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https://github.com/silverstripe/silverstripe-framework
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49 lines
1.5 KiB
Markdown
49 lines
1.5 KiB
Markdown
title: Model Validation and Constraints
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summary: Validate your data at the model level
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# Validation and Constraints
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Traditionally, validation in SilverStripe has been mostly handled on the controller through [form validation](../forms).
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While this is a useful approach, it can lead to data inconsistencies if the record is modified outside of the
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controller and form context.
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Most validation constraints are actually data constraints which belong on the model. SilverStripe provides the
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[api:DataObject::validate()] method for this purpose.
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By default, there is no validation - objects are always valid! However, you can overload this method in your DataObject
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sub-classes to specify custom validation, or use the `validate` hook through a [api:DataExtension].
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Invalid objects won't be able to be written - a [api:ValidationException] will be thrown and no write will occur.
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It is expected that you call `validate()` in your own application to test that an object is valid before attempting a
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write, and respond appropriately if it isn't.
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The return value of `validate()` is a [api:ValidationResult] object.
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:::php
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<?php
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class MyObject extends DataObject {
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private static $db = array(
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'Country' => 'Varchar',
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'Postcode' => 'Varchar'
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);
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public function validate() {
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$result = parent::validate();
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if($this->Country == 'DE' && $this->Postcode && strlen($this->Postcode) != 5) {
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$result->error('Need five digits for German postcodes');
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}
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return $result;
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}
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}
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## API Documentation
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* [api:DataObject]
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* [api:ValidationResult];
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