GenerationType.AUTO gives 1 sequence for all tables

jim_panse · **Joined:** Tue Apr 29, 2008 3:02 am **Posts:** 5

Hibernate version: 3.2.6.GA
Mapping documents:none -> using Annotations
Code between sessionFactory.openSession() and session.close():everything fine here
Full stack trace of any exception that occurs:no error no exception
Name and version of the database you are using:PostgreSQL 8.3

I have a small test project in Hibernate to learn the basics. I make use of Annotations and i want to autogenerate the ids of 4 tables with:

Code:

@GeneratedValue(strategy=GenerationType.AUTO)

That works fine in MySQL but creates only 1 sequence in PostgreSQL with the following effect:

enter object1 of type 1 --> ID 1
enter object2 of type 2 --> ID 2 (and not 1 as expected)
enter object3 of type 3 --> ID 3 (and not 1 as expected)
enter object4 of type 1 --> ID 4 (instead of 2)

I also tried own sequence generators which worked fine for Postgre but didn't work in MySQL (since there are no sequences in MySQL). I want to keep the whole project as generic as possible. Are there any tricks for using the

Quote:

GenerationType.AUTO

with PostgreSQL

Thx in advance[/b]

sagimann · **Joined:** Sun Jun 11, 2006 10:41 am **Posts:** 164

Try investigating GenetationType.TABLE?
Also, maybe the examples in the following URL will prove useful:

http://edocs.bea.com/kodo/docs41/full/html/ejb3_overview_mapping_sequence.html

jim_panse · **Joined:** Tue Apr 29, 2008 3:02 am **Posts:** 5

Hi sagimann,

i changed to

Code:

GenerationType.TABLE

and it works fine with both databases.
Is it possible to force Hibernate to pick up the next value after a server restart?
Right now he grabs a number starting at +50 or less.
lastID 3 -> restart -> nextID 50
lastID 86 -> restart -> nextID 100
lastID 101 -> restart -> nextID 150
This is not really a problem. I'm just curious whether it is possible.

Thx a lot already for the tip.
What i've seen so far is really cool. Hibernate rocks!!!

sagimann · **Joined:** Sun Jun 11, 2006 10:41 am **Posts:** 164

try changing allocation-size, which defaults to 50 I think.

jim_panse · **Joined:** Tue Apr 29, 2008 3:02 am **Posts:** 5

That worked like a charm. Thanks a lot again. Is there a special reason why it is set to 50 initially?

Greetings

sagimann · **Joined:** Sun Jun 11, 2006 10:41 am **Posts:** 164

Not sure. For me, it's just a good indication that the server went down (in case it was unexpected), although there are usually far better indications like logs, etc.