Hi folks,

Hibernate version: 3.2

Tried to make the following simple idbag mapping:

<class name="Account" table="ACCOUNT">
<id name="id" column="ID_ACCOUNT">
<generator class="native"/>
</id>
<property name="code"
type="string"
length="10"
not-null="true"
unique="true"
/>

<idbag name="statements" table="STATEMENT" >
<collection-id type="long" column="ID_STATEMENT">
<generator class="sequence" />
</collection-id >
<key column="ID_ACCOUNT" not-null="true"/>
<composite-element class="Statement">
<parent name="account" />
<property name="date" type="timestamp" not-null="true" />
<property name="amount" type="double" not-null="true" />
<property name="description" type="string" length="100" />
</composite-element>
</idbag>
</class>

and then used the following code to check:
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Session s1 = me.getCurrentSession();
s1.beginTransaction();

Account a = new Account("001");
a.addStatement(new Statement(new Date(), 10, "first"));
a.addStatement(new Statement(new Date(), -9, "second"));
Long aid = (Long) s1.save(a);

s1.getTransaction().commit();
me.log("fresh session");

Session s2 = me.getCurrentSession();
s2.beginTransaction();

Account a1 = (Account) s2.get(Account.class, aid);
me.log("stmts" + a1.getStatements());

s2.getTransaction().commit();
------------------------------------------------------
I noticed that even in case of using <collection-id> element,
the idbag always tries to remove ALL collection elements
from database and the re-insert them even without ANY modification.
Which is strange. Here is the output:
------------------------------------------------------
Hibernate: insert into V1.ACCOUNT (ID_ACCOUNT, code) values (default, ?)
Hibernate: values identity_val_local()
Hibernate: values nextval for V1.hibernate_sequence
Hibernate: values nextval for V1.hibernate_sequence
Hibernate: insert into V1.STATEMENT (ID_ACCOUNT, ID_STATEMENT, date, amount, description) values (?, ?, ?, ?, ?)
Hibernate: insert into V1.STATEMENT (ID_ACCOUNT, ID_STATEMENT, date, amount, description) values (?, ?, ?, ?, ?)
###main: fresh session
Hibernate: select account0_.ID_ACCOUNT as ID1_3_0_, account0_.code as code3_0_ from V1.ACCOUNT account0_ where account0_.ID_ACCOUNT=?
Hibernate: select statements0_.ID_ACCOUNT as ID1_0_, statements0_.date as date0_, statements0_.amount as amount0_, statements0_.description as descript4_0_, statements0_.ID_STATEMENT as ID5_0_ from V1.STATEMENT statements0_ where statements0_.ID_ACCOUNT=?
###main: stmtsorg.hibernate.collection.PersistentIdentifierBag@66ce66ce
Hibernate: delete from V1.STATEMENT where ID_ACCOUNT=?
Hibernate: values nextval for V1.hibernate_sequence
Hibernate: values nextval for V1.hibernate_sequence
Hibernate: insert into V1.STATEMENT (ID_ACCOUNT, ID_STATEMENT, date, amount, description) values (?, ?, ?, ?, ?)
Hibernate: insert into V1.STATEMENT (ID_ACCOUNT, ID_STATEMENT, date, amount, description) values (?, ?, ?, ?, ?)
###main: *** STOP ***
------------------------------------------------------

Can anyone explain me why this happens ?

Regards,
/Alexander