Concept of API's

[Carty Ellis]

I have a concept question. A piece of software I am part of a development team on is having a slight problem, and I'm looking for some astute direction. The tools in question are Spring and Hibernate. We have an object mapped to a specific version of a database with hibernate. My reasoning is that when I pick up and object from that database, it should be the responsibility of the API to allow me to return that object to a different version of the database (some columns have been added), not the responsibility of the program retrieving and sending the object.

What is the wisdom at the Saloon on this topic?

[Paul Sturrock]

What you are trying to do is possible. Using Hibernate you could happily retrieve an object from one data model version and store it in another, assuming any extra fields added to the table this object is mapped to are nullable, or use a DEFAULT constraint. You couldn't go the other way though, and remove fields from a table.

To do this you will need retrieve the object, switch SessionFactories, open a session and save the object.
[ September 13, 2005: Message edited by: Paul Sturrock ]

[Carty Ellis]

Is it possible to extend the object retrieved from deserialized in order to add a value to a new column if the new column is both "not nullable" and a default constraint is not appropriate? Then to open a new session and put out the object?