Here is my problem, it's looking kind of complicated to me, but maybe it's because I've confused myself. so i need an outside opinion. (that's you guys)

Ok.

I have this data, which is from testing a device. this data, which can be rather extensive, is written into a comma delimited text file.

What I am doing, is taking said text files and importing them into access using my vb code, and then doing queries and all that good stuff on the data, to eventually manipulate it into an output excel document.

but, what I am doing right now in this, is trying to prevent duplicate data.

Is there a way I can do this BEFORE inserting the data into the database?
check the data to be imported vs. the existing data?

There should never be duplicate data (start times, part numbers, serial number and whatnot), UNLESS the user has retested a device and wants to keep both sets of data.

Right now I'm kind of unsure about HOW I want to test the data, or govern what constitutes duplicate data.

But is there a way to test before the insertion?

like treat the text file like a database, and do a normal sql query on it to see if the first entries match (make sure same file is not imported twice), or something along those lines?

I think I've just really mixed myself up, haha.
Any suggestions on how to go about this?