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https://issues.apache.org/jira/browse/DERBY-2335?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mamta A. Satoor updated DERBY-2335:
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Attachment:
DERBY2335_correct_collation_for_constants_persistent_column_v1_stat.txt
DERBY2335_correct_collation_for_constants_persistent_column_v1_diff.txt
Attaching
patch(DERBY2335_correct_collation_for_constants_persistent_column_v1_diff.txt)
which does couple of things
1)It puts the correct collation type for character constants and for persistent
character columns. For character constants, the collation type will be the
collation type of the schema in which the query is getting compiled. This
happens in
CharConstantNode.bindExpression. The setting of collation type for the
persistent columns happens in a constructor for the DataTypeDescriptor. This
could be found in the patch which has changes for DataTypeDescriptor and
TypeDescriptorImpl.
2)Collation related methods (like and stringCompare) on collation sensitive
DVDs has been copied into WorkHorseForCollatorDatatypes. These methods get
called by CollatorSQLxxx classes.
3)The final change went into CollationTest. The change now allows this test to
test collations for Norway, English and Polish.
I will add more tests for these changes in a subsequent patch.
> Compare character datatypes with different collation ordering.
> --------------------------------------------------------------
>
> Key: DERBY-2335
> URL: https://issues.apache.org/jira/browse/DERBY-2335
> Project: Derby
> Issue Type: Sub-task
> Components: SQL
> Affects Versions: 10.3.0.0
> Reporter: Mamta A. Satoor
> Assigned To: Mamta A. Satoor
> Attachments:
> DERBY2335_correct_collation_for_constants_persistent_column_v1_diff.txt,
> DERBY2335_correct_collation_for_constants_persistent_column_v1_stat.txt
>
>
> The parent task DERBY-1478 will enable users to have a different collation
> order for user-defined character datatypes compared to UNICODE based
> collation, UCS_BASIC, used by system tables. This sub-task is added to handle
> the case where a comparison is made between character datatypes with
> different collation order.
> For instance
> Let's say, a database is created to use a territory based collation for
> character types. And say there is a userSchema schema in that database which
> has a table tableInfo with column tablename defined as VARCHAR. This
> tableInfo.tablename will have territory based collation assoicated with it.
> And say this column is then compared with a VARCHAR column in SYS schema,
> then how will the comparison happen, since the 2 columns being compared have
> different collation associated with them?
> select * from sys.systables and userSchema.tableInfo where
> systables.tablename = tableInfo,tablename
> Thanks to Rick for taking the time out on this issue. He had following
> suggestion
> </Rick comment start>
> "As I read part 2 of the SQL Standard, it looks like you need a CAST in order
> to compare 2 strings which have different collations bound to them. Both
> string operands must have the same collation--that is my reading of Syntax
> rule 3b in section 9.13. Sections 6.12 and 6.1 explain how to cast the
> operands so that you can compare them. I think you need to write an
> expression like this:
> WHERE userStringCol = CAST ( systemStringCol AS VARCHAR COLLATE
> userStringColumnsCollation )
> Here's an example I googled up:
> http://docs.openlinksw.com/virtuoso/sqlrefDATATYPES.html. Hope this helps.
> </Rick comment end>
> When this task is taken up, it would be good to explore Rick's suggestion.
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