A similar question that I answered not very long ago:
How to import excel data to SQL database table[
^]
Once you understand how to do this, you can easily validate the data before saving as well. You just have to loop through the collection and see if that country exists in the db or not. And the way you check whether it exists in db or not, is to do a select query for that name and see if any results are returned (pretty basic really).