FMDB initialisation and Upgrade database version in iOS

I am using FMDB and Sqllite for my iOS application. I know about how to create Database and Table programatically but i am confuse where to write code so, it run first time. If i write code in application:didFinishLaunching method then it run every time when i open app. Is there any methode where I can Initialise/Create Database and Database Tables?

Another question is suppose I need to do some changes in database when upload new version of app then in which methode i need to write code so, it execute first time only?

Looking forward to hear from you.

Thank You, Shailesh