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From Apache Wiki <wikidi...@apache.org>
Subject [Db-derby Wiki] Update of "BuiltInLanguageBasedOrderingDERBY-1478" by MamtaSatoor
Date Wed, 21 Mar 2007 16:24:48 GMT
Dear Wiki user,

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The following page has been changed by MamtaSatoor:

  9)CollatorSQLChar has a method called getCollationElementsForString which currently gets
called by like method. getCollationElementsForString gets the collation elements for the value
of CollatorSQLChar class. But say like method is looking for pattern 'A%' and the value of
CollatorSQLChar is 'BXXXXXXXXXXXXXXXXXXXXXXX'. This is eg of one case where it would have
been better to get collation element one character of CollatorSQLChar value at a time so we
don't go through the process of getting collation elements for the entire string when we don't
really need. This is a performance issue and could be taken up at the end of the implementation.
Comments on this from Dan and Dag can be found in DERBY-2416. 
+ 10)Add tests for this feature. This a broad umbrella task but I do want to mention 2 specific
tests that we should be testing
+ a)Make sure the scale of the character datatypes is always 0 and it didn't get impacted
negatively by the overloading of scale field as collation type in TypeDescriptor.
+ b)Test case for recovery - have an outstanding transaction with insert/delete/updates that
affect one or more character indexes (all with a collation setting that is different from
default collation). Make sure those log records get to the log and then crash the server.
Restarting the server will then run through the recovery code and will ensure that we test
for correct collation usage at recovery time. Mike has put more info about this in DERBY-2336.
  == Implemented items ==
  1)A shell for subclass of SQLChar has been implemented and it is called CollatorSQLChar.
It resides in derby.iapi.types package. This work was done by revisions 516864, 516869 and

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