1. The `Doctrine\DBAL\Driver\DriverException::getErrorCode()` method is removed. In order to obtain the driver error code, please use `::getCode()` or `::getSQLState()`.
2. The value returned by `Doctrine\DBAL\Driver\PDOException::getSQLState()` no longer falls back to the driver error code.
## BC BREAK: Changes in `OracleSchemaManager::createDatabase()`
The `$database` argument is no longer nullable or optional.