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From "Jeff Levitt (JIRA)" <derby-...@db.apache.org>
Subject [jira] Commented: (DERBY-382) Doc Review (CLOSED TO FURTHER COMMENTS): Derby Reference Manual
Date Wed, 29 Jun 2005 23:59:58 GMT
    [ http://issues.apache.org/jira/browse/DERBY-382?page=comments#action_12314720 ] 

Jeff Levitt commented on DERBY-382:
-----------------------------------

Adding Kathey Marsden's comment on Derby-275 that was added after that issue was committed:

 REGARDING THIS PARAGRAPH:

Note that unlike a GENERATED ALWAYS column, a GENERATED BY DEFAULT column does not guarantee
uniqueness. Thus, in the above example, the hi and salut rows will both have an identity value
of "1", because the generated column starts at "1" and the user-specified value was also "1".
To prevent this, you can use the "STARTS WITH" keyword described below. To check for this
condition and disallow it, you can use a primary key or unique constraint on the GENERATED
BY DEFAULT identity column.

In the paragraph STARTS WITH should be START WITH and loading or importing data should be
covered.

CHANGE:
To prevent this, you can use the "STARTS WITH" keyword described below.

TO:

To prevent duplication especially when loading or importing data, create the table using a
"START WITH" value which corresponds to the first
identity value that the system should assign.

ADD AN EXAMPLE:

create table greetings
        (i int generated by default as identity (START WITH 2, INCREMENT BY 1),
 ch char(50));
-- specify value "1":
insert into greetings values (1, 'hi');
-- use generated default
insert into greetings values (DEFAULT, 'salut');
-- use generated default
insert into greetings(ch) values ('bonjour'); 

> Doc Review (CLOSED TO FURTHER COMMENTS): Derby Reference Manual
> ---------------------------------------------------------------
>
>          Key: DERBY-382
>          URL: http://issues.apache.org/jira/browse/DERBY-382
>      Project: Derby
>         Type: Improvement
>   Components: Documentation
>  Environment: all
>     Reporter: Jeff Levitt
>     Priority: Minor
>      Fix For: 10.1.1.0

>
> This issue tracks comments for the Derby Reference Manual. The deadline for posting comments
was Tuesday, June 28, noon Pacific time.
> PLEASE DO NOT POST ADDITIONAL COMMENTS TO THIS JIRA ISSUE.  If you have additional comments,
please open a JIRA issue for a fixin in a future release, as there is not enough time to incorporate
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> Some guidelines to follow when posting comments to this issue are:
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