Optimizing fetching with Hibernate - How do I get my ID?

[Darya Akbari]

Hi,

One topic of Hibernate is to minimize the database hits when working with Hibernate and a domain model (POJOs). Hence Hibernate uses proxies based on the Hibenate Mappings instead of the real entity.

Look the next example from the book Java Persistence with Hibernate p.565:

    
Item item = (Item) session.load(Item.class, new Long(123));
User user = (User) session.load(User.class, new Long(1234));
Bid newBid = new Bid("99.99");
 
newBid.setItem(item);
newBid.setBidder(user);
session.save(newBid);

The only database hit (INSERT) is at the last line in above example when doing save.

But where do I get my ID's (123, 1234) from? Wouldn't it be through a another database hit (SELECT) .

Aren't there other solutions for obtaining the IDs w/o touching the database? I mean at some point one had to insert Item(123) and Bid(1234).

Regards,
Darya
[ September 12, 2007: Message edited by: Darya Akbari ]