openjpa-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Christoph Ewerlin (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (OPENJPA-1066) Generated ID starting with 0 can cause unexpected results
Date Mon, 10 Mar 2014 08:16:43 GMT

    [ https://issues.apache.org/jira/browse/OPENJPA-1066?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13925542#comment-13925542
] 

Christoph Ewerlin commented on OPENJPA-1066:
--------------------------------------------

GENERATED BY DEFAULT AS IDENTITY (START WITH 1...) works for us.
Please update the respective data base dictionaries so that during schema auto-creation tables
are generated with IDs not starting at 0.
We encounter the issue with org.apache.openjpa.jdbc.sql.HSQLDictionary


> Generated ID starting with 0 can cause unexpected results
> ---------------------------------------------------------
>
>                 Key: OPENJPA-1066
>                 URL: https://issues.apache.org/jira/browse/OPENJPA-1066
>             Project: OpenJPA
>          Issue Type: Improvement
>          Components: kernel
>    Affects Versions: 2.2.0
>         Environment: any DB that allows a generated id to start with 0.  And an entity
that maps that generated id to an int instead of an Integer
>            Reporter: B.J. Reed
>            Priority: Minor
>         Attachments: GeneratedIDStartsWith0.ZIP
>
>
> Several DB's allow a generated id column to start with 0.
> For instance, DB2 allows  "GENERATED ALWAYS AS IDENTITY (START WITH 0)...."
> When this is used, the very first object will have an id of 0.  When entities are first
created, the user usually won't fill in the corresponding id field (since it will be generated
by the DB when the entity is put in the DB), so it defaults to 0.  The entity manager then
uses this 0 and sees that an entity already exists and will update the old entity in stead
of creating a new one.
> This is not a large issue, because a user could simply specify "START WITH 1" as a very
simple workaround or they could use an Integer instead of an int, but it would be nice to
fix so that new users don't hit this problem.



--
This message was sent by Atlassian JIRA
(v6.2#6252)

Mime
View raw message