> The exceptions that are still thrown (after the fix) are related to
> opening datasets in various circumstances.
>
> Example:
> If you use dataset calculated event to calculate a value from another
> dataset and you open the other dataset from the event the exeption
> is thrown

I think I know what is happening in you case...

Is it correct, that you use single Database component and two QueryDataSet
components connected to the same Database? And when you open the connection,
you do not set auto-commit property to false?

In this case JayBird 2.0 behaves according to the JDBC 3.0 specification -
it is required to close open query before another one is executed (your
second QueryDataSet in the calcFields event) in auto-commit mode.

If that is your case, there's not much to do. You rely on a documented
deviation from the specification in JayBird 1.5.x which is fixed in JayBird
2.0 (in fact, previous issue was related to the same problem, however driver
went to far by treating metadata queries as regular ones). You have to
either redesign your application (for example use two Database components)
or set the auto-commit mode to false.

Roman