Create files and compare data

Question

I have an aplication that can recive data (an integer and string), it stores it in a datafile and adds the date and time.  However, I need that everytime a new set of data cames, it ctompares it with the rest of the data stored in the same file.  If it the integer (key)  is repeated, it should be stored in a different file if not, it should be stored there.  
I been able to read and write data files in different vi, but I can't makean  application that does everything at the same time.  I will appreaciate any suggestions.   I'm new with LabView and there is a lot I dont know yet. 
Thank you!!!!

Answer 1

Thanks for your suggestion.  However, the main problem is not how to read and write together but how to compare the data.  I started by writing and reading vi becuase I wanted to insolate every part of my program, be sure it works and then build on top of it.   The complete application should do something like:
--Open two files, one for new data, one for repeted data
-- User enters data -> a key as integer and some string
-- compare the new key with ALL the keys already stored in the file.
      -- if the file is empty or no key is found in the file, write the data in the file for new data
     -- If the key is repeted, write the data in the file for repeted data
-- Keep doing this until the user stops the application.
What I really need is to be able to compare the recent entered data to what was entered before.  I chose to save data in a datalog because it seemed the best solution and because I also needed to store the date and time.  However, if there is any other way to store the data and compare it, please let me know.  I tried arrays and clusters by themselves but it wasnt easy.  Datalogs worked fine storing data but now comparing is too hard because I dont know how to read the file, record by record while comparing it to the new data I just got.
I hope this is a little bit clearer!