Marshalling support is useful. SQL result -> struct and struct -> SQL insert code is repetitive to write. Getting fancier than that may be overkill.

Marshalling in general needs more compile-time support. Kludges such as Google protocol buffer preprocessors are a fast but clunky way to do it. It would be useful if languages could be given a reference to an SQL CREATE TABLE and could use that information usefully. Field names, type information, and enum values should come from the CREATE TABLE info.