WeblogCategoryAssoc represents association between weblog categories in the weblog category hierarchy. For each category, there will be zero or one parent category association and zero or more grandparent associations.
Creating a new Cat
WeblogManager creates new Cat, not a PO
Cat has a parent Cat or null if parent is null. Parent must be PO.
On save, CatAssoc will be created for Cat.
Saving an existing Cat
If Cat has a new parent Cat, then update all of Cat's CatAssocs
@author David M Johnson
@ejb :bean name="WeblogCategoryAssoc"
@hibernate.class lazy="false" table="weblogcategoryassoc"
@hibernate.cache usage="read-write"