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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 Tue, 04 Mar 2008 17:49:42 GMT

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

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

    Description: 
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.


  was:Allow unique constraint over nullable field. Right now derby support unique constraint
only over not null columns.

     Derby Info: [Patch Available, Release Note Needed]  (was: [Release Note Needed, Patch
Available])
        Summary: provide support for unique constraint over keys that include one or more
nullable columns.  (was: provide support for unique constraint over nullable columns)

revision 633560 checked into trunk:

DERBY-3330
committed on behalf of Anurag Shekhar

Committed modified versions of patch derby-3330v13.diff and
db2Compatibility-v2.diff.  The modifications are mostly changed and/or
added comments along with some code formatting changes to make the
new code match the surrounding code style.

This checkin adds the functionality to
create unique constraints on a key that contains one or more nullable
columns.  This constraint will all inserts of all keys that contain
one or more columns with the null value.  All keys that contain no columns
with null values are constrained to be unique in the table.

The underlying implementation for this new type of unique constraint uses
the existing btree non-unique index with a small modification to do
checking at insert time to provide the described unique behavior for null
and non-null keys.  The sorter has also been modified to provide this
support for creating the index.

> 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.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
>
>
> 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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