ID That Will Never Be Used

I'm writing some tests for a Django application and in these tests I need to provide an ID for the view in question. I also need to test for an ID that is not in the DB. At the moment I am using 99999999999 as a stand in for an ID I know that isn't in the DB.

Is there an ID I can use that will never be used? I ahve heard some DB's won't use zero. The DB is in question is mySQL version 14.14. I would like to have my solution be as DB agnostic as posisble since we would like to move the project off of mySQL.