Hello All,

I have to design a mapping where two properties combined together are unique. I cannot use a composite-id for this as the primary key is self generated.

I have noticed a tag called composite-element, but it says that I have to use components for it. I am not sure if I want to use that.

Basically from the main frame system, the B2B system gets a XML file pertaining to a order. Now the order may consist of multiple items and each item is associated with a line number. Now in the mapping for a item, I want to describe that item together with the order id form a composite unique property.

What should/can I use to acheive the above functionality? This might sound something primitive, but please note that I am a beginner and am not an expert in DBAdministration.

Thanks,

Alpha.

Any thoughts/suggestions would be highly appreciated.

Thanks.

show what you've already done in your mapping and show you DB schema.

Hello emmanuel,

Thanks for replying. Here is a snippet of my mapping file.

<hibernate-mapping>
<class name="com.islandpacific.hibernate.LineItem"
table="line_item" dynamic-update="true">

<id name="id" type="long" column="id" unsaved-value="0" >
<generator class="vm"/>
</id>

<property name="lineNumber" type="int"
column="line_num" length="3" />

<many-to-one class="com.islandpacific.hibernate.PODetails"
name="poID" column="po_id" />

.................
</class>

So I want to describe that the combination of lineNumber and poID is unique in the table.

There is a slight change in the table now as poID is the primary key of another table po_details. The mapping for that table is as follows ...

<hibernate-mapping>
<class name="com.islandpacific.hibernate.PODetails"
table="po_details" dynamic-update="true">

<id name="orderID" type="int" column="order_id" unsaved-value="0" >
<generator class="vm"/>
</id>

<property name="poNumber" column="po_number"
type="string" length="10" not-null="true" unique="true"/>

.....
</class>

The table for po_details looks like below

PK : order_id
po_number
revision_number
......

The table for line_item looks like below
PK: id
line_num
FK: order_id
class
size
color
.....

Hoping to hear from you...

Thanks.

Is this a bigger problem than it looks like? I thought this must be something primitive. I do not have any hibernate resources with me now and am in the process of getting the books. All I refer to is the Hibernate reference document. I have gone through that a couple of times and still do not see anything other than the composite-element suitable for my needs.

Any suggestions/pointers would be heartily welcomed.

Thanks,

Rave.

There is no good solution I guess :
- check this uniqueness at the Java level in a process layer
- add a unique constraint in you DB

Hi,

I am looking for a similar solution.

Have a table, in which the combination of the foreign key and one column have to be unique.

Is there any Hibernate solution for this?

My workaround now is to change the database schema after hibernate creates the tables.

But I think it's no good solution to change the database schema by hand, because the hibernate mapping files should be the master template for the database.

Any solution in Hibernate mapping files available?

Thanks in advance,

Pieper

Hi,

is there no possibilty to do this in Hibernate mapping file?

Regards,
Pieper