Auditing data with Envers

A common business requirement in application development is auditing changes to stored entities. Which entities were added, modified, or deleted? Who made the change? Which properties were modified?

In this recipe, we'll use NHibernate Envers, which provides exactly that kind of auditing functionality.

Getting ready

Complete the Eg.Core model from Chapter 2, Models and Mappings.

How to do it…

1. Create a new project named Eg.Envers.
2. Copy the Eg.Core model and mappings from Chapter 2, Models and Mappings to this new project.
3. Change the namespace and assembly references in the mappings to Eg.Envers.
4. Install NHibernate Envers using NuGet Package Manager Console, by executing the following command:

   Install-Package NHibernate.Envers
   

5. On the Product class, add the following attributes:

   public class Product : Entity
   {
     public virtual string Name { get; set; }
     public virtual string Description { get; set; }
   
     [Audited]
     public virtual Decimal UnitPrice { get; set; ...