Sqlite3, OperationalError: unable to open database file

I faced exactly same issue. Here is my setting which worked.

'ENGINE': 'django.db.backends.sqlite3', 
'NAME': '/home/path/to/your/db/data.sqlite3'

Other setting in case of sqlite3 will be same/default.
And you need to create data.sqlite3.

Django NewbieMistakes

PROBLEM You're using SQLite3, your DATABASE_NAME is set to the database file's full path, the database file is writeable by Apache, but you still get the above error.

SOLUTION Make sure Apache can also write to the parent directory of the database. SQLite needs to be able to write to this directory.

Make sure each folder of your database file's full path does not start with number, eg. /www/4myweb/db (observed on Windows 2000).

If DATABASE_NAME is set to something like '/Users/yourname/Sites/mydjangoproject/db/db', make sure you've created the 'db' directory first.

Make sure your /tmp directory is world-writable (an unlikely cause as other thing on your system will also not work). ls /tmp -ald should produce drwxrwxrwt ....

Make sure the path to the database specified in settings.py is a full path.

Also make sure the file is present where you expect it to be.