Hi Darcy,
Thanks for this update. I will unassign DERBY-396. I will happily to
mouse into DERBY-396 any information you think is worth forwarding.
Regards,
-Rick
Darcy Benoit wrote:
Rick,
Scott was one of my students, and he was working on DERBY-396. He
has since graduated and moved on from our university. He ran into some
problems with DERBY-396, which can simply be summed up as problems
with return values. When you are accessing a table to alter it, you
need to lock the table in order to keep other users from altering the
table at the same time. Once the change has been made, you can then
release the lock on the table, which is essentially a "return". This
isn't a problem when you are adding columns, as there is nothing to
return. But the existing circumstance for RENAME and DROP require that
the object being renamed or dropped is returned. This results in a
case where you have a return within a return - something that doesn't
work so well with Java. He tried several different ways to work around
this problem, including not returning the objects when performing
RENAMEs and DROPs, returning only the node but not the lock, and
casting the node to be renamed o
r dropped as the same object type as the return type. He also tried
calling separate rename or drop methods, but the object being returned
was not the same type as the object type returned by the alter table
commands.
The result on his final report was "Due to time constraints and
the problems of requiring rename and drop statements to return values
inside the alter table method, I was not able to implement the rename
and drop column functionality."
I had suggested to Scott that he release working on the feature
once he had graduated until he was able to begin working on the
project again on his own time. I guess that he didn't get around to
doing that. :(
I have a hard copy of his final report, but I can try to relay any
information from it to whoever would like to know.
darcy
Hi Scott,
Please forgive me for putting you on the spot by paging you in the
subject line of this message. I
have tried to privately ping your JIRA email address ([EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>), but the mail bounced back.
You graciously volunteered to work on DERBY-396. The community wants
to know whether you'll be
able to check in some of your code for the upcoming 10.2 release.
Please feel free to ask the
community for advice. Many people are keen to see this feature and
would be delighted to help out
any way they can.
Thanks,
-Rick
