[jboss-user] [JBoss Seam] - Re: How to use @Id @GeneratedValue(strategy=GenerationType.A

trickyvail do-not-reply at jboss.com
Thu Mar 1 13:26:21 EST 2007

In Enterprise JavaBeans 3.0 (O'Reilly 2006) it states "The AUTO strategy tells the persistence provider that you are allowing it to generate the key for you" (page 94).

I don't specifically know the Hibernate implements this feature, but might I suggest that you utilize the features of your database to create primary keys instead.

With Postgresql you could use a mapping like this:

  | 	@Column(name = "id", unique = true, nullable = false)
  | 	@SequenceGenerator(name="identifier", sequenceName="ppl_id_seq", allocationSize=1)
  | 	@GeneratedValue(strategy=GenerationType.SEQUENCE, generator="identifier")
  | 	@NotNull
  | 	public int getId()
  | 	{
  | 		return this.id;
  | 	}

In this manner Hibernate would assign primary keys from the Postgresql sequence rather than internally. This would allow Hibernate to "play nicely" with other database users.

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