If you want to view your database when running on Simulator it is located at the following location
user/Library/Application Support/iPhone Simulator/version of SDK(4.2eg)/Applications/4AF938D6-E981-4971-A588-3424B64E7EE7(eg)/Documents/yourdatabase.sqlite
If you want to view the database in your device then you can use a software like iExplorer
.
Cheers
Edit : The location of sqlite file has changed.
It currently resides in :
/User/Library/Application Support/iPhone Simulator/version of SDK(eg-7.0)/Applications/4AF938D6-E981-4971-A588-3424B64E7EE7(eg)/Library/Application Support/app_name/yourdatabase.sqlite
Edit : The location has changed again. It now resides in:
/User/Library/Developer/CoreSimulator/Devices/789A1317-6C55-4615-A72E-65C824D8C6B9(eg)/data/Containers/Data/Application/0470F5FC-0043-46B7-A21C-A436A56ED714(eg)/Documents/yourdatabase.extension