Question

I have a strange Hibernate behaviour in my program.
I have two classes with onetomany relation: good and price:

    @Entity
    @Table(name="GOODS")
    public class Good {

    ....
    @OneToMany(cascade=CascadeType.ALL, fetch=FetchType.EAGER)
    @JoinColumn(name="GOOD_ID")
    private Set<Price> prices = new HashSet<Price>();
    ...}



    @Entity
    @Table(name="PRICES")
    public class AuctionPrice {

    ..

    @Column(name="PRICE")
    private double price;
    ...}

When I update hierarchial structure which contains goods I see such queries in hibernate sql log:

update PRICES set GOOD_ID=null where GOOD_ID=?
...
update PRICES set GOOD_ID=? where id=?

for all prices (when there are no actual changes in prices).

Why hibernate set this field to null and after it reverts it back, is it possible to avoid this?

Answer 1

If GOOD_ID can not be null (which I assume), you should declare it so:

@JoinColumn(name="GOOD_ID", nullable = false)