Android SQLite Database Programming Developing Database 

I want to create a SQLite database in my app, which contains three tables, I will add data into tables and will use them later on.

but I like to keep database ,as if when app is first time installed it checks whether the database exist or not, if exists it updates it else if not then creates a new database.

further more I am making a DB class to facilitate my app,so I wont be creating an activity for my database creation.

if there are possible advices, please share with me