Re: [ojb-users] Re: Error in 1:n mapping using ODMG API

[Thomas M. <tho...@ho...>]

Hi all,

Lorenzo Nicora wrote:

> I hope this is not a FAQ :-)
> 


unfortunately it is!

As mentioned in tutorial3.html#cascading

YOU MUST NOT SET auto-update to true in an ODMG implementation.
The ODMG has its own mechanism to do cascading operations!

Thomas


> 
>>From: "Govindarajan S (Gover)" <gov...@az...>
>>To: obj...@li...
>>Date: Wed, 5 Jun 2002 18:58:37 +0530
>>Subject: [ojb-users] Error in 1:n mapping using ODMG API
>>
> 
> Hello,
> 
> 
>>I get the following exception when using the ODMG API for persisting
>>the 1:n mapping. I have a product group class which has a collection
>>of articles. Iam trying to persist the ProductGroup. As expected it
>>tries to persist the Article as well. But during the process i get the
>>following exception message,
>>
>>[ojb.broker.singlevm.PersistenceBrokerImpl] ERROR: Error in
>>Transaction abort: General error: Warning:  Some non-transactional
>>changed tables couldn't be rolled back
>>org.odmg.TransactionAbortedException: Invalid argument value:
>>Duplicate entry '71' for key 1
>>[...]
>>
> 
>>From what i observed its trying to insert the article, which is
>>already inserted. I took a look at the SQL queries submitted to the
>>database and found this,
>>[...]
>>At this stage an SQLException is thrown.
>>
>>What could be going wrong? why is it trying to insert the first
>>element again?
>>
> 
> 
> I'm experiencing a similar problem, persinsting the classic 1:n 
> mapping: 1 Order to n. tems
> (using OJB v.0.9)
> 
> I made the association navigable in both directions: 
> in Order there is a collection of Items AND in the Item there is the 
> FK to Order + the reference to the Order
> Both tables PK are autoincrements.
> 
> If I set the collection of Items in Order for auto-update, when I insert 
> a new Order (with new Items), OJB tries to insert duplicate Items 
> (with the same PK) causing the exception.
> Setting "auto-update" to false eliminates the problem! ( sadly, the 
> auto-update feature could be useful :-( )
> 
> Here is the (very simplified) classes code:
> ----------------------------------------------------------
> public class Order 
> {
> 	private int id;
> 	private Vector items;
> 	[...]
> }
> 
> public class Item
> {
> 	private int id;
> 	private int orderId;
> 	private Order order;
> 	[...]
> }
> ----------------------------------------------------------
> 
> And the (very simplified) mapping is this:
> ----------------------------------------------------------
> <class-descriptor class="test.Order" table="_Orders">
>       <field-descriptor id="1"
>          name="id"
>          column="id"
>          jdbc-type="INTEGER"
>          primarykey="true"
>          autoincrement="true"
>       />
> 	[...]
>       <collection-descriptor name="items" 
> 	    element-class-ref="test.Item"
>          auto-retrieve="true" auto-update="true" auto-delete="false"
>       >
>          <inverse-foreignkey field-id-ref="3"/>
>       </collection-descriptor>	  
> </class-descriptor>
> 
> <class-descriptor class="test.Item" table="_Items">
>       <field-descriptor id="1"
>          name="id"
>          column="id"
>          jdbc-type="INTEGER"
>          primarykey="true"
>          autoincrement="true"
>       />
>      [...]
>       <field-descriptor id="3"
>          name="orderId"
>          column="orderId"
>          jdbc-type="INTEGER"
>       />
>       <reference-descriptor name="order"
>          class-ref="test.Order"
>       >
>          <foreignkey field-id-ref="3"/>
>       </reference-descriptor>
> </class-descriptor>
> ----------------------------------------------------------
> [I removed fileds and references that doesn't have anything to do 
> with the problem]
> 
> THIS mapping will cause the problem inserting a new Order. 
> Changing "auto-update" to "false", in the "collection-descriptor", will 
> not.
> 
> Is is an OJB problem? 
> Or is it a logic problem in the mapping?
> 
> Bye
> 	Lorenzo
> 
> 
> 
> 
> 
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