Getting Started with NHibernate - Part 2

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This post is a continuation of previous post. This post gives a startup using NHibernate framework. In this post we are discussing the Data access components.

In Data Access project, I have created a class CustomerDA for specifying Data Access methods. This class has the following method.

1. GetConfigFilePath – This method is a Private method, used for getting the physical path of nhibernate.config file located in UI Project.
   

   /// <summary>
   /// Geting the nhibernate.config file path
   /// </summary>
   private string GetConfigFilePath
   {
       get
       {
           string path = HttpContext.Current.Request.PhysicalApplicationPath;
           if (!path.EndsWith("\\"))
               path = path + "\\";
   
           path = path + "nhibernate.config";
           return path;
       }
   }

2. Get – Method for getting Customer details for a particular Customer.
   

   /// <summary>
   /// Get the customer details with Customer Id 
   /// </summary>
   /// <param name="customerID"></param>
   /// <returns></returns>
   public Customer Get(string customerID)
   {
       try
       {
           // Create the configuration object
           Configuration cfg = new Configuration();
           cfg.Configure(GetConfigFilePath);
   
           // Create the session
           ISessionFactory sessionFactory = cfg.BuildSessionFactory();
   
           // Open the session
           using (ISession session = sessionFactory.OpenSession())
           {
               // Get Cusomers
               IList<Customer> customers = session.CreateCriteria(typeof(Customer))
                                               .Add(Expression.Eq("CustomerID", customerID))
                                               .List<Customer>();
   
               // Get the first customer (as CustomerID is unique, it will be always one)
               Customer customer = null;
               if ((customers != null) && (customers.Count > 0))
                   customer = customers[0];
   
               return customer;
           }
       }
       catch (Exception ex)
       {
           throw ex;
       }
   }

3. GetAll – Method for getting all the Customer in a list from the database.
   

   /// <summary>
   /// Get all the customer from the database.
   /// </summary>
   /// <param name="sortBy"></param>
   /// <param name="sortType"></param>
   /// <returns></returns>
   public IList<Customer> GetAll(string sortBy, SortType sortType)
   {
       try
       {
           // Create the configuration object
           Configuration cfg = new Configuration();
           cfg.Configure(GetConfigFilePath);
   
           // Create the session
           ISessionFactory sessionFactory = cfg.BuildSessionFactory();
   
           // Open the session
           using (ISession session = sessionFactory.OpenSession())
           {
               // Create Criteria
               ICriteria criteria = session.CreateCriteria(typeof(Customer));
   
               if (sortBy != null) //If sortBy values pass (Pass null if not required)
                   criteria.AddOrder(sortType == SortType.Ascending ? Order.Asc(sortBy) : Order.Desc(sortBy));
   
               // Get Cusomers
               IList<Customer> customers = criteria.List<Customer>();
   
               return customers;
           }
       }
       catch (Exception ex)
       {
           throw ex;
       }
   }

4. Create – Method for creating a Customer
   

   /// <summary>
   /// Create the Customer details
   /// </summary>
   /// <param name="customer"></param>
   public void Create(Customer customer)
   {
       ITransaction transaction = null;
       try
       {
           // Create the configuration object
           Configuration cfg = new Configuration();
           cfg.Configure(GetConfigFilePath);
   
           // Create the session
           ISessionFactory sessionFactory = cfg.BuildSessionFactory();
   
           // Open the session
           ISession session = sessionFactory.OpenSession();
   
           // Begin a new ITransaction
           transaction = session.BeginTransaction();
   
           // Save the given entity.
           session.Save(customer);
           session.Flush();
   
           transaction.Commit();
       }
       catch (Exception ex)
       {
           // Rollback the transaction.
           if (transaction != null)
           {
               transaction.Rollback();
           }
           throw ex;
       }
   }

5. Update – Method for Update an existing Customer.
   

   /// <summary>
   /// Update the Customer details
   /// </summary>
   /// <param name="customer"></param>
   public void Update(Customer customer)
   {
       ITransaction transaction = null;
       try
       {
           // Create the configuration object
           Configuration cfg = new Configuration();
           cfg.Configure(GetConfigFilePath);
   
           // Create the session
           ISessionFactory sessionFactory = cfg.BuildSessionFactory();
   
           // Open the session
           ISession session = sessionFactory.OpenSession();
   
           // Begin a new ITransaction
           transaction = session.BeginTransaction();
   
           // Get existing Cusomer
           Customer existingCustomer = session.Get<Customer>(customer.CustomerID);
           if (existingCustomer == null)
               throw new Exception(string.Format("Can not find the Customer with id: {0}.", customer.CustomerID));
           session.Clear();
           // Save the given entity.
           session.Update(customer);
           session.Flush();
   
           transaction.Commit();
       }
       catch (Exception ex)
       {
           // Rollback the transaction.
           if (transaction != null)
           {
               transaction.Rollback();
           }
           throw ex;
       }
   }

6. Delete – Method for Deleting an Existing Customer. Here I can call this method using Customer Id or Customer object from UI layer.
   

   /// <summary>
   /// Delete the Customer details
   /// </summary>
   /// <param name="customer"></param>
   public void Delete(Customer customer)
   {
       ITransaction transaction = null;
       try
       {
           // Create the configuration object
           Configuration cfg = new Configuration();
           cfg.Configure(GetConfigFilePath);
   
           // Create the session
           ISessionFactory sessionFactory = cfg.BuildSessionFactory();
   
           // Open the session
           ISession session = sessionFactory.OpenSession();
   
           // Begin a new ITransaction
           transaction = session.BeginTransaction();
   
           // Get existing Cusomer
           Customer existingCustomer = session.Get<Customer>(customer.CustomerID);
           if (existingCustomer == null)
               throw new Exception(string.Format("Can not find the Customer with id: {0}.", customer.CustomerID));
   
           // To clean the session, because we just use the 'session.Get' method.
           session.Clear();
   
           // Delete the given entity.
           session.Delete(customer);
           session.Flush();
   
           transaction.Commit();
       }
       catch (Exception ex)
       {
           // Rollback the transaction.
           if (transaction != null)
           {
               transaction.Rollback();
           }
           throw ex;
       }
   }

   /// <summary>
   /// Delete the Custoer Details
   /// </summary>
   /// <param name="customerID"></param>
   public void Delete(string customerID)
   {
       Customer customer = Get(customerID);
       Delete(customer);
   }

I also have an enum which is used in GetAll method for specifying the sorting type.

public enum SortType
{
    Ascending,

    Descending
}

The output of the running sample looks below:

Entry Screen for Customer (using NHibernate framework)

download the working example of the source code in C# here