I’ve been doing a lot of work with NHibernate lately, particularly with named queries. It took a while to get it just right, so I figured it would be helpful to others (and to myself in the future) to note some of the gotchas and how-to steps to get it just right.

What is a named query?

An NHibernate named query is essentially a native SQL statement that can be invoked by NHibernate and can return strongly-typed object data. It allows you to leverage native SQL code — parametrized statements or stored procedures — to perform complex data manipulation and retrieval.

In other words, let’s say you’re writing a baseball game, and you have three objects in your domain model: a Player, a Team, and a DrugTestResult model. You write a stored procedure, spSelectPlayersByLastDrugTestDate, which returns all players who haven’t had a drug test since a given date.

Now that you have a domain model and a SQL statement, how do you execute . . .

→ Read More: Executing native SQL using NHibernate named queries