I was in the process of pointing my NHibernate to an Oracle 10g instance using ODP.Net and I received the below error message:
The connection.driver_class must be specified in the NHibernate configuration section.
I had been using a locally installed Microsoft SQL Server database up to that point. It turns out that I needed to add the driver class property to my configuration file.
<property name="connection.driver_class">
NHibernate.Driver.OracleDataClientDriver
</property>
This interesting thing was that I didn’t have the driver class property configured for my Microsoft SQL Server instance. It worked without it. After the fact I did add it.
<property name="connection.driver_class">
NHibernate.Driver.SqlClientDriver
</property>
Perhaps because I had the database on my local machine, the Data Source was enough for NHibernate to make the connection. If you know, leave a comment.