Example of using composite primary key

CompositeDomainClass.groovy

class CompositeDomainClass implements Serializable {
  //this is part of the pk
  MyOtherDomainClass otherDomainClass
  //other fields here...
  //and we try to map this
  static mapping {
    table 'composite_table'
    id composite: ['id','otherDomainClass'], column: 'my_code_field'
    otherDomainClass(column: 'other_table_id')
  }
}