In my current lucene index I want to be able to find documents by their isocountry code so I store this as an indexed field, but I also want to to find documents that do not have a country code so when building the index I store an '-' in the field for that record if they have no country code.
This applies to other fields as well, and it means that as well as increasing the size of my index there are indexing problems if the '-' is valid real data for the field.
Is there a better way of doing this in the latest versions of lucene ?