[
https://issues.apache.org/jira/browse/DERBY-3330?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Mike Matrigali updated DERBY-3330:
----------------------------------
comment on implementation details:
While creating the unique constraint null checking is now conditional (only for
the older version of Data Dictionary). In case of older version Data Dictionary
the backing index created is an unique index.
In order to not cause performance degredation for existing unique constraints I
would have expected the constraint creation code to use the old unique index
for non-null columns and use the new index for null columns. The unique
index is going to perform somewhat better as it will have less checking to do
(for instance on insert it will not have to
check if nulls are in the key and do extra searching). Also it will make it
likely that only new applications that use the new
feature will see any new problems introduced by the new index. Existing
applications will continue to use the old
code.
> provide support for unique constraint over 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, derby-3330-testcase.diff,
> derby-3330.diff, derby-3330v2.diff, derby-3330v3.diff, derby-3330v4.diff,
> derby-3330v5.diff, derby-3330v6.diff, derby-3330v7.diff, derby-3330v8.diff,
> FunctionalSpec_DERBY-3330-V2.html, FunctionalSpec_DERBY-3330.html,
> UniqueConstraint_Implementation.html
>
>
> Allow unique constraint over nullable field. Right now derby support unique
> constraint only over not null columns.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
