The Data Tool can be used both to populate a brand new store
with product data and to update an existing store. In cases where you
are updating a store, there are three options as to how you handle
existing data already in the
store:
Add imported data to
existing data and ignore duplicates - do this if your site
database data is the 'master' version, and you've made corrections and
changes to it, or are just confident existing data is already
perfect
Add imported
data to existing data and update duplicates - in this case,
any duplicates in the destination will be updated from the source
data
Reset database
and import - this will clear existing data, and then import
the data so you retain no previous data
Depending on where you are importing data from (CactuShop,
Kartris or spreadsheet), there are also a variety of filters to
control what data is updated.