I’m currently developing a Play! application, and I use Heroku to deploy and test it.
But sometimes when deploying it, the application crashes when trying to start up. What happens is that the database contains data that are in conflict with the new schema that I’ve deployed (eg. new required foreign keys that don’t have a value…).
To fix this, the easiest way I’ve found is to reset my Heroku database. When connected to Heroku (with the Heroku Toolbelt), just run
heroku pg
which will display the list of your databases, then run
heroku pg:reset HEROKU_DATABASE_SOMEBASE
which will reset your database HEROKU_DATABASE_SOMEBASE.
Then you can restart your application with
heroku restart
and everything should be working fine.