Is there any way to set up a hibernate mapping strategy such that i can create an instance of the mapped class, and only set a few parameters, then when I save it to the database, only update those fields that are not null in my mapped class object? I am writing a loosely coupled application which sends objects to the web layer in JSON format, and I don't want some of the more sensitive fields to be exposed to the client, but i need them to be mapped fields on the business logic layer. As it is right now, if I omit these sensitive fields from my JSON objects (essentially DTO's), the values are overwritten with "null" when I write the objects back to the Hibernate session. Any help you could provide would be awesome.

One solution might be to create a second Hibernate object that has the fields needed by your DTO. Your business logic layer could be a sub-class of the the "DTO-Entity" containing the sensitive fields. This way, if the parent class won't muck with the fields from the specialization.

Another feature that maybe useful to you is enabling dynamic-update="true" on the class element of your mapping file. Or, if you using annotations, add the following:


This tells Hibernate to generate a SQL statement for only those values that have changed.

You could also manually generate the HQL that updates the specific properties:

http://www.hibernate.org/hib_docs/v3/re ... tch-direct

Anything else would have to managed by you as only you know what field need to be truly updated.



Ryan-