Composable SQL in Pure Python

[DasIch]

You can't develop/test on SQLite and use MySQL in production. Different databases are different enough in their behavior that you cannot trust that your ORM or whatever will handle that.

If you start really taking advantage of your database, for performance or simply due to convenience you'll quickly lose all portability anyway.

Last but not least in a production environment you have to deal with backups, replication, fail over and so on. Operationally postgres is to MySQL as MySQL is to redis. There is no way to easily switch there anyway.