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From "Patrick Linskey" <plins...@bea.com>
Subject RE: AW: Using @GeneratedValue for IDs on already existing tables
Date Tue, 13 Feb 2007 17:12:38 GMT
> I can remember a legacy persistence framework that was able to retry
> the insert statement with a "second-try generated PK" just 
> for the case
> the currently generated one has already been inserted by 
> another process.

It would certainly be possible to implement such a thing in OpenJPA, but there is no such
feature in place currently.

If you're decommissioning the old system, one easy way to make things work would be to use
a hi-lo table with per-class entries (the class-table alias), and then manually configure
the start value in the table (using the main() method in the org.apache.openjpa.jdbc.kernel.ClassTableJDBCSeq)
to be the highest existing PK value for each table.

-Patrick

-- 
Patrick Linskey
BEA Systems, Inc. 

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> -----Original Message-----
> From: Hans J. Prueller [mailto:hans.prueller@gmx.net] 
> Sent: Tuesday, February 13, 2007 9:01 AM
> To: open-jpa-dev@incubator.apache.org
> Subject: AW: AW: Using @GeneratedValue for IDs on already 
> existing tables
> 
> thanks for this link but this section only describes the different
> algorithms that are provided to get the generated value - it does
> not mention the case what happens if we try to save a new persistent
> entity with a generated PK value that already exists in the DB?
> 
> I can remember a legacy persistence framework that was able to retry
> the insert statement with a "second-try generated PK" just 
> for the case
> the currently generated one has already been inserted by 
> another process.
> 
> does nobody else have a similar requirement?
> 
> hans
> 
> > -----Urspr√ľngliche Nachricht-----
> > Von: Abe White [mailto:awhite@bea.com]
> > Gesendet: Dienstag, 13. Februar 2007 17:35
> > An: open-jpa-dev@incubator.apache.org
> > Betreff: Re: AW: Using @GeneratedValue for IDs on already 
> existing tables
> > 
> > > does openJPA provide the strategy to re-generate another value for
> > > the PK
> > > or do we have to manually deal with this case?
> > 
> > http://incubator.apache.org/openjpa/docs/latest/manual/
> > manual.html#ref_guide_sequence
> > 
> ______________________________________________________________
> _________
> > Notice:  This email message, together with any attachments, 
> may contain
> > information  of  BEA Systems,  Inc.,  its subsidiaries  and 
>  affiliated
> > entities,  that may be confidential,  proprietary,  
> copyrighted  and/or
> > legally privileged, and is intended solely for the use of 
> the individual
> > or entity named in this message. If you are not the 
> intended recipient,
> > and have received this message in error, please immediately 
> return this
> > by email and then delete it.
> 
> 

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