I have noticed that when I update a single property of an object and call save, the resulting SQL statement includes all the columns instead of the one that I just touched.

Is this expected or is it something I am doing incorrectly.

Some of the columns in my table are 'text' columns, so the update statement that is generated is huge. Is there some way I can avoid this, and just have Nhibernate update the columns whose respective properties are dirty?

It is expected. If you want to conditionally update certain columns, I recommend putting all the rarely-updated properties in their own class, and mapping that class via a one-to-one association, with cascade="all". If you don't edit the those objects, then isDirty won't notice them and they won't get saved.

You might try to add dynamic-update="true" to You class mappings.

Gert

implement 'finddirty' in an interceptor.. pass it the dirty columns and your good to go. Use in combination with gerts advise