Version 4 supported
This version of Silverstripe CMS is still supported though will not receive any additional features. Go to documentation for the most recent stable version.

Validation and constraints

Traditionally, validation in Silverstripe CMS has been mostly handled on the controller through form validation.

While this is a useful approach, it can lead to data inconsistencies if the record is modified outside of the controller and form context.

Most validation constraints are actually data constraints which belong on the model. Silverstripe CMS provides the DataObject::validate() method for this purpose.

By default, there is no validation - objects are always valid! However, you can overload this method in your DataObject sub-classes to specify custom validation, or use the validate hook through a DataExtension.

Invalid objects won't be able to be written - a ValidationException will be thrown and no write will occur.

It is expected that you call validate() in your own application to test that an object is valid before attempting a write, and respond appropriately if it isn't.

The return value of validate() is a ValidationResult object.

namespace App\Model;

use SilverStripe\ORM\DataObject;

class MyObject extends DataObject
    private static $db = [
        'Country' => 'Varchar',
        'Postcode' => 'Varchar',

    public function validate()
        $result = parent::validate();

        if ($this->Country == 'DE' && $this->Postcode && strlen($this->Postcode) != 5) {
            $result->addError('Need five digits for German postcodes');

        return $result;

API documentation