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From Mike Matrigali <mikem_...@sbcglobal.net>
Subject Re: [jira] Created: (DERBY-2731) String literal constants currently take the collation of the compilation schema but the wiki page http://wiki.apache.org/db-derby/BuiltInLanguageBasedOrderingDERBY-1478 expects USER schema collation.
Date Wed, 30 May 2007 19:22:44 GMT
I know we are not implmenting it, but I think the decision should 
include thinking about a future Derby where a single database will
support columns with different collations.   In that case what is
the "user" schema? Does this affect the decision?

Does collation association remain fixed to the compile time decision?
Does the result of the query change if executed under different 
schema's, or do we recognize a change in schema and recompile?

Mamta A. Satoor (JIRA) wrote:
> String literal constants currently take the collation of the compilation schema but the
wiki page http://wiki.apache.org/db-derby/BuiltInLanguageBasedOrderingDERBY-1478 expects USER
schema collation.
> -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> 
>                  Key: DERBY-2731
>                  URL: https://issues.apache.org/jira/browse/DERBY-2731
>              Project: Derby
>           Issue Type: New Feature
>           Components: SQL
>     Affects Versions: 10.3.0.0
>             Reporter: Mamta A. Satoor
>             Assignee: Mamta A. Satoor
> 
> 
> I checked in code some time back which sets the collation type of string literal to be
same as the compilation schema. The advantage of this is that metadata queries will work without
changes since those queries do character string literal comparisons.
> 
> But the wiki page at http://wiki.apache.org/db-derby/BuiltInLanguageBasedOrderingDERBY-1478
in Section Collation Determination, Rule 1) says that character string literal should always
take the collation of user schema. This decision was based on the discussion in the Collation
feature discussion thread at http://www.nabble.com/Collation-feature-discussion-tf3418026.html#a9675967.
SQL spec defines the behavior here to be implementation defined (it says that in a convoluted
way which can be found in the Collation feature discussion). But considering the impact it
will have on the metadata queries (they will have to be changed so that we CAST character
string literals so that they will take the collation of system schema and hence the comparison
will not fail), should we reconsider our decision made on the wiki page. 
> 

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