For the implementation of the Dao's there has been always followed one of the folloging structures:

Inheritance Approach

This approach is only used once for one Dao: ClassificationSchemeDao for all entities which are extending ClassificationScheme of the coreisometadata.

Package Approach

This is the most often used approach. A Dao is used as the accessor to one or more logically grouped packages. The packages may be subpackages of a certain package.