[hibernate-users] postgres @GeneratedValue

[Christine Karman]

We're having an issue with generated primary keys in a postgres 
database. We use Seam, JbossAS, JPA, Hibernate. In a class named Address 
we have a "long id" with the following annotations:

@Id
@SequenceGenerator(name = "ADDRESS_SEQ", sequenceName = 
"address_id_seq", allocationSize = 1, initialValue =51)
@GeneratedValue(generator = "ADDRESS_SEQ")
private long id;

This works perfectly well, until we decided to seed the database with an 
import script. It seems like Hibernate does not see the imported 
addresses. The address class in Postgres has a field 'id' of type 
"BigInt". But in order to have autogenerated keys, it should be 'serial'.

Our solution was to change the annotations to

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;

Now, I'm happy that we found a solution, but I don't understand why this 
works. Also, shouldn't Hibernate always make @GeneratedValue fields of 
type 'serial'?

 From what I found googling, this seems to be a problem that only occurs 
when you use Postgres.

dagdag
Christine



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