Which course is best in Information technology ... data base administration Or Network administration ? World Wide Demand ????

Depends on your preference and ability. Only you can judge that.

Worldwide demand is on App development at the moment, that's where the money is.

Accredited colleges and private computer schools offer a range of training programs in today's hottest database technologies, including Microsoft SQL Server, Oracle and IBM DB2. Compare the top-rated database courses & degrees 

You need to answer to yourself... which computer books you are quickly understand and able to grasp the logic. You need to choose that.. before you look at world demand, you need to check your ability. Not all are doing perfect when choosing not by their own choice but by 'world demand'. If you want success, you must choose what you able to understand better.