On Jan 22, 2007, at 4:48 AM, Aristedes Maniatis wrote:
On 22/01/2007, at 10:47 PM, Andrus Adamchik (JIRA) wrote:JPA specification supports a notion of "embeddable" class. Embeddable classes can be viewed as multi-column custom types that do not have their own identity and belong to another persistent object. Entities that embed them can override DB column mapping. Currently Cayenne supports single-column custom types via ExtendedType mechanism. We need to expand that to support multi- column Embeddables and mapping via the Modeler.When would you use such a thing? I am trying to think of how this is useful, but perhaps I'm missing the point of the concept. Would this be used to create a type of inheritance between classes, such as company and person having a common billing address class but relating back to completely separate address fields in each of the company and person tables in the db?
The simple case is the Address class that is contained in multiple classes, e.g.
class Employee {
Address homeAddress;
Address workAddress;
...
}
class Business {
Address primaryAddress;
...
}
The EMPLOYEE table contains columns HOME_STREET, HOME_CITY,
HOME_STATE, HOME_ZIP, HOME_COUNTRY, WORK_STREET, WORK_CITY,
WORK_STATE, WORK_ZIP, WORK_COUNTRY. The BUSINESS table contains
columns PRIMARY_STREET, PRIMARY_CITY, PRIMARY_STATE, PRIMARY_ZIP,
PRIMARY_COUNTRY.
There is no separate Address table and no Address instance that exists outside the "owning" Employee or Business instance.
Craig
Also, is it a goal to make 3.0 fully JPA compliant or is that too ambitious in the timeframe (I'm guessing a reasonable target for 3.0 would be some time in 6-9 months).Ari Maniatis --------------------------> ish http://www.ish.com.au Level 1, 30 Wilson Street Newtown 2042 Australia phone +61 2 9550 5001 fax +61 2 9550 4001 GPG fingerprint CBFB 84B4 738D 4E87 5E5C 5EFA EF6A 7D2E 3E49 102A
Craig Russell Architect, Sun Java Enterprise System http://java.sun.com/products/jdo 408 276-5638 mailto:[EMAIL PROTECTED] P.S. A good JDO? O, Gasp!
smime.p7s
Description: S/MIME cryptographic signature
