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From Bryan Pendleton <bpendleton.de...@gmail.com>
Subject Re: productizing the metadata wrapper functions
Date Sat, 11 Dec 2010 04:27:06 GMT
> These wrapper functions let you use SQL to examine
> database, ResultSet, and parameter metadata.

The database metadata table function seems quite natural and powerful.

I'm less clear on how to use the RS and Parameter functions; I looked
at the examples in DERBY-4926 and DERBY-4927 but they seemed pretty
artificial. Do you have more substantial examples? Also, would these
latter two functions be useful in a JDBC program? Or are they something
that would mostly be useful in IJ?

I guess what I'm asking is: could I somehow pass an actual ResultSet
object or PreparedStatement object to one of these functions? Or do
they always have to take a query string and compile it themselves?

Lastly, why does it take several seconds to register these functions?
Is it due to how they are packaged? (That is, if they were embedded
in derby.jar would the registration go faster?) I'm a bit surprised
that something as seemingly trivial as registering three table
functions could take that much time.

Anyway, thanks very much for doing this work, and for advancing the
proposal; it's quite interesting and I've been learning a lot by
reading your work and following the discussions!


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