I would like to establish a connection between a mobile device and computer so they can interact with each other. I should be able to send and receive data at both the ends, just like a chat client. How do I go about it? I just want to know the steps involved. I was thinking about sending the data from the device to a database server and then accessing it through the PC, and doing the same on the mobile device, too. Is this a good idea? What alternatives are there?
Since you're using android, this is pretty easy. One easy option is to code a client and server application for your android device and pc. Or, you could just send data on the UDP connectionless protocol.
I'm assuming you know how to build apps for an android phone. There is no need of an intermediate node (a database server or the like), if the goal here is as small as just sending data back and forth.
Here's a good example of a UDP server/client implementation. And here's a good one for TCP server/client.
Hope that helps.