One class map to two existing tables

Question

I have two existing tables, inventoryTbl and supplierTbl
inventoryTbl has following columns:
inventoryIdCol ( Primary Key )
inventoryTypeCol
inventoryAmountCol
supplierIdCol ( Foreign key to supplierTbl )
supplierTbl has following columns:
supplierIdCol ( Primary Key )
supplierNameCol
supplierAddressCol
I have on JDO Class called inventory which want to map to the above
two tables.
it has all these fields:
inventoryId;
inventoryType
inventoryAmount
supplierIdCol
supplierName
supplierAddress
How do I implement it?
Question 1:
Notice Kodo DTD has fk and join extension. Can I use them to implement?
If so, could you give us an example? there is no example in the Kodo
package.
Question 2:
Notice Kodo Developer guide mention the key-column and ref-column.
But by definition, they are only used for Collection/Map field type.
My case is neither of them. they can not be used in my case?
Question 3:
Any other way? Kodo developer guide mention the 'custom-mapping'
extension. How do I use it?
thanks,
John

Answer 1

Answer 1: There are no fk and join extensions. They are used in our
reversemapping process. Kodo 3.0 has more verbose extensions (if
you want to look at that (beta) version's documentation).
Answer 2: You won't need them to map your situation (see later)
Answer 3: I would suggest against this... it is not a trivial task nor
well documented and WILL change with our upcoming 3.0 release (which is
far easier to customize and documentation-wise).
All those things being said, short of trying out Kodo 3.0 which is in
(early) beta form, the easiest way is to map the supplierTbl to its own
class. Note that this class does not have to be exposed at the
application level. For example:
public class Inventory {
private Supplier supplier;
public String getSupplierName () {
return supplier.getSupplierName ();
public void setSupplierName (String name) {
supplier.setSupplierName (name);
One can do more funky stuff using javax.jdo.InstanceCallbacks (jdoPostLoad
() and jdoPreStore ()), however, I find the above strategy to be the
easiest as it doesn't require any JDO dependencies in your application
classes as well as requiring a lower level of undestanding of the
PersistenceCapable lifecycle.
On Thu, 14 Aug 2003 20:19:54 +0000, w wrote:
>
I have two existing tables, inventoryTbl and supplierTbl
inventoryTbl has following columns:
inventoryIdCol ( Primary Key )
inventoryTypeCol
inventoryAmountCol
supplierIdCol ( Foreign key to supplierTbl )
supplierTbl has following columns:
supplierIdCol ( Primary Key )
supplierNameCol
supplierAddressCol
I have on JDO Class called inventory which want to map to the above
two tables.
it has all these fields:
inventoryId;
inventoryType
inventoryAmount
supplierIdCol
supplierName
supplierAddress
How do I implement it?
Question 1:
Notice Kodo DTD has fk and join extension. Can I use them to implement?
If so, could you give us an example? there is no example in the Kodo
package.
Question 2:
Notice Kodo Developer guide mention the key-column and ref-column.
But by definition, they are only used for Collection/Map field type.
My case is neither of them. they can not be used in my case?
Question 3:
Any other way? Kodo developer guide mention the 'custom-mapping'
extension. How do I use it?
thanks,
John--
Steve Kim
[email protected]
SolarMetric Inc.
http://www.solarmetric.com