Yes, I did find a solution. The details:
1) For the data model, I specify a single (auto_increment) field for primary
key and single field for a 'parent' key. Then I create a 'unique index' on the
logical key (e.g., productID) and parentKey. My 'product' table follows:
| create table if not exists store_product (
| productKey integer not null auto_increment,
| parentKey integer,
| productId varchar (40),
| name varchar (80),
| description varchar (255),
| INDEX productKey_indx (productKey),
| INDEX productID_indx (productId),
| INDEX parentKey_indx (parentKey),
| UNIQUE INDEX (parentKey, productId),
| PRIMARY KEY (productKey)
| ) type=InnoDB;
|
All other tables in this hierarchy follow the same pattern.
In the ProductBean, I specify a single field as a primary key:
| /**
| * @ejb.pk-field
| * @ejb.persistence
| * column-name="productKey"
| * @ejb.interface-method
| * @ejb.transaction
| * type="Supports"
| * @jboss.persistence
| * auto-increment="true"
| */
| public abstract java.lang.Integer getProductKey ();
|
| public abstract void setProductKey (java.lang.Integer ProductKey);
|
2) In the ProductBean, I have a finder method defined to find an entry with
the appropriate logical key structure:
| * @ejb.finder
| * signature="ProductLocal findById (java.lang.String iId,
java.lang.Integer pKey)"
| * query="SELECT OBJECT(a) FROM Product AS a WHERE (a.productId = ?1)
AND (a.typeCategory1.typeCatKey = ?2)"
| * view-type="local"
|
3) For the relationship with the parent, I specify a single field key, as
follows:
| /**
| * @ejb.interface-method
| * @ejb.relation
| * name="typeCategory1-products"
| * role-name="product-belongs_to-typeCategory1"
| * cascade-delete="yes"
| *
| * @jboss.relation
| * fk-column="parentKey"
| * related-pk-field="typeCatKey"
| * fk-contraint="true"
| */
| public abstract TypeCategory1Local getTypeCategory1 ();
|
| public abstract void setTypeCategory1 (TypeCategory1Local
typeCategory1);
|
4) in the parent bean (TypeCategory1), I have an 'addChild(ProductValue)'
business method that adds a Product entry. The following code is a summary of
the real code, error checking, etc., removed:
| /**
| * @ejb.interface-method
| * Add a child (product entry).
| */
|
| public Integer addChild (ProductValue child)
| throws FinderException, CreateException, DuplicateException
| {
| Integer objKey = null;
| ProductLocal oLocal;
| ProductLocalHome oHome = ProductUtil.getLocalHome();
| boolean dupfound = true;
| try {
| olocal = oHome.findById(child.getProductId(), getTypeCatKey());
| } catch (ObjectNotFoundException OE) {
| dupFound = false;
| }
| if (! dupFound) {
| oLocal = oHome.create (child);
| getProducts().add (oLocal);
| objKey = oLocal.getProductKey();
| return objKey;
| } else {
| throw new DuplicateException();
| }
| }
|
The rest of the beans in the hierarchy follow this same pattern.
The key to the design here is to separate the logical vs. physical key
structures. I use a single field as physical (and bean) primary key, however,
this pattern allows for any number of fields to be used as a logical key. I
just happen to use a single field in this example. This pattern seems to work
well, but may be a bit slow in adding records....
You can do more tweaking, like adding Value objects for the many side of a
relationship to quickly access children (but be very careful here, you don't
want to read your entire catalog into memory!!), or use the
JBoss.relation-read-ahead xdoclet tag to tell the container to read the entire
child object in one SQL statement, etc.
Hope this helps.
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