How to limit a collection in an Object's property in hibernate?

Question

I have two entities: item, and bid, each item have many bids for it, so bid is a collection property of item.

in the page that show an item, I just want to show the firs

Answer 1

This works so much better if you also have an association from Bid to Item.

Then you can select the items and apply the limit restriction:

session
    .createQuery(
    "select b
    from bid b
    join fetch b.item i
    where 
        i.id=3")
    .setMaxResult(10)
    .list();

Your previous query, the one selecting Item and fetching Bids will always select all items with all their bids and apply the max result limit in-memory. This is because Hibernate must always fetch all children, it can't give you partial collection results.

Selecting the child and joining the parent is a better alternative. The restriction applies to the selected children with no restriction whatsoever.