Dmitry,

>I'm interested in reverse case - when one connection use
>two or more databases on the same server.
>I understand that implementation needs extending syntax, but
>how much work needed to do engine changes for this? Your comments?

Technically it would be two connections, but transactions
could span connections. At the moment, our DSQL has no way
to indicate the source of a table. That's a language issue.
We could support a main query against one database and
subqueries against another reasonably easily. Joins would
be more of a problem, and cross database procedures, triggers,
constraints, etc. even more. Not impossible, not without
value, just hard.

Best,

Ann

Yes, this has been discussed, on this list, I think.