"Upload" program online

Noob question, but I have to ask:

I've always wrote programs that

• Starts
• Do their job
• Ends

For my next assignment I should create a program that:

• Starts
• Wait for fields in Database
• Edit them
• Create an output

For the editing and output there's no problem, but I don't know how to act for the first part. I mean, I know I can just loop check a database and retrieve fields until it's empty, but how can I achieve the loop part without leaving my pc turned on 24/24? Should I "charge" my program somewhere online? Where? What kind of services can offer me an host of this type? What's the common solution to this?