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From Apache Wiki <wikidi...@apache.org>
Subject [Db-derby Wiki] Update of "Tiago_Espinha" by TiagoEspinha
Date Thu, 08 Apr 2010 20:09:30 GMT
Dear Wiki user,

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The "Tiago_Espinha" page has been changed by TiagoEspinha.
http://wiki.apache.org/db-derby/Tiago_Espinha?action=diff&rev1=7&rev2=8

--------------------------------------------------

  
  Right now when the client driver is used, the requests are piped through the DRDA engine.
In Derby’s implementation of DRDA, the requests are encoded using EBCDIC [4] and this encoding
uses an 8-bit representation which limits the number of characters it can represent by 256.
This limitation is fine when it comes to US-ASCII characters (a sub-set of EBCDIC) but it
does not encode the thousands of Chinese and Japanese characters. For this, we require a broader
encoding such as UTF-8. Since backwards compatibility is always an issue, we must also ensure
that not only the new character encoding is put into place, but that the older encoding types
are still supported.
  
+ There is currently an Architecture Change Request (ACR7007) [5] with The Open Group undergoing
fast track review to make this change an actual component of the DRDA specification.  This
ACR proposes that an encoding is agreed at the EXCSAT stage between the Application Requester
(AR) and Application Server (AS). This encoding can then be the default EBCDIC or UTF-8 for
the added range of characters. It is this encoding that is then used for commands following
the ACCSEC (which is still negotiated using the normal EBCDIC encoding).
+ 
- In the meanwhile, I have also setup my build environment and I have also taken on a smaller
task [5] that will help me build up to the main one. According to my mentor, this project
would ideally be undertaken by someone with previous experience in contributing to Derby and
as such, I qualify for the task. Also, if my project turns out to be ahead of schedule and
I finish early, I will also continue my last year project by assisting with the other issues.
+ In the meanwhile, I have also setup my build environment and I have also taken on a smaller
task [6] that will help me build up to the main one. According to my mentor, this project
would ideally be undertaken by someone with previous experience in contributing to Derby and
as such, I qualify for the task. Also, if my project turns out to be ahead of schedule and
I finish early, I will also continue my last year project by assisting with the other issues.
  
  I am still passionate about developing software and as a fresh graduate I can also use all
the experience I can get. This program provides students with that experience and I am thrilled
to be a part of it again.
  
@@ -48, +50 @@

  === References ===
  [1] http://bit.ly/TiagoASF
  
- [2] https://issues.apache.org/jira/browse/DERBY-728
+ [2] [[https://issues.apache.org/jira/browse/DERBY-728|DERBY-728]]
  (“Unable to create databases whose name containg Chinese characters through the client
driver”)
  
- [3] http://issues.apache.org/jira/browse/DERBY-4009
+ [3] [[http://issues.apache.org/jira/browse/DERBY-4009|DERBY-4009]]
  (“Accommodate length delimited DRDA strings where character length does not equal byte
length”)
  
- [4] http://www.hansenb.pdx.edu/DMKB/dict/tutorials/ebcdic.php
+ [4] [[http://www.hansenb.pdx.edu/DMKB/dict/tutorials/ebcdic.php|EBCDIC Table]]
  
+ [5] [[http://issues.apache.org/jira/secure/attachment/12405588/ACR7007.pdf|ACR7007]]
+ 
- [5] https://issues.apache.org/jira/browse/DERBY-4584
+ [6] [[https://issues.apache.org/jira/browse/DERBY-4584|DERBY-4584]]
  (“Unable to connect to network server if client thread name has Japanese characters”)
  
  

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