Hibernate version: 3.1.2

I looked and searched, this might have been asked before ... but I can't find the exact answer:

Is there a way to tell Hibernate NOT to update columns if the entity's properties were not modified ? That is, if only one property out of ten was modified via a setXXX() method, then it should only update that column on the table ?

Reason I ask are:

1) There are some tables that have update triggers on specific columns. The triggers are being needlessly executed despite the old and new values being the same. Some triggers don't even check the old and new values, generating an audit row in another table, even though that column did not change.

2) Some of the tables have lots of columns ( 10 to 20 columns ). Majority of them are real properties ( not a collection / many-to-one or one-to-many mappings ). It would be good to limit the actual updates to those that were only modified.

Thanks,
John

In your class element of your mapping file, add the following attribute:



with this value set, Hibernate generate an update statement for only the changed fields.

Ryan-

Cool. I did not know about that until now. Now why is the default value for this attribute "false", when a default of "true" makes more sense ?

I'm also curious as to why that's not the case. To maintain consistency with older versions of Hibernate that didn't have that feature?

Updating only the changed columns reduces the use of statement caching. If you're always updating the same set of columns then hibernate and the database can cache the update as it's always the same string.

If you only update the changed columns then there is a potential for a different update statement each time so caching is less effective.