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From Joerg von Frantzius <joerg.von.frantz...@artnology.com>
Subject Derby-134, indexes and sorting locale-sensitive / case insensitive
Date Fri, 22 Apr 2005 08:12:19 GMT
Hi,

there had been a long discussion of Derby-134 ("Sorted string columns are sorted in a case
sensitive 
way"), which in the end looked to me as being solved, i.e. someone has supplied a "good-looking"

patch. Now is there any chance of a binary build coming up in the near future, where this
patch 
would be included?

Talking about "ORDER BY", after reading the manuals about optimization and in particular 
http://incubator.apache.org/derby/manuals/tuning/perf45.html#Cost-Based+ORDER+BY+Sort+Avoidance
I'm still not sure about a few things. My problem is that I have a GUI with a table widget
that 
displays >1500 rows, and I want to make use of Derby's index structures to have fast column
sorting. 
Maybe that simply won't help here, because I need the ordering to be both locale-sensitive
and 
case-insensitive.

With an ascending index on a VARCHAR column:
1. does that index default to case-insensitive ordering of the column?
2. does it maintain the ordering  in a locale-sensitive way, e.g. by using java.text.Collator?
(e.g. 
using the default locale active at index creation time)
3. will "ORDER BY ... DESCENDING" make use of the index by simply reversing its order, or
will it 
result in full re-sorting with performance-penalty?

Thanks for any information,
Jörg.


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