Update/insert How To Determine Which In Code

Queries are run on a webpage:
The queries would be a little bit different – instead of just one operator, it would get all operators for each category and then either create a record in Access (if it didn’t already exist) or update a record (if it already existed). For example, the first query might get

JSMITH 22
KWALTON 33
Since these records don’t exist yet, we’d do an insert for each. If the next query (for a different entry/verify category) got

JSMITH 44
VJONES 50
we would update JSMITH (since already inserted after first query) and insert VJONES. This has to be done since not everyone works in every category. Not sure if you can import different spreadsheets into Access and have it determine automatically for each row whether to do an insert or update (of course, we can do this in code in the web page).

Can you help?