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From "Mamta A. Satoor (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-2336) Enable collation based ordering for CHAR data type.
Date Tue, 06 Mar 2007 22:41:24 GMT

    [ https://issues.apache.org/jira/browse/DERBY-2336?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12478614
] 

Mamta A. Satoor commented on DERBY-2336:
----------------------------------------

Thanks for your time on this Jira entry, Dan and Mike. Has been very helpful.

I talked to Dan offline on this issue and just wanted to summarize the conversation here.

One of the goals for this Jira entry is not to burden the existing SQLChar datatype with collation
information because they work greate for the deault ordering which is UCS_BASIC. For the territory
based collation, we should have new subclass(es) of existing char datatypes which will use
the territory based collation to do the sorting. One of the tasks identified for the new subclasses
is how to get the required collation information to them so that their sorting will be based
on territory. I am going to tackle this in incremental step by may be hardcoding some kind
of collation in new char datatypes and make sure that it works fine. The next task would be
to get the collation infromation correctly from the compile phase into the new data types
instances. 

The next task is to see how recovery can be implemented so that the new datatypes will have
the correction collation associated with them when they are instantiated during recovery.
One way, which is not a practical solution, is to have these new datatypes write their collation
information onto the disk. But doing so will mean that same collation information will be
duplicated in all the instances of these new datatypes and that is not very efficient. Ideal
solution would be to have this collation informaiton available at table level or databse level
and use that information at recovery time to create the correct collation for the new char
datatypes.

As a first step, I am going to concentrate on creating subclass of SQLChar which will have
a specific collation hardcoded into it and have the compiler use those new subclasses.

If anyone has any comments, plese share them.

> Enable collation based ordering for CHAR data type.
> ---------------------------------------------------
>
>                 Key: DERBY-2336
>                 URL: https://issues.apache.org/jira/browse/DERBY-2336
>             Project: Derby
>          Issue Type: Sub-task
>          Components: SQL
>    Affects Versions: 10.3.0.0
>            Reporter: Mamta A. Satoor
>         Attachments: DERBY_LocalFinder_CodeCleanup_diff_V01.txt, DERBY_LocalFinder_CodeCleanup_stat_V01.txt
>
>
> I am breaking down the Parent task DERBY-1478 (Add built in language based ordering and
like processing to Derby) into multiple sub tasks. One of them is to concentrate on enabling
the collation based ordering on (hopefully the simplest of all the character data types) CHAR
data type. This task in itself might need subtasks if it is later found that it can be subdivided
into multiple smaller steps.

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