Question

I’m doing my first experiments with Grails and am looking for a way to have fields represented by a combobox (such as one-to-one domain associations and numbers with a narrow range constraint) to be optional, i.e. there should be an empty entry in the combobox.

How can this be achieved? I’ve tried both adding a nullable:true constraint and listing the fields in the optionals static property, but neither produces the desired result.

These are my domain classes:

class Customer {     String name } class Book {     static optionals = ['year','loanedTo','loanedSince']     static constraints = {     title(blank:false)     author(blank:false)     year(range:1900..new Date().getAt(Calendar.YEAR), nullable:true)     loanedTo(nullable:true)     loanedSince(min:new Date())     }      String title;     String author;     Integer year;     Customer loanedTo;     Date loanedSince; } 

Answer 1

I’ve found that the nullable:true constraint actually does have the desired effect – however, it does not take effect immediately; you have to restart Grails to see it.