against race conditions.
<?php
namespace App\Entity;
use Doctrine\ORM\Mapping as ORM;
use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity;
use Symfony\Component\Validator\Constraints as Assert;
/**
* #ORM\Entity
* #UniqueEntity("domain")
*/
class YourEntity
{
/**
* #ORM\Column(name="domain", type="string", length=150, nullable=false, unique=true)
* #Assert\NotBlank()
* #Assert\Hostname()
*/
protected $domain;
}