So far, only tables belonging to the SAME database could be copied.
Copying tables between databases from different sources (HSQLDB 1.8/2.3, MySQL, PostGres, Sqlite)
is admitted.
Field type conversions are in this case based on empiric rules.
A case study based on getMetadatInfo() is available on request.

Change-Id: Iae4ea7c4df4799cde3c8f973746513bad56246d8