Anyone could help me on building of an online-flilght,hotel,car,cruises reservation system? the requirement for the website will be similar to www.orbitz.com, www.priceline.com. And i am mainly concerned about: To keep all the details in own's database or get that from other systems. If we keep all the details of the hotel, flight, car, Activities, Crusies in our own databases, there should be a medium of updating their information to all connected partners,how we could do that?what would be the way if i am going to use some form of API for accessing information. Please if any item kindly share. Thank you.