nullable
Purpose
Allows a property to be set to null. By default Grails does not allow null values for properties.
Examples
age nullable: trueDescription
Set to true if the property allows null values.
This constraint influences schema generation.
Error Code: className.propertyName.nullable
Web requests resulting from form submissions will have blank strings, notnull, for input fields that have no value. Keep this in mind when doing mass property binding to properties that are not nullable. The default behavior is such that a blank string will not validate fornullable: falsesince the data binder will convert blank strings to null. This includes empty strings and blank strings. A blank string is any string such that thetrim()method returns an empty string. To turn off the conversion of empty strings to null set thegrails.databinding.convertEmptyStringsToNullproperty tofalseinConfig.groovy. See the data binding section for more details on data binding.
// grails-app/conf/Config.groovy// the default value for this property is true grails.databinding.convertEmptyStringsToNull = false
// ...