question: protected void writeNullReferenceRow ( AbstractRecord record ) { List < DatabaseField > fields = getReferenceFields ( ) ; int size = fields . size ( ) ; boolean nullInserted = false ; for ( int index = 0 ; index < size ; index ++ ) { DatabaseField field = fields . get ( index ) ; if ( ! field . isReadOnly ( ) && ( field . isUpdatable ( ) || field . isInsertable ( ) ) ) { record . put ( field , null ) ; nullInserted = true ; } } if ( size > 0 && nullInserted ) { record . setNullValueInFields ( true ) ; } }
target:  INTERNAL: Write null values for all aggregate fields into the parent row.