Hi,

I try to implement an order in a webshop.
Therefore i have an relation Orders, an relation orderpositions and an
relation article.
The table orderpositions has the columns: artnr(Foreign key. PK in article),
ordnr(Foreign key. PK in Orders), posnr(Primary key) and quantity.
The ordnr is an autogenerated value(in Orders).

When I try to persist an Order (entitymanager.persist(order)), hibernate should
persist the positions automatically at the same transaction(cascade={Persist}).

The Problem is, when hibernate is trying to persist the positions it has
a null value at ordnr.
But I think he should automatically take the new generated Value from Oders.

The Errormsg:

Caused by: java.sql.BatchUpdateException: Batch-Eintrag 0 insert into postgres.orderpositions (quantity, artnr, ordnr, posnr) values (1, 51, NULL, 15) was cancelled.

Mapping:

orderpositions:

@ManyToOne
@JoinColumn(name="ordnr")
private Order order;

@ManyToOne
@JoinColumn(name="artnr")
private Article article;

Orders:

@OneToMany(mappedBy="order",cascade={ALL})
private List<orderpositions> orderpositionsCollection = new ArrayList<orderpositions>();

Can anyone help me ??

Thanks.

Without seeing your code it is not obvious what is going wrong but remember that while in the database a foreign key is a two way association in your Java model it is not. This means simply adding an OrderPosition object to the list associated with an order is not enough. You also have to set the Order on the OrderPosition. This is typically referred to as needing 'scaffolding' code to maintain two way relations ships.

So try this in your Order class unless you do it already:

Hi malm66,

Thank you so much, it works fine!!

Bye