Guy Rouillier wrote:
> On 2/20/2010 3:21 PM, Jakub Vondrak wrote:
>> Hello,
>>
>> I'm new to iBatis 3 so maybe I'm overooking something obvious, but I'm
>> having problem while trying to map id object as association.
>>
>> Here is my result map
>>
>> <resultMap id="billResultMap" type="Bill">
>> <id column="bill_id" property="id" />
>> <collection property="billItems" ofType="BillItem">
>> <result column="bi_sku" property="customId" />
>> <result column="bi_name" property="name" />
>> ...
>>
>> <association property="id" javaType="BillItemId">
>> <id column="bill_id" property="idBill"/>
>> <id column="bill_id" property="itemOrder" />
>> </association>
>> </collection>
>> </resultMap>
>>
>> Problem is that class BillItem has another class BillItemId which acts
>> as ID, but I'm not able to express this fact in result map.
>> This is probably the reason why I'm having performance problems
>> (java.lang.OutOfMemoryError: Java heap space).
>>
>
> That's not a performance problem, that's an out-of-memory problem. You
> probably have a circular reference. Take a look in the User Guide PDF
> in the section titled Advanced Result Mapping. It has an example using
> an association. An association is a 1-to-1 mapping. Your example above
> doesn't identify a column on which to establish the association. It
> also lists two <id> entries, both for the same source column. That
> can't be right.
>
Thanks for the answer. If I reduce returned record count, I don't get
OutOfMemory, but I'm still not able to do what I need in mapping and I
guess that OutOfMemory exception is related to it.
First let me give you more information:
DB schema looks like this:
CREATE TABLE BILL(
ID INTEGER NOT NULL PRIMARY KEY
)
CREATE TABLE BILL_ITEM(
ID_BILL INTEGER NOT NULL,
ITEM_ORDER INTEGER NOT NULL,
SKU VARCHAR(255),
NAME VARCHAR(255),
PRIMARY KEY(ID_BILL,ITEM_ORDER),
CONSTRAINT BILL FOREIGN KEY(ID_BILL) REFERENCES BILL(ID)
)
Mapping for select looks like this:
<select id="selectAll" resultMap="billResultMap">
select
B.id as bill_id,
BI.item_order as bi_item_order,
BI.sku as bi_sku,
BI.name as bi_name,
from bill B
left outer join bill_item BI on B.id = BI.id_bill
</select>
What I guess is the problem is that I cannot express *composite key as
an BillItemId object* on the BillItem class and I guess I will need own
TypeHandler for whole Bill class.
I was expecting, that something like:
<id property="id" column="{idBill=bill_id, itemOrder=bi_item_order}"
javaType="BillItemId"/>
is possible, but it doesn't seem so.
Every combination I have tried yields following errors:
1) there is just one BillItem for each Bill
2) BillItemId for every BillItem is null
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