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From "Bryan Pendleton (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DERBY-6904) Enhance ALTER TABLE to allow CYCLE option to be changed.
Date Mon, 13 Mar 2017 13:59:41 GMT

    [ https://issues.apache.org/jira/browse/DERBY-6904?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15907498#comment-15907498

Bryan Pendleton commented on DERBY-6904:

Thanks for all the work on this!

I shall try to find some time to download your patches and see if I can observe the same results
that you do.

There is an upgrade process in Derby, and I agree with you that it seems like it is not succeeding
to upgrade the database properly to be aware of the changed columns in SYSCOLUMNS.

I shall have to do some study to understand why the upgrade isn't occurring as you expect.
The upgrade is supposed to be automatic based on the version number of the database, but perhaps
there is an upgrade function that we will need to code to make the change to SYSCOLUMNS.

Or it may be more delicate because SYSCOLUMNS is a particularly sensitive core table.

I suppose, as an experiment, you could back out just the SYSCOLUMNS portion of your patch,
leaving all the other aspects in place, and see how the various test suites behavior in that

> Enhance ALTER TABLE to allow CYCLE option to be changed.
> --------------------------------------------------------
>                 Key: DERBY-6904
>                 URL: https://issues.apache.org/jira/browse/DERBY-6904
>             Project: Derby
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions:
>            Reporter: Bryan Pendleton
>            Priority: Minor
>         Attachments: 6904.diff, columnMismatch, compareDbName
> It would be nice to have a variant of the ALTER TABLE statement,
> similar to the SET INCREMENT BY or SET RESTART WITH variants,
> that allowed a user to change the CYCLE option on an IDENTITY column.
> I think that the code flow for this could be closely modelled on the
> code flow for the SET INCREMENT BY variant: after the statement
> is parsed, we simply need to drop and recreate the underlying SEQUENCE
> object with the desired CYCLE option (and preserving all the other
> aspects of the underlying SEQUENCE object.

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