> I'm no authority, but in general, Firebird only sends back blob id's during
> primary select, and then fetches each blob you request individually. So
> conditionally requesting it should do what you want.

In general this is correct, but only if auto-commit is set to false. In
auto-commit mode Jaybird fetches all data to the client incl. the blob
contents (subrequests are performed automatically).

The rs.getBytes() will fetch all data in all cases, but rs.wasNull(...)
will only check a corresponding flag.

So the answer to the second question is "in case when auto-commit is
false, BLOB data will be fetched only when you perform rs.getXXX
methods, but if auto-commit is true (default value) blob contents will
be fetched for the complete result set at once".

Roman