How can one delete NHibernate objects using a criteria?

Question

This must be a simple question. Given a criteria, how one deletes the entities satisfying the criteria?

The rationale:

HQL and NH criteria

Answer 1

You may use the criteria to select the IDs of your elements, join them in a string and use HQL to delete them?

Something like:

public void Delete(ICriteria criteria, string keyName, string tableName)
{
    criteria.setProjection(Projections.Attribute(keyName));
    IList itemIds = criteria.List();

    string collection = string.Join(",", Array.ConvertAll(itemIds, Convert.ToString));

    Session.HQL(string.Format("delete from {0} where {1} in ({2})", tableName, keyName, collection);
}

This code was not tested or compiled (in particular I'm not sure of the HQL section), but I think that you got the idea: we don't fetch the whole objects thanks to the projection, but only the indices.