We have an application with Oracle backend. The DAO layer is written in C# and uses nHibernet to perform the data operations.To unit test our DAO code, we use SQL Lite which creates the database based on our existing mapping in the project. Some of our nHibernate queries that go to oracle use (+) for outer joins. Now SQL Lite doesn't understand (+). There can be some more syntax from Oracle that SQL Lite doesn't understand. How do we fix problems like these? What are the other database systems that can be used for unit testing the application code. 
Unit test DAO code using SQL Lite when the application database is Oracle
c#;unit testing;nhibernate