Comparing received data with data in databse

Question

Hello..

I'm a beginner in C#.Net programming.
I'm working on RFID related project.

The RFID reader connected to PC serial port and I have done the terminal interface using C#.Net.
I would like to know how to compare the received ID in the serial port buffer with the ID I've saved in MS Access database?

What i'm trying to do is when the ID received, then it will be compared with a bunch of ID saved in the database, then the Richtextbox will display the details (saved in the database) of the matched ID.

Thanks ^^