I'm trying to simulate 'views' of a single table (row) with several different objects, but am unclear on the possibility and implications of doing so.

Here is an example:



Several things to note are, 1) the common "deviceId" across all three classes, and 2) the visibility of "ipAddress" from both DeviceBase and DeviceInfo.

First, will Hibernate allow me to do this? Next, if so are there implications for cache coherency if updates are performed through these different objects? For example, if I use the DeviceBase object above to update the ipAddress attribute, will queries for a DeviceInfo object with the same deviceId (they are the same row) receive a possibly stale object due to caching? Is caching my only concern?

Inheritance doesn't make sense in this case because they are not separate kinds of objects (i.e. a discriminator would interfere with seeing the same row through different classes). For performance reasons we would like to avoid using separate tables and joins, hence our consideration of this approach.

Any help/insight is appreciated.

Thanks,
Brett

Sounds to me like you should have 1 class: Device with all the fields. Or can some devices have a status but not a vendor and model?

What are you trying to achieve by having separate classes? After you've loaded a device you could narrow the API using interfaces.

It does appear that you _can_do this in hibernate. With the session cache, if you update, say, the ipAddress through DeviceInfo then load a DeviceBase for the same object in the same session then you'll get the old ipAddr in DeviceBase. However, if you flush the changes to DeviceInfo before loading DeviceBase then you'll see the updated ipAddress.