I assume the table has proper ID-keys. In that case you could use an
appendquery. All the records which are already in the table will be skipped.
Records that aren't in the table yet will be added. There are a couple of
things you need to keep in mind: Is this table not related to other tables,
because in that case you might have to update the related tables as well.
Remember before you jump into any action to make a copy of the database
before you actually are going to do some processing.

hth