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From "Mike Matrigali (JIRA)" <j...@apache.org>
Subject [jira] Updated: (DERBY-3330) provide support for unique constraint over keys that include one or more nullable columns.
Date Thu, 06 Mar 2008 20:12:57 GMT

     [ https://issues.apache.org/jira/browse/DERBY-3330?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Mike Matrigali updated DERBY-3330:
----------------------------------

    Derby Info: [Patch Available, Release Note Needed]  (was: [Release Note Needed, Patch
Available])

looking at it more carefully, would it be possible to not have any sorter changes and handle
the required functionality in the
new UniqueWithDuplicateNullsIndexSortObserver ?  Basically use the existing sorter to sort
on all columns and then in the observer look at each row and if it has a null let it through.
 If it doesn't have a null compare it with the next row and throw an error if it has a duplicate
violation?   I know there is some existing code for doing this kind of compare - see 
CardinalityCounter.java.  



> provide support for unique constraint over keys that include one or more nullable columns.
> ------------------------------------------------------------------------------------------
>
>                 Key: DERBY-3330
>                 URL: https://issues.apache.org/jira/browse/DERBY-3330
>             Project: Derby
>          Issue Type: New Feature
>          Components: Store
>    Affects Versions: 10.4.0.0
>         Environment: all
>            Reporter: Anurag Shekhar
>            Assignee: Anurag Shekhar
>         Attachments: BTreeController.diff, db2Compatibility-v2.diff, db2Compatibility.diff,
derby-3330-testcase.diff, derby-3330-UpgradeTests.diff, derby-3330.diff, derby-3330_followup_1.diff,
derby-3330v10.diff, derby-3330v11.diff, derby-3330v12.diff, derby-3330v13.diff, derby-3330v2.diff,
derby-3330v3.diff, derby-3330v4.diff, derby-3330v5.diff, derby-3330v6.diff, derby-3330v7.diff,
derby-3330v8.diff, derby-3330v9.diff, derbyall_report.txt, FunctionalSpec_DERBY-3330-V2.html,
FunctionalSpec_DERBY-3330.html, UniqueConstraint_Implementation.html, UniqueConstraint_Implementation_V2.html,
UniqueConstraint_Implementation_V3.html, UniqueConstraint_Implementation_V4.html
>
>
> Allow unique constraint over keys which include one or more nullable fields.  Prior to
this change Derby only supported unique constraints on keys that included no nullable columns.
 The new constraint will allow unlimited inserts of any key with one more null columns, but
will limit insert of keys with no null columns to 1 unique value per table.
> There is no change to existing or newly created unique indexes on null columns (as opposed
to unique constraints on null columns).  Also there is no change to existing or newly created
constraints on keys with no nullable columns.

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