I believe this is possible with Hibernate. I don't know if it's in NHibernate (yet).

Since I'm using NHibernate to produce my database schema, I'd like it to create all the indexes from just the mapping files as well. One of my tables, for example, will usually be searched by a string column rather than its id (int) column. Can I get NHibernate to create an index on that column? I use unique="true" to create unique constraints with indexes, but how can I get a non-unique index created?

Thanks.

I found my own answer in the Hibernate documentation:

For example, the following property mapping will create an index in the database on that column.