Hallo all, i'm pretty new.

I got a problem with Hibernate.

I got a Pojo like this one

public class Argument {
private String id;
private String key;
private String value;

......
}

In hibernate mapping the id is native.

I would like the same record in the DB when i save two Arguments with same key and value.

Instead when a create two arguments like in this code:

Argument argument = new Argument(key1, value1);
Argument argument1 = new Argument(key1, value1);

..... session.saveOrUpdate(argument);
..... session.saveOrUpdate(argument1;

I get two different records in the table Argument like this

ID KEY VALUE
1 key1 value1
2 key1 value1


Is it possible to make something like this?

Thank yuo very much.

Massimo

then you should consider to define your
private String key;
private String value;
as primary key.

Read about composite-id
and natural primary key in the reference.

When these fields become your primary keys you cannot change them using Hibernate any more.

If you want to be able to change them, you must stick to your id
and verify by your application that it first tries to find an existing Argument with your keys before inserting a new one.

Regards Sebastian

Thank you for your reply.

So the problem is thata Argument is in association N:1 with a bean named Agent in this way:
Agent N <--------- 1 Argument

So every Agent has a

Collection<Argument> argument = new HashSet<Argument>();

to express this association.

Since i parse data from xml with Digester, every Agent Collection wil have different instances of the same semantic Argument.

Is the only way to process "by hand" every Collections and to fix the problem
coding a method that searches for every instance of same semantic Argument replacing all of them with the same?

Thank you again.

By bY

Massimo

If you want to avoid making a db select for each argument than you might add each argument to a HashMap during parsing. Calculate the hash from your two fields and look in the HashMap if the entry exists.



You can keep your id in this case but must make sure that your calculateHash method does only take the two fields into account.

I would appreciate, if you help, when this helps.

Regards Sebastian

Ok thank you, i appreciated your post and i rated them.

I also make a post of your guides to delicious :D

By by all

Massimo