# nullable

## Purpose

Allows a property to be set to `null`. By default Grails does not allow `null` values for properties.

## Examples

    age(nullable:true)

## Description

Set to `true` if the property allows `null` values. This constraint influences schema generation.

> An empty form field will appear in the request parameters as an empty string, not as null. Keep this in mind when setting domain fields directly from request parameters.

Error Code: `className.propertyName.nullable`