Cover of the book Symfony 5: The Fast Track

Symfony 5: The Fast Track is the best book to learn modern Symfony development, from zero to production. +300 pages in full color showing how to combine Symfony with Docker, APIs, queues & async tasks, Webpack, Single-Page Applications, etc.

Buy printed version
Buy PDF version
  1. Home
  2. Documentation
  3. Reference
  4. Constraints
  5. IsNull
WARNING: You are browsing the documentation for Symfony 2.3 which is not maintained anymore. Consider upgrading your projects to Symfony 5.1.

IsNull

2.3 version
Maintained
3.4 4.4 5.1 current 5.2 master
Unmaintained
2.7 2.8 3.0 3.1 3.2 3.3 4.0 4.1 4.2 4.3 5.0

IsNull

Validates that a value is exactly equal to null. To force that a property is simply blank (blank string or null), see the Blank constraint. To ensure that a property is not null, see NotNull.

Also see NotNull.

Applies to property or method
Options
Class Symfony\Component\Validator\Constraints\IsNull
Validator Symfony\Component\Validator\Constraints\IsNullValidator

Basic Usage

If, for some reason, you wanted to ensure that the firstName property of an Author class exactly equal to null, you could do the following:

  • Annotations
     1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
    // src/AppBundle/Entity/Author.php
namespace AppBundle\Entity;

use Symfony\Component\Validator\Constraints as Assert;

class Author
{
    /**
     * @Assert\IsNull()
     */
    protected $firstName;
}
  • YAML
    1
2
3
4
5
    # src/AppBundle/Resources/config/validation.yml
AppBundle\Entity\Author:
    properties:
        firstName:
            - 'IsNull': ~
  • XML
     1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
    <!-- src/AppBundle/Resources/config/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 http://symfony.com/schema/dic/constraint-mapping/constraint-mapping-1.0.xsd">

    <class name="AppBundle\Entity\Author">
        <property name="firstName">
            <constraint name="IsNull" />
        </property>
    </class>
</constraint-mapping>
  • PHP
     1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
    // src/AppBundle/Entity/Author.php
namespace AppBundle\Entity;

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

class Author
{
    public static function loadValidatorMetadata(ClassMetadata $metadata)
    {
        $metadata->addPropertyConstraint('firstName', Assert\IsNull());
    }
}

Options

message

type: string default: This value should be null.

This is the message that will be shown if the value is not null.

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.