Sorry, I assumed you understand the Castor JDO model.
In Castor JDO,
All reachable data objects must be loaded/queried/created
within the same transaction.
If you intended to use some object load/queried/create from
any prior transaction, it is called long transaction. Each of
those objects should be update() to the current transaction
before it is linked any object in this transaction.
Thomas
-----Original Message-----
>From: Bernecker Lothar [mailto:[EMAIL PROTECTED]]
>Sent: Monday, February 04, 2002 2:15 AM
>To: [EMAIL PROTECTED]
>Subject: Re: [castor-dev] NULL value is inserted instead of key value
>
>
>First of all I'd like to apologize for having asked a question which
>has obviously been asked before.
>I tried all the things described in the message below but I still have the
>same problem.
>I do not want to create a new Product with creating an Order
>(which implicitly creates OrderItems which worked fine from the beginning).
>I just want to store a reference to the Product in OrderItem (At least
>that's what
>I tried to express with my mapping file).
>
>When I use bi-direction nothing changes at all, productid is
>still NULL.
>When I use setAutoCommit(true) a new Product is created for
>each stored Order (which is not the desired behaviour).
>
>The only thing which helped so far is to remove the key-generator attribute
>from the mapping of class Product. Then it works fine for this part of
>my application. Of course, then creating Products in another part of the
>application does not work unless I generate the key for a Product by
myself.
>
>Another solution I found is to implement the Persistent interface in
>OrderItem
>and add the code
>
> product_ = (Product) db.load(Product.class, product_.getId());
>
>to jdoBeforeCreate().
>
>But I still do not understand why I either have to remove the key-generator
>or have to reload the Product object. Currently I think these solutions are
>workarounds which I need because I did something wrong.
>If anyone could help me further to find out what I did wrong or explain why
>it is working only with the solutions described above, I would be very
>thankful.
>
>Kind regards,
>
>Lothar
>
>
>
>-----Ursprüngliche Nachricht-----
>Von: Thomas Yip [mailto:[EMAIL PROTECTED]]
>Gesendet: Donnerstag, 31. Januar 2002 20:39
>An: [EMAIL PROTECTED]
>Betreff: Re: [castor-dev] NULL value is inserted instead of key value
>
>
>
>I think it question has been risen many times. But, each user use
>description differently and nobody ever think they're the same problem.
>
>Normally, the NULL is inserted, either because your relationship is
>uni-direction. And, uni-direction is not supported. In other words,
>make a back reference is a must.
>
>On the other hand, you need to synchronize the bi-direction yourself.
>Meaning that you must do it in your code:
>class foo {
> void setBar( Bar bar ) {
> if ( bar != null )
> bar.setFoo( this );
> }
>}
>
>The third reason is for non-dependent object.
>a) you didn't setAutoStore( true ),
>b) and you didn't explicitly create the second object,
>before explicitly the first one.
>In other word, you either do (a) or (b), but not both.
>
>
>
>Thomas
>
>
>(PS. I will try break the update(...) hack if I know why it works,
>but I still don't understand why it would.)
>
>-----Original Message-----
>>From: Ricardo Argüello [mailto:[EMAIL PROTECTED]]
>>Sent: Thursday, January 31, 2002 10:35 AM
>>To: [EMAIL PROTECTED]
>>Subject: Re: [castor-dev] NULL value is inserted instead of key value
>>
>>Hello,
>>
>>Would somebody write an authoritative answer on what is the CORRECT
>solution?
>>
>>It looks like there is no concense on what is the "propper way" to use
>Castor.
>>
>>Somebody comes up with a "hack" to make it act the intended way, another
>one has yet nother "hack", but there is not a "propper way" in the docs, or
>in the website, or in the CVS!
>>
>>Castor looks like Perl: "There is more than one way to do it". That is Not
>Good (TM).
>>
>>Thanks.
>>
>>
>>----- Original Message -----
>>From: "Peter T. Brown" <[EMAIL PROTECTED]>
>>To: <[EMAIL PROTECTED]>
>>Sent: Thursday, January 31, 2002 1:14 PM
>>Subject: Re: [castor-dev] NULL value is inserted instead of key value
>>
>>
>>> I have had this same problem.. I could never find a 'correct' solution,
>so
>>> have resorted to calling update() on the related collection. So in your
>>> example below I would add update(item) before committing the
transaction.
>>> This seems to force castor to work properly.
>>>
>>> Peter
>>>
>>> -----Original Message-----
>>> From: Bernecker Lothar [mailto:[EMAIL PROTECTED]]
>>> Sent: Thursday, January 31, 2002 1:08 AM
>>> To: [EMAIL PROTECTED]
>>> Subject: [castor-dev] NULL value is inserted instead of key value
>>>
>>>
>>> Hi,
>>>
>>> I have the problem that a NULL is entered into my table instead of the
>value
>>> of the foreign key.
>>> I have the following mapping specified:
>>>
>>> <mapping>
>>> <class name="cat.Product" identity="id" key-generator="Unique">
>>> <description>Product definition</description>
>>> <map-to table="product" />
>>> <field name="id" type="string">
>>> <sql name="id" type="varchar" />
>>> </field>
>>> <field name="name" type="string">
>>> <sql name="name" type="char" />
>>> </field>
>>> </class>
>>>
>>> <class name="cat.Order" identity="id" key-generator="Unique">
>>> <description>An order</description>
>>> <map-to table="orders" />
>>> <field name="id" type="string">
>>> <sql name="id" type="varchar" />
>>> </field>
>>> <field name="orderDate" type="date">
>>> <sql name="orderdate" type="date" />
>>> </field>
>>> <field name="orderItems" type="castortest.OrderItem"
>required="true"
>>> collection="collection">
>>> <sql many-key="orderid"/>
>>> </field>
>>> </class>
>>>
>>> <class name="cat.OrderItem" identity="id" depends="castortest.Order"
>>> key-generator="Unique">
>>> <description>An order</description>
>>> <map-to table="orderitem" />
>>> <field name="id" type="string">
>>> <sql name="id" type="varchar" />
>>> </field>
>>> <field name="product" type="castortest.Product">
>>> <sql name="productid" />
>>> </field>
>>> <field name="quantity" type="integer">
>>> <sql name="quantity" type="integer" />
>>> </field>
>>> <field name="order" type="castortest.Order">
>>> <sql name="orderid" />
>>> </field>
>>> </class>
>>>
>>> <key-generator name="UUID" alias="Unique"/>
>>>
>>> </mapping>
>>>
>>> When I use the following sequence to create a new order then the
>productid
>>> column in order item
>>> is always NULL:
>>>
>>> Product p = null;
>>> .
>>> .
>>> db = jdo.getDatabase();
>>>
>>> db.begin();
>>>
>>> query = db.getOQLQuery(oql);
>>> qr = query.execute();
>>>
>>> if (qr.hasMore()) {
>>> p = (Product) qr.next();
>>> }
>>>
>>> db.commit();
>>>
>>> db.begin();
>>>
>>> Order order = new Order();
>>> OrderItem item = new OrderItem();
>>> item.setOrder(order);
>>> item.setProduct(p);
>>> item.setQuantity(1);
>>> order.addOrderItem(item);
>>>
>>> db.create(order);
>>>
>>> db.commit();
>>> db.close();
>>>
>>> The strange this is that this only happens when I use a key-generator
for
>>> Product. When I remove
>>> the key-generator attribute then it works fine in this context. Can
>anyone
>>> tell me what I did wrong?
>>>
>>> Kind regards,
>>>
>>> Lothar
>>>
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>>
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