
Db is an efficient and enchanced thin layer over JDBC that significantly simplifies writing of database code. Using pure JDBC api correctly requires writing the same code snippets over and over again, what easily leads to unmaintainable application. So often there are run-time problems just because of incorrect database handling. Db introduces several smart façades that helps in writing smaller, cleaner and maintainable code.
DbOrm is the mapper between object and relational world using plain SQL queries. It defines object-table mappings using annotations or naming convention. On the other hand, relationships are not pre-defined, they are set on very place where used. The best way how to think of DbOrm is from the JDBC perspective: it is not a full-blown complex ORM library; instead, it is just a nice tool built over Db for efficent database work.