Additional Database Handler Interface and Class Implementation

**Describe the solution you'd like**
Additional DB Interfaces and Class Implementations

No files, interfaces, classes, or tests are named. Start by locating the existing database handler interfaces and implementations in the repository, then determine which additional ones are intended; the work is done when the requested interfaces and class implementations are defined consistently with the existing design and validated by the repository's available tests.

Written by the indexing model from the issue text.