Most methods in the Berkeley DB classes return an int but also throw an
DbException object. This allows for two different error
behaviors, that are known as error models. The errorModel
argument is one of the following enumeration values:
Throw an exception whenever a serious error occurs. This generally
allows for cleaner logic for transaction processing, as a try block
can surround a single transaction. This is the default error model.
Do not throw exceptions, instead each individual function returns
an error code on error.