Thanks for the quick response, Kathey. Some comments inline...
On 12/10/10 10:09 AM, Kathey Marsden wrote:
On 12/10/2010 9:46 AM, Rick Hillegas wrote:
I am considering adding metadata wrapper functions to the Derby
product. I would like the community's feedback on how to expose these
functions.
Thank you Rick for this work. I have not looked closely at it but am
wondering if you are proposing that these be exposed as a stable or
unstable interface
I don't see much danger that the signatures of the functions will
change. They are pretty much the signatures of the corresponding
metadata methods. They might become redundant, though, if someone
implements the Information Schema. We also might rue our choice of
system schema and want to move the methods to another schema.
and also wonder if we have a
call syscs_util.syscs_load_metadata_wrappers( true ); , if there
should also a be an unload or if the load method should reload new
definitions.
I was thinking that you would unload the wrappers by invoking the new
system procedure like this:
call syscs_util.syscs_load_metadata_wrappers( false );
I can't remember if columns might get added for metadata calls with
new JDBC versions. It seems to me there is some sort of precedence
for this. Even if there is just a bug it would be great to be able to
drop and reload.
JDBC 4.0 added columns to some of the metadata ResultSets. JDBC 4.1 will
add a couple new methods to DatabaseMetaData. As you note, we should
make it possible to unload the old wrappers and load the new ones.
Again having not looked at this, I don't understand how confident we
will never want to change the wrappers, but it might be nice to first
just expose them on a Wiki page as unstable and subject to change
until they have been vetted
instead of putting them in the formal documentation right away.
Pardon my fear of compatibility commitments #:)
I share your concern about creating new compatibility commitments for a
large api. Documenting this on the wiki as an experimental feature
sounds prudent to me. This would discourage 3rd parties from building
tools using these wrappers. However, we would still be able to use the
methods ourselves and we could cite them in our tech support responses.
Thanks,
-Rick
Thanks
Kathey
