Description Jean-David Maillefer 2009-01-29 06:08:52 EST

Created attachment 124135 [details]
Patch of the changes I made

The @SequenceGenerator doesn't do what's expected for DB2:
DB2 supports both identity columns and native sequences. But the current implementation doesn't make the difference.

For example, the following code should work:
@Entity
@SequenceGenerator(initialValue=1,sequenceName="ENTREPRISE_SEQ",name="Entreprise_seq",allocationSize=1)
public class Entreprise implements Serializable {
  @Id
  @GeneratedValue(strategy=GenerationType.SEQUENCE,generator="Entreprise_seq")
  private Integer id;
  ...
}

But the current implementation ignores the sequence and assumes an identity column (as explained in the doc/wiki, the sequences are currently not fully implemented for DB other than Oracle). This causes problems of having the id field set to null (expecting the DB will auto-affect the IDENTITY column) instead of already set by the next value of the sequence.

I made a patch which works for us and suggest to include it in the next version.
(This small patch includes some coherency changes in comments + serialVersionUID, but you can ignore them if you want)

I point out that the SQL used in sequence generation I propose is ISO SQL 2003 compliant and could be used on other platform following this standard.
I didn't found in the current API the way to specify finer grained properties of sequences other than "increment by". According to ISO SQL 2003, the following additional options should be available: data type, start with, maxvalue, minvalue and cycle.