Unique.rst

Unique

Validates that all the elements of the given collection are unique (none of them is present more than once). By default elements are compared strictly, so '7' and 7 are considered different elements (a string and an integer, respectively). If you want to apply any other comparison logic, use the normalizer option.

.. seealso::

    If you want to apply different validation constraints to the elements of a
    collection or want to make sure that certain collection keys are present,
    use the :doc:`Collection constraint </reference/constraints/Collection>`.

.. seealso::

    If you want to validate that the value of an entity property is unique among
    all entities of the same type (e.g. the registration email of all users) use
    the :doc:`UniqueEntity constraint </reference/constraints/UniqueEntity>`.

Applies to	:ref:`property or method <validation-property-target>`
Class	:class:`Symfony\\Component\\Validator\\Constraints\\Unique`
Validator	:class:`Symfony\\Component\\Validator\\Constraints\\UniqueValidator`

Basic Usage

This constraint can be applied to any property of type array or \Traversable. In the following example, $contactEmails is an array of strings:

.. configuration-block::

    .. code-block:: php-attributes

        // src/Entity/Person.php
        namespace App\Entity;

        use Symfony\Component\Validator\Constraints as Assert;

        class Person
        {
            #[Assert\Unique]
            protected array $contactEmails;
        }

    .. code-block:: yaml

        # config/validator/validation.yaml
        App\Entity\Person:
            properties:
                contactEmails:
                    - Unique: ~

    .. code-block:: xml

        <!-- config/validator/validation.xml -->
        <?xml version="1.0" encoding="UTF-8" ?>
        <constraint-mapping xmlns="http://symfony.com/schema/dic/constraint-mapping"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://symfony.com/schema/dic/constraint-mapping https://symfony.com/schema/dic/constraint-mapping/constraint-mapping-1.0.xsd">

            <class name="App\Entity\Person">
                <property name="contactEmails">
                    <constraint name="Unique"/>
                </property>
            </class>
        </constraint-mapping>

    .. code-block:: php

        // src/Entity/Person.php
        namespace App\Entity;

        use Symfony\Component\Validator\Constraints as Assert;
        use Symfony\Component\Validator\Mapping\ClassMetadata;

        class Person
        {
            // ...

            public static function loadValidatorMetadata(ClassMetadata $metadata): void
            {
                $metadata->addPropertyConstraint('contactEmails', new Assert\Unique());
            }
        }

Options

fields

type: array | string

This is defines the key or keys in a collection that should be checked for uniqueness. By default, all collection keys are checked for uniqueness.

For instance, assume you have a collection of items that contain a latitude, longitude and label fields. By default, you can have duplicate coordinates as long as the label is different. By setting the fields option, you can force latitude+longitude to be unique in the collection:

.. configuration-block::

// src/Entity/PointOfInterest.php
namespace App\Entity;

use Symfony\Component\Validator\Constraints as Assert;

class PointOfInterest
{
    #[Assert\Unique(fields: ['latitude', 'longitude'])]
    protected array $coordinates;
}

# config/validator/validation.yaml
App\Entity\PointOfInterest:
    properties:
        coordinates:
            - Unique:
                  fields: [latitude, longitude]

<!-- config/validator/validation.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<constraint-mapping xmlns="http://symfony.com/schema/dic/constraint-mapping"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://symfony.com/schema/dic/constraint-mapping https://symfony.com/schema/dic/constraint-mapping/constraint-mapping-1.0.xsd">

    <class name="App\Entity\PointOfInterest">
        <property name="coordinates">
            <constraint name="Unique">
                <option name="fields">
                    <value>latitude</value>
                    <value>longitude</value>
                </option>
            </constraint>
        </property>
    </class>
</constraint-mapping>

// src/Entity/PointOfInterest.php
namespace App\Entity;

use Symfony\Component\Validator\Constraints as Assert;
use Symfony\Component\Validator\Mapping\ClassMetadata;

class PointOfInterest
{
    // ...

    public static function loadValidatorMetadata(ClassMetadata $metadata): void
    {
        $metadata->addPropertyConstraint('coordinates', new Assert\Unique([
            'fields' => ['latitude', 'longitude'],
        ]));
    }
}

message

type: string default: This collection should contain only unique elements.

This is the message that will be shown if at least one element is repeated in the collection.

You can use the following parameters in this message:

Parameter	Description
{{ value }}	The current (invalid) value

normalizer

type: a PHP callable default: null

This option defined the PHP callable applied to each element of the given collection before checking if the collection is valid.

For example, you can pass the 'trim' string to apply the :phpfunction:`trim` PHP function to each element of the collection in order to ignore leading and trailing whitespace during validation.